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How to Grow Summer Squash and Zucchini

The Middle Eastern ‘Clarimore’ (40 days to harvest) has flavorful, pale green fruits.

The squashes of summer are versatile in summer cooking and some of the easiest vegetables you can grow as long as you have a patch of good, sunny garden ground and a water source. Both summer squashes and zucchini are available in different sizes–bush, short-vine, and long-vine– and only a few pests and diseases cause them grief. Thankfully, rugged, resistant varieties, of the heirloom or hybrid sort, are available to make summer vegetable gardening less problematic.

Five Summer Squash Garden Needs

Good garden soil will yield the best harvests.

Before planting summer squash in a prepared garden bed, raised bed, or large container, be sure you have the following garden and environmental accommodations.

  1. Sun-Full sun (6 hours or more) is required. The more sunshine, the better.
  2. Soil– Average to fertile soil with good drainage and porosity will encourage the best root growth and production. Garden ground amended with Black Gold® Natural & Organic Garden Compost Blend and/or Black Gold® Natural & Organic Garden Soil is recommended. Squash grow best in soil with a pH range of 6.0 to 6.8. If your soil is too alkaline, amend with organic-rich, acidifying Black Gold® Natural & Organic Canadian Sphagnum Peat Moss.
  3. Water– A good water source is needed because fruiting vines require regular water in the heat of summer. Water plant substantially after several days without rain. Even moisture is optimal.
  4. Food– Fertilize as directed with a plant food formulated for vegetables.
  5. Mulch vining summer squash with seed-free straw or hay. The fruits are better protected from pests and fungal diseases on a clean bed of straw. The mulching layer keeps weeds down to boot.

Favorite Summer Squash and Zucchini Varieties

Both summer squash and zucchini originate from . Summer squash can be curved (crookneck), strait, or in patty pan form, and the color ranges from golden to pale green. Zucchini is often strait or bulbous at the end and may be dark green or striped with dark green. The fruits are best harvested when they have reached their projected size and the skin is still soft. The flowers are also edible and often stuffed and fried in Italian cuisine.

Summer Squash

‘Sunburst’ pattypan squashes grow on space-saving bushy plants and can be harvested at all stages when the skin is still soft.

The Middle Eastern ‘Clarimore‘ (40 days to harvest) has pale green fruits that taste nutty and flavorful. The short-vine plants are heat tolerant and productive.

The 5-foot vines of ‘Fort Knox‘ (50 days to harvest) produce straight, golden squash with mild, smooth flesh. The hybrid vines are extra productive.

‘Summer Gold’ (48 days to harvest) is a productive, vining American heirloom plant with gold, strait-neck fruits.

The heirloom pattypan ‘Sunburst‘ (55 days to harvest) is a classic bush-forming variety with gold squashes. Harvest them small for sauteeing and stir-frying.

Zucchini

The vining squash ‘Black Beauty’ is an American heirloom with big harvests.

Black Beauty‘ (50 days to harvest) is a vining American zucchini with smooth, dark green skin.

The pleasantly round ‘Ronde de Nice’ is a European heirloom zucchini prized for stuffing. The bush plants reach only 3-4 feet across.

Romanesco‘ is a vining Italian heirloom with flavorful, ridged squash of pale green striped with medium green. The prolific vines will produce zucchini all season long, so plan to share some with friends and neighbors.

The non-stop producer ‘Zucchino Rampicante‘ can be harvested as a pale green, curved zucchini-like squash or allowed to age as a mild, flavorful winter squash. The Italian heirloom is a family favorite.

Planting Summer Squash and Zucchini

 

Adding a mulch layer of straw will keep weeds down and protects quashes.

Summer squashes are warm-season crops that require summer heat to produce, so the best time to plant them is in late spring after the threat of frost has passed. They grow best in average to fertile soil with good drainage. We recommend you feed your garden soil yearly with rich organic matter and fertilizers formulated for vegetables. Once again, two recommended Black Gold products for added fertility are Black Gold® Natural & Organic Garden Soil, which provides nutrition and needed organic matter, and our fertile Black Gold® Natural & Organic Garden Compost Blend. developing squash.

