Articles

Plants That Perform In the Hot Summer Sun

We have had some very hot weather here in the Pacific Northwest and in some cases, previous high temperature records have been broken. Not only have we had very hot and sunny days, but there has been no recent rain and the ground is very dry. It is not unusual for us not to have rain in the summer months, but with no rain and high heat, plants can suffer. The diversity of plants always continues to amaze me with some being able to thrive in the hot sun, while others wilt, and the leaves burn.

Most gardeners have their favorite plants for sunny locations and much of the information on these plants is probably trial and error. I have certainly had my share of plants that I thought would perform well in a sunny location, only to find out that I was mistaken and they either died or the leaves became scorched. A helpful hint, that I have mentioned in previous articles, is adding Black Gold® Natural & Organic Just Coir over the soil surface. Coir has high water-holding capacity which is a helpful addition to summer plants growing in containers.

The following is a listing of plants that seem to thrive in the sun and provide summer color with flowers and/or foliage,

Raspberry Ice Bougainvillea

Bougainvillea ‘Raspberry Ice’ is a tender flowering shrub that grows well as a tender perennial or perennial where hardy.

One of my favorites is Bougainvillea ‘Raspberry Ice’. While Bougainvillea is mostly known as a tall and fast-growing vine, ‘Raspberry Ice’ has a low-mounded spreading form which makes it ideal for pots and hanging baskets. With variegated foliage, this plant is attractive even when not in flower with the typical purple flowers, actually bracts. Bougainvillea is a tropical plant and will not survive our winters and I treat it as a summer annual.

Tall Zinnias

What’s not to like about Zinnias (Zinnia elegans hybrids). An old-fashioned flower that continues to be popular in gardens of today. The color range is vast with colors of red, yellow, cream, white, pink, purple, and shades of all of these. The plants have a wide range of height, some are low growing, others tall, and many in-between. They bloom all summer, and the flowers are excellent for cutting.

Tall zinnias are easy to grow and beautiful.

Perennial Coreopsis

There are two new Coreopsis in my garden this year and both have been blooming since I bought them in early June. This easy-to-grow member of the sunflower family has flowers and foliage that are quite diverse. Coreopsis ‘Lightning Bug’ has fern-like foliage and small flowers that cover the plant. Coreopsis ‘SuperStar’ has larger flowers and foliage. With their vibrant flowers, a grouping of either provides a bright spot of color in the garden.

Coreopsis ‘Superstar’ is a favorite of mine. (Image by Mike Darcy)

Cigar Plant

With hundreds of small flowers on a single plant, cigar plant (Cuphea ignea) is known not only for the prolific flowers it provides all summer, but the flowers are also known as a hummingbird magnet. Sometimes call the cigar plant because the flowers are orange-red with a white tip and a dark rink at the end. For a plant that gives continuous color, it’s hard to beat Cuphea!

Cannas

The large bold leaves of a Canna can give a garden a tropical look. With the leaves varying from solid green to different variegations, they can provide color when the plant is not in bloom. Two that I particularly like are ‘Striata’ and ‘Cleopatra’, both of which have outstanding foliage. The impressive Canna ‘Striata’ (syn. ‘Bengal Tiger’) has yellow-striped variegated leaves with a narrow maroon margin and bright orange flowers. ‘Cleopatra’ has leaves that may be partially a dark chocolate color and green or all green or almost all dark chocolate. The flowers are equally variable and can be red, yellow, and often of combination of both colors. It is a very eye-catching plant in the garden.

Canna ‘Striata’ has impressive stripes leaves and colorful flowers.

These are just some sun-loving plants that perform well in Pacific Northwest gardens. All will grow beautifully in garden soil fortified with Black Gold Garden Soil.  The natural and organic amendment adds needed organic matter to enrich soils and encourage strong root growth and plant development.

I find it interesting to try some new plants every year to test their summer sunworthiness. Many of these plants are available at garden centers and can still be planted. The plants will probably be larger than they would have been in the spring and can provide some instant color in the garden. Try one that is new to you!

 

Happy Gardening!

The Best Reblooming Clematis

When visiting older established gardens, if there is a border garden, it will probably contain at least one of these three plants: peony, bearded iris, and clematis. These are often considered old-fashioned plants because they have been regularly planted in gardens for so many years. All three of these plants are generally considered reliable spring bloomers and once blooming. The bloom period can be over several weeks, and there are usually early and late-season varieties, but their flowering time is usually spring and early summer with additional flowers not expected until the next spring. There are, however, exceptions.

Over the past several years, there has been a resurgence of interest to select those that will rebloom. This is especially true with clematis, and with a little effort, a gardener can have plants that will rebloom once and sometimes even twice. I recently discussed reblooming clematis with Linda Beutler, curator of the Rogerson Clematis Collection in Lake Oswego, Oregon, and here are some of her thoughts.

The fully double ‘Duchess of Edinburgh’ can bloom as many as three times in a season. Image from the Friends of Rogerson Clematis Collection archive)

Reblooming Clematis Care

Most clematis grow best in the full to partial sun and like to have their roots shaded and their tops in the sun. After a clematis has flowered, deadhead it, (remove old flowers) and do some light pruning if necessary. Deadheading prevents the plant from setting seed and light pruning removes any dead stems and opens the plant up to more sunlight. Fertilize the plant at this time. Linda said a rose & flower fertilizer is generally good. At the Rogerson Clematis Collection, they use a fertilizer with an NPK, (Nitrogen- Phosphorus-Potassium nutrient numbers on the bag or box) ratio with numbers under 10. Currently, they use a 5-7-2. Often, 30-45 days after fertilization, the plant will re-bloom. For a full list of care tips, visit the Rogerson Clematis Collection page on clematis care (click here).

