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Viburnums For Any Landscape

Right: bright red Viburnum opulus berries, do droop. They also feed hungry songbirds.

What exactly is a Viburnum? Viburnums are trees or shrubs, evergreen or deciduous, that may be diminutive three-foot globes or grow 60 feet tall. Their leaf texture varies from smoothly shiny to velvety, and, their leaf edges may be serrated, dentate, lobed, or not! Viburnum flowers are either round or flattish and range in color from white to pink. The blossoms are either deliciously fragrant, have absolutely no scent, or can be downright offensive. Just forget trying to determine what viburnum you are admiring by its fruit color alone since berries range from yellow to orange, red to black, and blue to purple.

According to the great Georgia plantsman, Dr. Michael Dirr, their characteristics are simply too varied to make a definitive identification without a very good reference guide. In his 2007 guidebook, Viburnums, Flowering Shrubs for Every Season, by Timber Press, Dirr admits that even taxonomists can’t agree on how many species presently exist in the genus Viburnum with the true number probably falling somewhere between 160 to 250.

What makes a Viburnum a Viburnum?

V. Carlesii - Photo by Pam Beck
The Koreanspice bush, V. carlesii, provides a perfect example of a viburnum’s opposite leave arrangement.

Famed tree and shrub specialist Michael Dirr’s definition is:

  1. The fruit is a drupe, generally ellipsoidal, flattened, ovoid to rounded, with a fleshy coat, hard bony endocarp, and a single seed within; and
  2. The leaves are always arranged opposite; a few species, occasionally, have three leaves at a node.

Growing Viburnum

Viburnum diltatum (Image by KENPEI)

Besides their exquisite beauty, the main reason why we embrace viburnums in our home landscapes is their extreme hardiness. Many varieties can be very drought tolerant (once established) as some of our best Southeastern native viburnum hail from dry woodlands. A few, such as our native Arrowwood, will also tolerate wet feet. Most will grow well in full sun to part shade, can take a variety of soil types, and still thrive.

Planting Viburnum

In the absence of good soil, you could amend the planting hole fill dirt with Black Gold Garden Soil for improved drainage that will still provide enough moisture retention essential for a newly transplanted viburnum. Otherwise, mulch the base of your new addition with Black Gold’s Garden Compost Blend in order to help hold moisture, keep developing roots cool in summer and warmer in winter, and to suppress weeds.

Great Viburnum

In my home landscape, I have found several species of viburnum grow well under the canopy of a large Black Walnut tree, where it is very dry. Here I have planted Koreanspice bush (V. carlesii) and Cranberry viburnum (V. opulus), and they both perform beautifully.

Viburnums have also been evaluated for their resistance to deer grazing. The toughest survivors of deer predation are our native Arrowwood (V. dentatum); Blackhaw (V. prunifolium); Smooth witherod (V. nudum), which is sometimes erroneously called “possum haw” and, the Maple-leaf arrowwood (V. acerfolium).

Koreanspice Viburnum

The flowers of Koreanspice viburnum are so fragrant. (Image by Bouba)

Koreanspice viburnum (V. carlesii, Zones 4-7) is one of our most popular, old-fashioned, pass-along southern shrubs. Grown for its intensely sweet springtime fragrance, the late March to early April flowers of Koreanspice begin pale pink, turning white with age, grow 2-3 inches across, and are rounded. This 8-10 foot tall shrub has dull green leaves that turn reddish in the fall, and red to black fruits.

Cranberry Viburnum

Cranberry viburnum is named for its brilliant cherry-red fruit clusters that begin coloring in late summer. The popular double-flowered variety ‘Roseum’ is sterile and bears no fruit.

The Cranberry viburnum is named for its brilliant cherry-red fruit clusters that begin coloring in late summer. Its famous leaf fall color is much more dramatic in cooler regions where leaves turn gold, red, and burgundy. A very good cultivar is V. opulus ‘Compactum’, which should top out at just 5-6 feet.

Chinese Snowball

For sheer drama, nothing compares to the Chinese Snowball (V. macrocephalum). This multi-trunked small tree can reach 12-feet or more in height and grow just as wide. Sometimes semi-evergreen in mild winters, this very dark-leafed viburnum is beloved for its 6-8 inch, rounded, springtime flowers that begin pale chartreuse and age to purest white. They are so beautiful that we can forgive it for not bearing any scent. A significant bonus is that it also flowers again from late summer into fall. Since the Chinese Snowball’s hydrangea-like flowers are sterile, there is no fruit, therefore no unwanted seedlings.