Squash are fast-growing vegetables and heavy feeders and drinkers, so keep them adequately fed and watered. Any quality fertilizer formulated for vegetables will work. Water after several rainless days to ensure soil moisture is adequate. The ground can be allowed to dry for several days between watering, but don’t let the soil become truly dry.

Summer Squash Problems

Pests, diseases, and poor fruit set are occasional problems with summer squash and zucchini.

Poor fruit set may be caused by a lack of pollinators. Squash plants have two flower types, male and female, and these are strictly bee-pollinated. Vines often produce male flowers first, followed by female blooms (they always have small fruits at the base of the flowers). Without pollination, the developing fruits of female flowers will shrivel. If your area lacks bees, then move the pollen on your own. Simply use a small brush to move pollen from a newly opened male flower to a newly opened female flower. It’s fast, easy, and will yield squash!

Squash vine borers are the biggest threat to these plants. For a detailed description of the pest, read our Ask a Garden Expert answer about how to beat squash vine borers.

Powdery mildew is a common squash leaf disease of late summer.

In hot summer weather, powdery mildew can infect squash leaves. Downy mildew can cause fruit rot in moist weather, especially if days and nights become cool. Downy mildew can appear when weather conditions are cool and moist and will cause fruit to rot and shrivel up early in development.

Future watching and reading:

 

Top 10 Best Tasting Winter Squash

The Best Reblooming Clematis

Clematis alpina ‘Pamela Jackman’ first blooms in April and again later in the season.

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’ blooms 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)

Small-Space Summer Vegetable Gardening

Even one small raised bed can provide summer food and enjoyment for your family.

You want a vegetable garden, but you’re stuck with a postage stamp-sized plot of grass and/or a teeny tiny deck/patio of approximately the same area. What are your options? How about a small raised bed or a few nifty container gardens for some of your favorite veggies?

The key to small-space gardening is starting with a good garden base and planting the right cultivars. Small raised beds will be most productive if they are filled with good-quality soil and situated in the sun. Add a few large, 5-gallon plastic pots to your new vegetable garden venture, rotate your vegetables accordingly, and you will be set.

Small-Space Garden Ground Rules

Small raised beds can be substantial enough to support quite a few vegetables.
  1. Grow compact vegetables because container- and small-raised-bed gardens impose limitations on plant size! Avoid large crops such as corn, melons, pole beans, and vining pumpkins. (Plant lists are below.)
  2. Choose a good location for your garden. Ideally, the spot will have full sunlight (8-10 hours), protection from wind, and quality soil in a bed or pot with good drainage.
  3. Choose the right-sized beds and containers. They should be large and deep enough to support crops. A soil depth of 12″-18″ in raised beds is recommended for deep root growth and productivity. 5-gallon pots are a good size for most potted vegetables. Some gardeners even rely on inexpensive 5-gallon hardware-store buckets with holes poked into the base, especially for pot-grown tomatoes. Ultimately, choosing large containers saves time because they need less water and encourage more growth and productivity.
  4. Choose the right pot. Most gardeners prefer light-colored plastic pots with good drainage for vegetables because they stay cool and plastic retains water better than most pottery. Drain holes are mandatory and maintaining deep saucers at the bottom for water collection helps reduce the need to water as often.
  5. Use quality potting soil and vegetable fertilizer. Do not rely on in-ground garden soil as a planting medium (really!). More organic matter is needed, especially in containers. We recommend raised bed soil amended with Black Gold Natural & Organic Raised Bed Mix and pots filled with Black Gold® Natural & Organic Potting Mix to meet the demands of your container crops from start to finish. Some experts also advocate filling container bottoms with dead (not green) lawn sweepings or compost, such as Black Gold Natural & Organic Compost Blend, and then following that with a foot or more of potting mix.
  6. Plan ahead for weekly care. Smaller gardens need less care, but you will still need to water, weed, feed, and harvest regularly. Plan a care schedule for each week. Be most conscientious of container plants because they are especially subject to drying and nutrient loss.
  7. Plan to replace crops. Some crops, like beans, greens, and root vegetables are fast-growing. Determine their days to harvest (click here for a harvest guide), and plan to replace them once they are picked or no longer productive.