Five Recommended Reblooming Clematis

‘Blue Ravine’ is a large-flowered rebloomer. (Image from the Friends of Rogerson Clematis Collection archive)

Naturally, some plants will consistently rebloom easier, and for that consistent rebloom the following are five clematis varieties that Linda recommends.

  1. Clematis alpina ‘Pamela Jackman’ (Zones 3-9) flowers first in April and reblooms well, often in late summer. It requires trellising and can also be grown well in a container. With this clematis, you can have April in August.
  2. Clematis ‘Elegant Rhythm’ (Zones 5-9) is a handsome herbaceous perennial clematis named and introduced by Joy Creek Nursery. If you do not allow it to set seed, it will rebloom through late spring and summer, just like annual Scabiosa or perennial Astrantia.
  3. Clematis ‘Duchess of Edinburgh’ (Zones 4-9) is a double that can bloom as many as three times in a long growing season. Deadhead the spent blooms and fertilize with most any fertilizer for roses. The fully-double flowering clematis will often produce flowers that are less doubled when they rebloom.
  4. Clematis ‘Blue Ravine’ (Zones 4-9) is an excellent large-flowered variety and has the added advantage of flowering well—if paler—in partial shade. The photo above was taken in September 2020 and looks as though it were in spring.
  5. Clematis ‘Niobe’ (Zones 4-9) is a deep-red variety (pictured below reblooming in the autumn). Look closely at the image and you can see this clematis is growing through and is supported by another plant. This particular support plant is Osmanthus heterophyllus ‘Goshiki’.
The deepest-red-flowered ‘Niobe’ is growing up an Osmanthus shrub. (Image from the Friends of Rogerson Clematis Collection archive)

Clematis are often grown in this way using another plant for support. Often some of the old garden roses are used because they not only offer a good support system, but the clematis will flower again when the once-blooming roses are finished.

If you are visiting the Pacific Northwest, and have any interest in clematis, be sure to visit the Rogerson Clematis Garden, which is part of the Lake Oswego, Oregon, Parks & Recreation system. With over 900 taxa represented, it is the most comprehensive collection of clematis within a public garden in North America. Admission is free.

The handsome clematis ‘Elegant Rhythm’ has pendulous flowers. (Image from the Friends of Rogerson Clematis Collection archive)

Outstanding Cannas

Every summer I plant my favorite Canna standby, ‘Striata’. It is the perfect floral backdrop for other bright garden flowers. (Image by Jessie Keith)

Cannas are summer-garden workhorses. They grow lushly in the hottest months, only requiring regular water, partial sun, and maybe a hit of slow-release fertilizer at the beginning of the season. Their leaves are bold and lovely, their tropical flowers come in lots of warm pretty colors, and hummingbirds are prized pollinators. The plants also spread and are easily divided and shared. My garden will never be without one.

Canna Origins

Hummingbirds love visiting all canna blooms!

Cannas (Canna hybrids, Zones 8-11) are subtropical to tropical and American. There are 12-21 accepted species, depending on who you reference. These are found in Mexico, Central America, the Caribbean, and tropical South America. The common garden type is Canna × generalis, a hybrid of several species. They were cultivated by native Americans, presumably for both their attractive flowers and fleshy, edible roots. In the late 1900s, cannas were popularized in European and then North American gardens. Since this time, many attractive hybrids have been developed, with new varieties appearing now and then.

Ten Favorite Cannas

Red-flowered cannas, like ‘Kreta’, are sure to attract hummingbirds.

Alaska‘ (3-4 feet): Large cream-colored blooms are the great beauty of this compact canna, and its blue-green foliage is also respectably pretty. It gets all-around rave reviews.

Australia‘(4-5 feet): Large red flowers and big bronzy-purple leaves make this impressive canna a standout. If you are looking to fill a large space with lots of reliable color, this is your canna. It contrasts well with orange- and yellow-flowered plants.

‘Alaska’ is a compact, cream-colored canna.

Cleopatra‘ (4-5 feet): Expect explosive fireworks of color with ‘Cleopatra’. Its impressive green leaves have irregular blocks of dark purple. These are in stark contrast to its flowers, which are half red and half yellow with red spots. Expect it to receive many compliments.

Kreta‘ (3-4 feet): Here is a great canna for nonstop flowers. Its numerous red blooms are prolific and attract lots of hummingbirds and rise above large green leaves.

Musifolia‘ (6-8 feet): This old canna variety is grown for its tall stature and impressive large leaves with hints of red and purple. In the height of summer, it will also offer spikes of small red flowers.

Phasion‘ (syn. ‘Durban’ and ‘Tropicanna’, 3-4 feet): Most regard this as the most electrifying of all cannas. Few garden plants can challenge its impressive tropical palette of colors. Its striped leaves alone are a masterpiece, and its brilliant tangerine-orange flowers add the winning touch.

Striata‘ (syn. ‘Praetoria’, ‘Bengal Tiger’, and ‘Aureostriata’, 5-6 feet): My garden is never without a ‘Striata’ for summer color. Its pale-yellow striped leaves provide a more neutral backdrop for the light orange flowers it produces from midsummer to frost in my area.

Toucan® Coral is a beautiful compact canna from Proven Winners®. (Image thanks to Proven Winners®)

Tenerife‘ (3-4 feet ): Big golden flowers speckled with deep orange-red make this an extra lovely compact canna. Its leaves are medium green.

Wyoming‘ (3-4 feet): I always confuse ‘Wyoming’ and ‘Australia’ because they are comparable in every way except flower color. This one has beautiful orange flowers to offset its purplish-bronze foliage.

Toucan® Series (Scarlet, Yellow, Dark Orange, Coral, 2.5-4 feet): Toucan cannas are big bloomers on short-statured plants. They come highly recommended for containers. Expect them to perform beautifully all summer long.

Canna Care

Canna rhizomes are easy to plant, dig, and divide.

Cannas are lush, tropical to subtropical perennials that grow best in the full to partial sun. They thrive in rich moist to average soils–the addition of organic matter at planting time is recommended. Black Gold Garden Soil is a great choice. Provide a boost of continuous-release fertilizer formulated to encourage good growth and flowering. They originate in warm, humid, rainy areas and appreciate regular water. Many even grow well along pond margins or boggy spots. When conditions are warm, they will flower. If they are not hardy where you live, dig their dense, fleshy rhizomes in the fall and store them in a cool, dark place through winter. Plant them again outdoors when the soil has warmed and frosts are gone.

Canna Yellow Streak Virus

Several viral diseases will put a damper on canna growth and flowering. The two most common are the canna yellow streak virus (CaYSV) and the canna yellow mottle virus (CaYMV). Infected plants show abnormal leaves with browning or yellowing streaks or mottled patterns. If your canna leaves exhibit these, dig and dispose of them immediately. When replacing them, buy only certified virus-free stock (specialty growers are usually the most reliable source). Be sure not to reuse the potting soil, if your diseased plants were in containers.

Favorite Old & New Salvias For Flower Gardens

The red and white ‘Hot Lips’ is heat-tolerant and beautiful.

It would be difficult to come up with a group of plants that can add as much to the garden, in so many ways, as the flowering sages in the genus Salvia. Their colorful, two-lipped blooms are lovely and the many garden representatives have diverse growth habits, flower colors, fragrance (usually in the leaves), as well as being long-blooming and low-maintenance.

In addition to the above-mentioned attributes, salvias are excellent plants for a pollinator garden–attractive to bees, butterflies, and hummingbirds–and most are summer bloomers that love sunny garden spots. In my garden, the flowers are hummingbird magnets. It is delightful watching the territorial antics of these amazing birds.

Of the more than 900 species of these mints (Look for the square stems!) distributed throughout the temperate and tropical zones of the world, only several species are commonly cultivated in the garden. With so many types of salvia across the world, it stands to reason that there is lots of variation among the species and their hardiness. While many are technically perennial and perform exceptionally well in my Pacific Northwest summers, they may not survive a winter. Poor drainage can be a factor for winter survival, so I add additional perlite for increased drainage when planting them. Gran-i-Grit and coarse sand can also improve the drainage of raised gardens to enhance salvia survival.

Great Garden Salvias

‘Amistad’ has glorious purple flowers that hummingbirds love.

For me, salvias were a late addition to the plant palette in my garden, however, once I started growing them, it was as though I could not stop. I re-planted favorites each spring and always add some new varieties that I have not grown before. I discovered they were wonderful container plants, and now we always have salvias in pots on our deck. From my own experience, I have discovered what I would consider outstanding performers. Below is a listing of some of my favorites.

Introduced nearly 20 years ago, Black & Blue sage (Salvia guaranitica ‘Black & Blue’, Zones 7-10) was one of the first ones in my garden. It was recommended by the owner of a local garden center, and this salvia has become such a favorite that I plant it every year. The 4-foot plant has deep blue flowers with black calyces, hence the name ‘Black & Blue’.  Amistad salvia (Salvia guaranitica ‘Amistad’, Zones 7-10) is another good performer with deep purple flowers. It has a more compact growth habit than ‘Black & Blue’ with a final height under 3 feet. Both are excellent hummingbird attractants and will bloom all summer. They are also technically hardy to my area but very sensitive to winter moisture.

Black & Blue sage looks the part with its bicolored flowers.

Proven Winners has recently released a series of salvias in the Rockin series. I have grown several in this series, and they are excellent. My favorite is Rockin® Fuchsia (Zones 9-11) and as the name implies, the flowers are brilliant fuchsia. It is an excellent salvia for a container in a location where bright color is desired. It is also a heavy bloomer and hummingbirds love it. Another in this series that I have grown and liked is Blue Suede Shoes (Zones 9-11), which has light blue flowers with black calyces.

Rockin® Fuchsia is a very heavy summer bloomer.

For fragrance, I have not grown any better than Cleveland sage (Salvia clevelandii, Zones 8-11). This southern California native has the most aromatic leaves of almost any plant that I have grown. It has a mounding growth habit with wrinkly, leather-textured leaves. The flowers are in rounded clusters and may be lavender to purple. Plant this where people can walk by and rub or touch a leaf.

Cleveland sage is a California native with an enticing scent.

Classic garden salvia that has distinct bi-color flowers is Hot Lips littleleaf sage (Salvia microphylla ‘Hot Lips’, Zones 7-10). The flowers are white at the base and bright red on the petals. A grouping of these in bloom makes a very striking summer display that hummingbirds cannot resist.

The flowers of ‘Hot Lips’ appear all summer.

Garden centers are continually increasing their salvia choices for customers. It was not many years ago when the selection was perhaps two to three different kinds, but today that is not the case. If you are new to growing salvias, check with other gardeners to discover what varieties perform best in your particular area. The salvias that I have mentioned are sun-loving, but there are some varieties that require at least partial shade. Others are very reliable hardy perennials.

Try some salvia plants in your garden this season. I think you will become hooked on them just as I am.

Pretty Perennial Ornamental Grasses For Late Summer

Blue fescues are lovely, steely blue grasses that form tidy clumps.

It’s August and here in Indiana we often have days in the 90s.  Many summer perennials, such as daylilies, salvias, and Shasta daisies, are past their prime or have disappeared until next year. Perennial garden grasses, however, are still colorful with their bold plumes and blades. There are many species and varieties available to fit practically any garden.

Perennial grasses range from the diminutive (1-foot or less) to big and bold (6-8 feet or more). Some are dense and colorful while others are airy and textural. Most require full sun, but some will grow well in partial shade. I only grow perennial grasses, so I do not have to fuss with planting new ones every spring. Here are some of my favorites for your consideration.