Vegetables for Small-Space Gardens

Tomatoes

Tomatoes generally grow best in larger lots because they need lots of root space, and they have greater water and nutrient needs than most other vegetables.

Choose compact bush (determinate) or semi-bush (semi-determinate) tomatoes for small-space raised beds and pots. Super small pot tomatoes include the disease-resistant cherry tomato ‘Sweetheart of the Patio‘ (24-36″) and salad tomato ‘Patio Delight’ (12-18″). Larger determinate tomatoes for caging or staking including the flavorful, red, slicing tomato ‘Celebrity’ (36-40″), the early beefsteak ‘Galahad‘ (24-36″), and golden sauce tomato, ‘Sunrise Sauce‘ (24-36″).

Planting recommendations: plant one plant per 5-gallon container. Cage or stake plants reaching 18″ or more. Manage tomato growth by cutting back excessive vining stems once they start really growing. (Click here for more tomato pruning guidelines.) Feed tomatoes regularly with a fertilizer formulated for tomatoes.

Cucumbers 

‘Spacemaster’ cucumbers have short vines and tasty cukes. (Image thanks to Burpee Seeds)

Slicing cucumbers have now been bred in compact form for pots. The most notable variety is the tried and true, ‘Spacemaster‘. The variety has diseases-resistant vines reaching just 26 inches! ‘Bush Champion‘ is another compact variety with vines reaching 24″, and it’s said to produce high yields. Both have medium-sized cukes. Harvest them smaller if you intend to use them for pickling.

Planting recommendations: Plant one or two plants per 5-gallon pot. The seeds can be directly sown into pots. A small trellis can be used if desired. Feed and water regularly, just as the potting soil begins to dry, or the plants will not bear fruit.

Green Beans

Bush beans, green, wax, or filet, are ideally suited to large-container planting. Some varieties are prolific bearers with excellent flavor. Four to five plants are needed per 5-gallon pot. Avoid overfeeding. Beans are legumes and need no extra nitrogen. Beans use a lot of moisture so use a potting mix with good water-holding capacity and water regularly. Several quality varieties

Sweet Peppers

Choose compact peppers for container culture. Their final pot should be larger than the one shown (3 gallons or more), if they are to truly thrive.

New sweet peppers are being bred for small fruits and compact plant size. The lunchbox snacking peppers are most notable. Grow them all, orange, yellow, and red, with the Lunchbox Pepper Mix. The pepper plants reach 28-36 inches and produce lots of sweet peppers.

Planting recommendations: One plant per 3-gallon pot. Transplant starts after the threat of frost has passed. They produce best with days and nights become warmer. Fruits can be harvested green, but I like them best if allowed to reach full color.

Greens

Greens of all types grow beautifully in pots or small raised beds.

Nothing tastes better than greens in pots, such as spinach, kale, Swiss chard, collards, and various lettuces. For the most part, all are suitable as container plants. Unlike the warmer crops mentioned above, many greens are more cold tolerant and can be started in spring before the danger of frost is past, usually by a couple of weeks. Then the greens can be re-sown in summer (If heat tolerant) or in the fall as temperatures cool. The best greens for summer are Swiss chard (we like the colorful Rainbow Mix), heat-tolerant lettuces, like the heirloom ‘Black Seeded Simpson‘, and beautiful Tuscan kale, like ‘Black Magic‘. Please refer to the video below for planting details. The pots are a good size for growing lots of greens!

More small-space gardening reading and information:

 

Five Ways to Maximize Small-Space Vegetable Gardens

Celebrating Colorful Coleus

Coleus ‘Henna’ is a real color-filled beauty with shades of green, orange, and purple.