Sterile Chinese Maiden Grasses

Maiden grasses (Miscanthus sinensis, Zones 5-9) are beautiful, but gardeners need to exercise caution when choosing one. Many of these Asian-native grasses are invasive to North America, so it is best to choose varieties with low or no seed set. One of my favorites Miscanthus is the 6-foot-tall ‘Zebra Grass’, which has an unusual pattern of horizontal-striped bands of yellow across the green blades, but it is not sterile. Thankfully, they have come out with the smaller 3-foot-tall ‘Bandwidth‘, which has all of the good looks while being infertile. In late summer it sends up feathery, golden-brown plumes that produce no fluffy seeds.

Another beautiful, yet invasive, variety is the 6-foot-tall, graceful ‘Morning Light’ with its narrow, green blades with white edges and midveins. The clump reflects light, giving the plant a shiny appearance. The reliably sterile My Fair Maidenis a good replacement. It reaches a whopping 6-8 feet and has very showy plumes that glisten in the sun.

Maiden grasses do best in full sun and need regular water since they don’t like dry soil. Give them plenty of space to grow. These clump-forming grasses widen with age. If you want a tall hedge but don’t want to wait around for slow-growing shrubs or trees, plant maiden grasses instead. They are fast-growing and dense. Wear long-cuffed gardening gloves when you cut the old clumps back to 18 inches in early spring.

Switchgrass

Cheyenne Sky has blades that turn shades of red. (Image thanks to Proven Winners)

A simply gorgeous native switchgrass (Panicum virgatum, Zones 4-9) variety from Proven Winners is Cheyenne Sky. The deer-resistant grass forms a tight, upright clump of blue-green leaves that turn wine-red in early summer and stay that way until frost. It needs full sun and is drought-tolerant once established. At only 3 feet tall, it looks beautiful in large containers as well as in the garden. The clumps spread over time. Leave the dry blades and airy panicles for winter beauty and cut them back in late winter before they begin growing again.

Muhly Grass

Muhly grass has pink plumes that are wonderfully showy.

An unusual and extra-beautiful grass for fall color is the pink muhly grass (Muhlenbergia capillaris, Zones 5-9), or pink hair grass, which is native to barrens and prairies of the eastern United States. In fall, it sends up large, 12-inch, frothy, panicles that look like bright pink clouds. These can last from September to November.  The leaves are very narrow and shiny. Pink hair grass reaches up to 3 feet tall, likes well-drained soil, and is drought tolerant once established. It looks best when planted in groups and grows best in full sun but will tolerate more shade than other grasses. Regal Mist® is an extra showy variety to try.

Blue Fescue

Blue fescue is semi-evergreen, so it continues to look outstanding in winter.

Blue fescue (Fescue glauca, Zones 4-11) is a wonderful compact ornamental grass for the front of the flower garden. It is round clump-forming grass with straight, narrow, blue blades. At only 8-12 inches tall (foliage) it is one of the shortest ornamental grasses.  It is drought tolerant and does well in rock gardens or any other dry-soil area.  Blue fescue sends up its flower heads in late spring–by summer they turn tan. Two excellent varieties are ‘Elijah Blue’ and ‘Boulder Blue’. Old specimens plant sometimes die back in the center. At this time, divide them to rejuvenated clumps, and replant them elsewhere.

Red Hood Sedge

For interest, I decided to add one sedge to the list–sedges being close relatives of grasses. Red hood sedge (Uncinia rubra, Zones 7-10) is a stunning evergreen sedge species from New Zealand that is so tempting to me. The beautiful, cascading, 1-foot mounds have bright, glossy, red blades. Red Hood Sedge will grow in full sun or full shade, so you can tuck them in among your hostas. It grows well but does not require, very wet soil, so it can be planted where other grasses would probably not make it. Choose a spot or pot with moist, rich soil, and do not let it get too dry.  An excellent variety is ‘Everflame’, which has undulating red blades.

Why Are My Tomato Leaves Curling?

Upward curling tomato leave indicates stress more often than disease.

“Lots of my tomato plants have curling upward leaves, and in most cases only edge damage. Why?” Questions from James of Greenville, South Carolina

Answer: There is a Tomato Yellow Leaf Curl Virus, but your plant lacks several of the symptoms, including stunting, yellowing, and eventual leaf browning. Tomato plants more commonly experience physiological leaf curl when subjected to various environmental stresses. In this case, I believe yours is caused by environmental stress.  Here are four possible sources of stress.

Environmental Tomato Leaf Curl Causes

  1. Too little or too much water — Vines fail to grow as well when water is lacking, and they develop root rot when there is too much water. Either can cause leaf curl. Regular, even watering will yield the best results.
  2. High heat — Temperatures over 85 degrees F will cause most tomato plants stress and sometimes leaf curl. Some tomatoes are more heat-tolerant. Two of the best heat-tolerant varieties include the large, red-fruited ‘Heatmaster‘, which can take the high heat of the South, and disease and heat-resistant ‘Heatwave II‘, which bears deep red tomatoes with good flavor.
  3. Wind stress — High winds cause rapid water loss from the leaves and stresses vines. Leaf curl can result.
  4. Herbicide damage – Glyphosate herbicide damage is most common. It can cause this type of leaf appearance if a small amount reached your tomatoes from a downwind application.

Could any possibilities be the cause? Please let me know. In the interim, click here to read more about leaf curl, and watch the video below about growing tomatoes to perfection!

Happy gardening!

Jessie Keith

Black Gold Horticulturist

Why Are My Cucumbers Bitter?

“I am growing the same cucumbers this year as last year.  Every cucumber this year looks beautiful but tastes very bitter and is inedible.  I believe I am providing adequate water, though due to the heat the plants still wilt during the day. What can I do to improve the flavor? ” Lisa of Marietta, Pennsylvania

Answer: There are two things that can cause cucumbers to become bitter – the cultivated variety and environmental stress (heat stress, water stress, or disease). A great Oregon State University (OSU) article on the subject quotes the vegetable breeder, Jim Myers of OSU. He explains that the source of cucumber bitterness is caused by the natural plant chemical, cucurbitacin. It exists in high quantities in the leaves and stems of cultivated cucumbers. During stressful summers, concentrations can build up at different levels in the cucumber fruits as well; often at the blossom end. What’s odd is that sometimes a single plant may have some bitter fruits and some nice-tasting cucumbers, so taste each one to double-check before composting. The same plant may also produce sweeter fruits as growing conditions become better.

Non-Bitter Cucumber Varieties

Some varieties tend to reliably produce sweet cucumbers, even under stress. Here are five excellent cucumbers that resist bitterness.

  1. Katrina‘- The crisp, seedless, Beit-Alpha-type cucumber is also very disease-resistant and stays sweet.
  2. ‘Jibai Shimoshirazu’ – This heat-tolerant, Japanese snacking cucumber never gets bitter!
  3. ‘Green Light‘ – There is a reason that this cucumber was a 2020 All-America Selections winner. Its fruits are crisp, sweet, prolific, and resist bitterness.
  4. Marketmore 97– This classic, disease-resistant cucumber is known for its ability to stay sweet, even when stressed.
  5. ‘Unagi’ – After reading about this one, I plan to grow it next year. Its hybrid cucumbers are crisp, sweet, and very prolific.

I also recommend that you watch the video below to learn how to grow cucumbers to perfection. I know that it can be difficult in years where high heat, drought, and even excess rain are problems, but the video contains some good growing tips.

Happy gardening,

Jessie Keith

Black Gold Horticulturist

Growing Gorgeous Gladiolus

There is nothing more beautiful in the summer than sword lilies (Gladiolus hybrid) in a vase or the garden. Their stately stalks of glowing, fragrant flowers come in an array of colors that just can’t be beat! Most gardeners grow them for cut flowers, but glads can also be carefully worked into summer flower borders for floral impact. There are also compact types suitable for border edges and even containers!

A Short History of Garden Gladiolus

Gladioli have bulbous root structures called corms that can easily be dug in fall for winter storage where they are not hardy.

Though Gladiolus species exist across much of the Old World, most garden gladioli originate from complex hybrids of numerous South African species–South Africa being the world center of Gladiolus diversity. World travelers and collectors brought the first South African specimens to Europe in the mid-1700s, and the earliest hybrids appeared by the early- to mid-1800s. Commercial nurseries continued developing their own hybrids (and do to this day), and the flower took off in popularity. By Victorian times, when meanings were attached to every flower, red gladiolus flowers signified love and passion, while pink ones meant femininity and motherly love.

Planting and Caring for Gladiolus

Byzantine sword lily is a beautiful species that is quite hardy.

Start planting gladioli a week after one’s last frost date (click here to determine your last frost date). Choose a sunny spot with fertile, well-drained soil that’s high in organic matter. To keep waves of these short-season flowers blooming from early summer on, plant more corms in two-week intervals until late June. Gladiolus have bulbous root structures called corms that need to be planted in 5- to 6-inch holes.  I always put some fertile, OMRI Listed Black Gold Natural & Organic Garden Soil and bulb fertilizer in the bottom of the hole to ensure good growth. Plant corms in rows 6 to 8 inches apart in a cutting garden or more closely in small groups of 5 to 9 corms mixed in with tall, bushy perennials to provide upright patches of bright color. Water evenly. Gladiolus do not like wet feet or parched soil conditions.

Glads are one of the most long-lasting cut flowers for bouquets, which is why commercial florists love them. They can last for a week or two in a vase. Pick them when the stems just start blooming and remove the lower leaves. Cut the stems diagonally with sharp shears, and put them in water fortified with cut-flower food. A tablespoon of fully sugared lemon-lime soda to a quart of water also works.

Some gladiolus are hardy but most are tender. Gently dig the corms of tender types up in fall when their leaves turn yellow.  You will find new, small cormlets attached to the main corm. Keep them all to grow new plants, though the cormlets will take a full second season to reach flowering size. Put the corms in a warm, dry place for 2 weeks until they are dry. For storage, hang them in mesh bags in a cool, dry place through winter.

Gladiolus to Grow in Gardens

Unsupported tall glads tend to fall over, which is why caging or staking is recommended.

There are several types of gladiolus for gardeners to grow.

Standard sword lily (Gladiolus hybrids, Zones 8-10) range in height from 3 to 6 feet tall and may have up to thirty 5- to 6-inch flowers on each stem. There are hundreds of exciting varieties. A festive choice is ‘Frizzled Coral Lace‘ with lacy coral-pink flowers that fit the name. The rose and peach ‘Guinea‘ is a very pretty extra tall one, and the breathtaking ‘Zizanie’ has large blooms in broken shards of red and white. When planting taller glads like these, choose a location with low wind and surround the plants with perennial or tomato cages to keep them upright. Staking also helps. Planting corms an inch deeper may also assist with stabilizing the plants.

Hooded sword lily (Gladiolus primulinus hybrids (syn. G. dalenii), Zones 8-10) are shorter (2-4 feet) and have an unusual floral shape, with the top petal of the flower hanging over the rest.  They have large blooms, often with ruffled edges, that come in lots of color variations. An extra pretty one is ‘Las Vegas‘ with its primrose-yellow flowers edged in scarlet. The bright red ‘Mirella‘ is another choice selection.