Long ago, Coleus had been considered a house plant. I can remember, my grandmother always had coleus growing in her house. It was a popular winter houseplant because the colorful leaves provided bright spots of color during the long Midwest winter months. Only occasionally were plants planted outdoors during the summer. My, how the times have changed!

Today, coleus varieties have been developed to be sun tolerant and the leaf colors, shapes, and plant habits are widely diverse. While coleus is technically a tender perennial down south, for most of us they are grown as summer annuals and provide wonderful leaf color throughout the season. The plants need warm weather to thrive and cannot withstand frost, but from late spring until the first frost of fall, they look lovely.

Selecting Coleus

The Proven Winner’s Coleus El Brighto glows in a porch garden filled with cannas, sunflowers, colocasias, and lantanas. The coleus flowers were pinched off after the photo was taken! (Image thanks to Mike Darcy)

When selecting garden coleus, a good rule is to set them out at the same time tomatoes are planted. Both coleus and tomatoes need warm weather, and cold weather can stunt or kill plants if set out too early. Even though some new coleus selections have been developed as sun-loving coleus, I have found most perform better in my garden with some afternoon shade.

Coleus are ideal in both the garden and containers. More compact varieties make superb container plants with their colorful foliage throughout the summer season, such as the new compact, red, purple, and green Coleus ‘Spitfire’. Another I have grown both in a container and the garden is Proven Winner’s showy, ColorBlaze® El Brighto, with its brilliant fringed leaves of red, purple, and gold. (Click here to admire more of Proven Winner’s Colorblaze Coleus.)

Whatever coleus I choose, my potting mix of choice is Black Gold Natural & Organic Potting Mix. It holds moisture well and also provides for good drainage. I add an organic fertilizer at the time of planting and mix it well into the potting mix.

Planting Coleus

Coleus ‘Spitefire’ has a unique layering growth habit suited to containers and hanging baskets. (Image thanks to Mike Darcy)

When setting out and growing coleus plants, it is a good idea to pinch the tips of the stems often to encourage a compact growth habit and encourage branching. Sometimes plants will send up spikes of white or lavender flowers. Even though bees like them, coleus foliage looks best if you pinch off the buds before they bloom. Pinching will stop flowering and encourage the plant to produce new colorful growth rather than flowers and seeds.

Sometimes one color plant can create a nice ‘pop’ of color. Last year I planted Coleus ‘Campfire’ with its amber-orange foliage, and it stood out nicely against a background of green (image below). Another bold coleus with only one color is Proven Winner’s Lime Time, which provides a beautiful display of chartreuse leaf color and is especially nice in a shady area. It mixes well with ferns in a woodland setting,

El Brighto is equally suited to container plantings. The container shown has three plants planted in early June and the photo was taken in mid-August. One plant would have been enough. (Image thanks to Mike Darcy)

Last summer, I saw a pot of Coleus Spitfire in a garden and was impressed. The variety has a unique layering growth habit as well as brightly colored leaves. It looked beautiful in the container and would work equally well in a hanging basket or a garden edge.

Caring For Coleus at Season’s End

The warm, glowing leaves of ‘Campfire’ look attractive against bright greens and golds. (Image thanks to Mike Darcy)

As the summer season ends consider overwintering a coleus. You can either take a cutting to pot up or transplant the larger specimen. They root easily in water and once rooted, can be planted in a small pot and kept by a window for necessary light. (Click here for video details on how to take cuttings.) The plants will probably have to be pinched often as they reach for light, but they are easy to keep over and then planted outside in the spring.

The selection of color combinations is vast and every year there are new forms on the market. Some dwarf types have small leaves and only grow up to about 12 inches. Then there is the Kong series with leaves reaching up to 8 inches in length! If you have not checked out the coleus section at your local garden center, you will be surprised at the diversity of leaf colors and shapes that are available.

Lime Time will brighten up any bed or potted planting. (Image thanks to Mike Darcy)

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!

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