Dwarf sword lily (Gladiolus nanus hybrids, Zones 7-10) reach only 1.5 feet tall. They have large flowers in many colors, including lots of bicolors.  Some of the blooms are white with a rose teardrop on every petal.  Dwarf glads are hardier, so more gardeners can grow them as perennials. Try the super-compact varieties in the Glamini® Series. They are less hardy (Zones 8-10) but perfect for containers or summer borders.

Exceptional Gladiolus species are offered by some bulb companies. One of the best is the hardy Byzantine sword lily (Gladiolus communis subsp. byzantinus, Zones 6-10) with its upright swords of smaller, pink flowers. It is an heirloom that makes a fine addition to old-fashioned perennial gardens. Another to try is the large-flowered branched sword lily (Gladiolus ramosus, Zones 8-10). The brilliant pink, purple, and red ‘Vulcano‘ is spectacular! The hardiest of them all is the butterfly sword lily (Gladiolus papilio, Zones 3-6). Try the bold, deepest-red ‘Ruby‘ with its striking, butterfly-like blooms on 30-inch stems.

More Gladiolus Notes

Hooded gladioli have top petals that create a hood over the bloom.

About leaving corms in the ground, I have some standard red hybrid sword lilies that I did not get around to digging up last fall in my USDA Hardiness Zone 6 garden.  Imagine my surprise when they came up hale and hearty this spring.  I was really surprised! I have read that planting them in 7- to 8-inch holes will increase the chance of them coming back ni northern gardens. Some mulch over the top also helps.

Two excellent companies I recommend for buying glads are Brent and Becky’s Bulbs, and K. van Bourgondien. Glads are blooming bountifully now, but their corms are only sold in the spring, so look for them in March to have the pick of the best varieties. Gladiolus are some of the most gorgeous flowers in the summer garden, so plan to plant some in yours.

How to Prune Spring-Flowering Shrubs

Unless you are removing dead or dying stems, it is best to prune spring-flowering shrubs just after they bloom.

When we think of pruning shrubs, we probably think of late fall and early winter as the ideal time, but this is not always the case. For many spring-flowering shrubs, late spring is the best time to prune because pruning must happen shortly after flowering. Prune off-season, in fall or spring, and you will remove the following year’s flower show! In my own garden, I have many spring-flowering shrubs that need late spring or early summer pruning, so I have learned to time my pruning carefully.

As a rule, most spring-flowering shrubs must be pruned just after or shortly after flowering because this is the time when they set new buds for next spring’s show. Prune them later in summer, and you will end up trimming off next year’s flower buds. For this reason, I have highlighted just a few spring-flowering shrubs and tips for pruning them.

My favorite pruning tools are simple. For large stems, I use a sharp pruning saw or heavy-duty loppers. Bypass pruners (secateurs) are used to manage smaller branches or for deadheading.

Pruning English or Cherry Laurel

The spring flowers of evergreen cherry laurel shrubs are very showy and fragrant, which is why it is important to prune them at the right time.

The plant that immediately comes to my mind that requires at least two prunings a year is the English Laurel, (Prunus laurocerasus, USDA Hardiness Zones 6-8, 10-18 feet), a hedge that my neighbors have. It is an evergreen and fast-growing shrub with dark glossy green leaves and has spikes of creamy white fragrant flowers in late spring. The scent is sweet and powerful, and the shrubs look very attractive in bloom.

My neighbors always give it a heavy pruning after it blooms and then another pruning later in the summer. They also selectively prune to keep the favorite hedge shrubs open and airy, which helps prevent disease problems. Theirs is certainly a taller variety that would take over the house without being pruned twice yearly.

Pruning Azaleas and Rhododendrons

Most often gardeners prune off old azalea and rhododendron blooms after they flower in addition to removing the occasional errant branch.

Rhododendrons and azaleas (Rhododendron species and hybrids, variable hardiness and sizes) will both bloom on second-year wood, so they benefit from spring pruning just after they have flowered. Any later and you risk accidentally removing next year’s blooms. Often the process for both is referred to as ‘deadheading’ because the old flower is removed.  Once the flower has faded, it can be removed. Not only does this look nicer, but it allows the plant can expend energy for new growth instead of seed production.

Deadheading a large rhododendron plant can be quite time-consuming, but it is well worth the time. The plant will physically look better without faded flowers and it saves the plant energy. Some care is required when removing the old blooms. If you look carefully, each has a tender stem that can be snapped off just below the bloom. This is where care is required because it is important to just remove everything above the stem–nothing below because all of the new growth will emerge below the stem.

Generally, rhododendrons and azaleas do not require more intensive pruning unless it is needed for space considerations or plant shaping. If pruning is required, do it immediately after flowering so the plant has adequate time to produce new growth for next year’s flowers.

Pruning Lilacs

The common lilac (Syringa vulgaris, Zones 3-8, 8-20 feet) is another plant that usually requires spring pruning. Once the plant has bloomed, cut off the spent blossoms. To do this, make the cuts back to the first or second pair of leaves on the stem.

If the shrub needs some major pruning, do it immediately after flowering because these lilacs bloom on wood from the previous year. On established plants, cut out a few of the oldest stems yearly and this will encourage new growth. It is also important to remove dead or dying stems, as needed, to keep the shrubs looking their best.

Pruning Tree Peonies

Tree peonies rarely need extensive pruning, but a little yearly deadheading and shaping will keep them performing their best.

The tree peonies (Paeonia suffruticosa, Zones 4-8, 3-5 feet) in my garden have finished their flowering season, so it is time to cut off the old flowers to keep the plant from producing seed. I do this with hesitation because the brown, starry seedpods open to show bright red or black seeds, which can be quite attractive. But, the seeds also take needed energy away from the plant. To have the best of both worlds, I sometimes leave some pods on to look nice. In general, shrubby tree peonies do not need to be pruned extensively, unless it is to remove a stray or dead branch. These architectural slow growers are usually happy just remaining as they are.

Pruning Camellias

My Japanese camellias (Camellia japonica, Zones 7-9, 7-12 feet) put on their greatest show in late winter or spring, but they will also bloom intermittently. Generally do not need pruning except to improve the appearance of the plant or for space considerations. I also remove the old flowers after they are spent to keep the shrubs looking nice and clean. When I do decide to prune, I do it immediately after flowering.

I have found that most spring-flowering shrubs are fairly forgiving with regard to pruning if you are sure to prune them after they flower and no later. If mistakes are made, the plant will survive. Severe pruning may eliminate, or decrease flowering for the next year, but the plant will carry on. Remember that gardening should be enjoyable, so don’t stress too much about potential pruning mistakes. Common sense is a good trait!

How to Weed Gardens: Tips, Tools, and Timing

Weed competition drags gardens down in every way. Ignore your garden for just a couple of weeks, and weeds can take over in a flash–turning once tidy, pretty beds into a tangled mess of green interlopers with no room to spare. If you use the right tools, techniques, and timing necessary to stop a weed takeover, it will save you trouble and reward you with bountiful flowers, vegetables, and fruits.

Common, aggressive garden weeds spread by many means. If allowed to set seed, they will pepper the garden ground with loads of obnoxious seedlings crying to be hoed away. Some have the deepest, most far-spreading root systems that will get away from a gardener in no time if allowed to take hold. Different weeds appear at different times of the season. The most unexpected are prolific winter weeds that will happily fill your beds in late winter and set seed by late spring. Summer weeds require heat to germinate, so you can expect them to start popping up as soon as the weather becomes truly beautiful.

Knowledge is power when it comes to weeds. Here are the essentials necessary to keep your beds happy and weed-free throughout the year.

Know Your Weeds and Their Spreading Power

Don’t pull a perennial weed unless you know that you can get the whole root. Leave one little piece, and it will return!

Your worst weed enemies are perennial weeds that are deep-rooted, fast-spreading, and produce generous amounts of seeds that spread and sprout quickly. Annual weeds are also pesky, but they are generally more shallow-rooted and easier to kill by quick digging and hoeing before they set seed. Here are five of the worst perennial weeds that you may face. From there, I recommend relying on the helpful, Farmer’s Almanac Common Weed List, as well as the excellent UC Davis IPM Guide for common weeds.

Worst Perennial Weeds

Field Bindweed (Convolvulus arvensis): Here is a real monster of a spreader that’s hard to remove. The hardy perennial sets fleshy rhizomatous roots that can extend deep into the ground and many feet from the parent plant. The vine twines and strangles garden plants and then becomes covered with little, white, morning-glory-like flowers that set hundreds if not thousands of seeds. Scrape and dig the seedlings on-site and try to dig the root systems as soon as possible. Smothering and covering infested areas is also a good method, but it takes time. (Click here to learn more about bindweed removal.)

Canada Thistle (Cirsium arvense): Canada thistle (Cirsium arvense) is notoriously difficult to remove and is also a notorious spreader. Its leaves and stems are painfully prickly, and pollinated summer flowers produce loads of puffy seeds that get caught in the wind and spread everywhere. (Don’t let this go to seed anywhere near your yard or garden!) When they sprout, a single plant can become a dense colony connected by deep, rooting rhizomes that are impossible to dig out. Leave just one piece, and it will return. It is also resistant to all but the strongest herbicides.

Aside from using commercial-grade herbicides, the second-best method is to smother plants with weed cloth and mulch until they are gone. Watch out for plants that creep into the grass, once they do, a good broadleaf herbicide is your only option, unless you want to kill everything and start over.

Dandelion (Taraxicum tomentosum): Dandelions spread by seed but can be tamed, so I don’t mind them growing in the lawn. Bees and other early pollinators rely on their golden flowers for pollen and nectar, so they do some good, but they have no place in my garden where they compete with other garden flowers. The deep-rooted perennials are easy to grub out with a garden knife, as long as you remove the whole root and leave no pieces behind. The key is keeping them from setting seed. This is the source of dandelions in the garden. In the spring months, I try to mow low and often to chop off the seed heads before they release their seeds.

Ground ivy (Glechoma hederacea): The aggressive member of the mint family is a ground-covering weed with creeping stems that root and spread fast. Its spring flowers set lots of seeds, which sprout quickly. It also thrives in lawns, so you will need to rely on a broadleaf herbicide for the lawn if you want to truly get rid of it.

Thankfully, this weed is relatively easy to pull, but if you leave even the tiniest piece in the ground it will root and regrow. T manage it well, remove it from garden beds first thing every spring, and then apply a 3-inch layer of mulch, being sure to leave the crowns of garden perennials uncovered. If stray pieces emerge from the mulch, pull them on site.

Nutsedge (Cyperus esculentus): Unless you live in the desert, your garden has likely experienced nutsedge. The aggressive, moisture-loving sedge produces copious seeds in summer that sprout everywhere. Even worst, the plants have fine, spreading roots that develop small, brown nutlet tubers. Leave one tuber in the ground, and it will sprout into a whole new plant. (Quirky fact: The tasty nutlets can be harvested and eaten.)

Nutsedge is not herbicide-resistant, but its tubers are resistant. For this reason, dig out the plants rather than just pulling or spraying them and get all of the tubers. Finally, cover with a 3-inch layer of mulch, and diligently pull any small sedge sprouts as you see them. (Click here to learn everything that you need to know about removing nutsedge.)

Annual weeds, like this summer purslane and pigweed, are easy to pull but prolific self-sowers that sprout in the open soil each year. A good, stout hoe will make quick work of weeds like this.

All of these weeds require good tools for thorough removal, followed up by mulch, and often herbicides or other harsher measures. Once again, annual weeds, like winter chickweed, summer purslane, pigweed, or spotted sandmat euphorbia, are very easy to dig and pull. The key is removing them before they can set seed and germinate or add to your garden’s soil weed seed bank.

Know Your Weeding Tools

Over the years I have used a number of different weeding tools. A few have stood out and become fast favorites. The three key characteristics I look for in a good gardening hand tool are 1. ease of use, 2. working power, and 3. durability. These criteria are met by the following tools:

Long-Handled Tools

Prohoe Rogue Do It All Tool and 7-inch Hoe: The hoes made by this company are wonderfully sturdy and well-made, razor-sharp, and long-handled for those of us that do not like to bend. The Do It All Tool is triangular on one side and has a raking tool on the other. It is perfect for rogueing our deep-rooted weeds. The thin, 7-inch Pro Hoe is ideal for scratching up mats of shallow weed seedlings. These hoes are so strong and sharp, the job will get done in an instant.

Pullerbear Uprooter: For big “weeds” choose a Pullerbear uprooter. In a matter of minutes, an area riddled with small weed trees can be cleaned beautifully roots and all. It works like no other tool I’ve tried. Just clench the base of the sapling or small tree and pull. Ignore the fact that it’s a bit pricey. It will pay for itself quickly in time and effort saved wrangling with hard-to-pull woody weeds.

Short-Handled Tools

Sharp cutting and sawing edges make gardening knives one of the best all-around gardening tools. (image care of the Gardeners Supply Company)
Sharp cutting and sawing edges make gardening knives one of the best all-around gardening tools. (image care of the Gardeners Supply Company)

My trust garden knife (also called a soil knife or Japanese hori-hori) goes with me everywhere. It can cut into the soil to deep roots below and saw through the roots or bases of tough plants. I even use it for harvesting greens and cole crops. One side of the knife is sharp for slicing, and the other is serrated for sawing. They can easily break through the skin, so I use mine while wearing garden gloves and I store it in a leather belt sheath.

Fine-bladed hand trowels are excellent all-purpose tools for weeding and planting. They quickly cut at deep or shallow roots in no time and withstand lots of wear and tear if made well. The “rockery hand trowel” at Clarington Forge is just such a fine-bladed tool, and it’s beautifully crafted for the long haul. Its fine blade makes for easy weeding and planting–especially in heavier or pebbly soils. The narrow rockery hand trowel from Clarington Forge easily expels weeds and gets into small spaces. (image care of Clarington Forge)

The sharp ho-mi will chop deeply into the soil quickly. (image care of Lee Valley)
Sharp ho-mi tools will chop deeply into the soil quickly. (Image care of Lee Valley)

For super fast hand weeding nothing beats the classic ho-mi (hoe-mee), also called the Korean hand plow or cultivator. This sharp, downward-facing tool can get to the base of a dandelion root in seconds with a quick chop, chop, chop. Nothing is more effective. For smaller weeds, I use the side of the ho-mi to scratch and smooth the soil. It’s an excellent tool for lightly aerating the base of a plant or getting to the root of a tough herbaceous weed as well as planting new plugs. If well cared for, a ho-mi will last forever (if cleaned after use and oiled to prevent rust). It’s relatively cheap, too. Long-handled versions are also very useful. Just be careful when chopping away with this sharp tool. Its tip can be nasty.

Practice Timely Weeding

I weed two ways be either casually weeding as I water, harvest, and enjoy my garden, or intensively bed by bed. I do casual weeding almost daily. More intensive weeding is something I do three times a month in summer. I also try to catch weeds at various times in their life cycles.

  1. Catching weeds before they flower and set seed is timely weeding. I write this article as the winter weeds in my vegetable garden have begun to set seed. A busy spring pushed back my weeding schedule, and I am paying for it. Had I removed these weeds just two weeks earlier, before they had begun to release seeds,
  2. Catching weed seedlings before they become large is timely weeding. Digging or hoeing up weed seedlings before they become large and take hold will make your garden life so much easier.
  3. Smothering beds before seeds sprout is timely weeding. Adding mulch in late winter or spring, before weed seeds really sprout is very important to keeping weeds down. Miss just one year, and you will pay for it.

Mulch Properly

 

Natural mulches of all types, like these hemlock needles, make weed covers.

A 2-3-inch layer of mulch, straw, leaf-mulch or compost keeps seedlings from germinating and stops weeds from taking over. It is best to apply mulch in spring after properly weeding your beds and again in fall to ward off winter weeds. (Click here to learn more about the many wonderful mulch options.)

Edge Your Beds

Lots of lawn grasses and weeds like to creep into garden beds. Once in your garden, they become weeds. To stop this, it helps to edge your gardens, especially at the start of the gardening season. Edged beds also look tidier and nicer. Mowing your lawn regularly to stop weeds from flowering and setting seeds is also advisable. (Click here for a tutorial about how to edge beds.)

Consider Solarization

Soil polarization is a method of weed removal that relies on the heat of the sun to kill weeds en masse. Methods vary, but in general, it involves covering a bed area with tacked-down sheets of clear or black plastic for several weeks during the summer. When it works, the heat generated heat cooks everything below–plants, seeds, and all. Keep in mind, the method is used to revive whole beds and remove all weeds, so no desirable plants can be present. It is also less effective further north where summer temperatures rarely exceed 90 degrees F.

Use Herbicides as a Last Resort

Herbicides that really work are generally toxic and best applied by garden professionals. If you have a severe problem with one of the worst perennial weeds mentioned, like Canada thistle or field bindweed, then you may consider resorting to a professional-grade herbicide very selectively applied by a trained horticulturist. Otherwise, they are not needed. More natural means of weed removal are safer and better.

Stay on top of your weeds, and your gardens will prosper. Put aside just a little time each week and it will be a small burden to bear.