Bodnant Viburnum

Viburnum x bodnantense ‘Dawn’ is an early bloomer with lovely fragrant pink flowers. (Image by Magnus Manske)

Your winter landscape could be delightful including a Bodnant viburnum in it. Viburnum x bodnantense ‘Dawn’ has bright pink, strongly perfumed flowers in late February to early March in my Wake Forest, North Carolina, Zone 7-8 garden. The small, rounded, sweetly fragrant flowers are borne on bare branches on a rather rangy shrub, but ‘Dawn’ blends nicely into the mixed border the rest of the year.

Viburnum Tinus

Garden centers offer V. tinus ‘Spring Bouquet’ in autumn, which is the right time to plant them. During the late fall months ‘Spring Bouquet’ forms tight rose-colored clusters of buds that will start popping open during the first months of the new year. These viburnum flowers are only slightly fragrant, but they will cover the small shrub. This evergreen viburnum will need part shade in summer, winter protection from sun, plus they benefit from being shielded from desiccating winds.

Doublefile Viburnum

Doublefile viburnum (Viburnum plicatum) has lovely tiered branching and should not be pruned.

Since they bloom in early April, Doublefile viburnums, V. plicatum f. tomentosum, are great substitutes for ailing native dogwoods. Named for its flowering habit of doily-flat flowers positioned side-by-side along the top of long horizontal branches, this is a stunning small tree. These viburnum are deciduous in winter, have dark green foliage in summer, and bright red berries in late fall. A cultivar named ‘Summer Snowflake’ will bloom well in early spring, then sporadically repeat off-and-on throughout the summer.

Chindo Viburnum

Chindo viburnum is another popular viburnum that isn’t grown for its flowers at all. Promoted by the late Dr. J C Raulston of North Carolina State University, V. awabuki ‘Chindo’, is a loosely pyramidal-shaped, shiny-leafed, evergreen shrub that can reach 15-20 feet. It grows in sun or shade and is shaped reminiscent of a large-leafed holly, so it makes an ideal screening plant. One warning is that a Chindo viburnum won’t like winter temperatures that drop below zero; so, if it does get that cold you may have to trim your plant back severely in springtime to encourage new growth to flush.

There is probably a perfect viburnum for just about any location in your landscape, so how do you go about narrowing your selections? Ask your garden center professional for their recommendations, check with your local Cooperative Extension Service, and find a copy of Dirr’s Viburnums book.

 

V. awabuki ‘Chindo’ - Photo by Pam Beck
The ‘Chindo’ viburnum is an outstanding evergreen screening shrub. (Photo by Pam Beck)

When is the Best Time to Plant Lettuce in California?

When is the Best Time to Plant Lettuce in California?

“When generally is the best month to start lettuce planting [in California]?” Question from Rebekah of Clovis, California

Answer: Lettuce is a cool-season crop, which means that it thrives in cool weather and can even take a light frost but not hard freezes. When the weather becomes hot, most lettuce varieties quickly become bitter-tasting and set seed (bolt).

Based on the Clovis climate summary, your weather remains cool enough for lettuce from October through to April or May. Within this time, you should be able to grow more than one crop. Just be sure to grow it in fertile soil and keep the beds well irrigated during dry weather. We recommend drip irrigation for dry California climates. (Click here to learn about adding drip irrigation to raised beds.)  If you anticipate an unexpected frost, cover your plants with frost cloth.

Clovis, California Climate Summary

I encourage you to watch the following video about the 10 best lettuce varieties and how to grow them from seed.

 

Happy lettuce growing,

Jessie Keith

Black Gold Horticulturist

Hellebores for Late Winter Color

It has been unseasonably cold here in the Pacific Northwest. In Portland, Oregon, we have had temperatures down in the teens, which is not the norm. To make matters worse, we had an extended period when the temperature did not get above freezing. The ground is very dry, which causes additional stress on plants when the ground is frozen. Walking out into my garden this morning, I must say it is looking very bleak. The Eugene area has had some snow, which is a good insulator that offers cold protection for plants, but the Portland area has not had any significant snow. Our ground is bare and dry. Nonetheless, the hellebores are beginning to show themselves.

However, we have many benefits to be living and gardening here, and one is the hellebore (Helleborus spp.), which is a true winter gem. Most are hybrids of the winter-blooming Christmas Rose (Helleborus niger) and later, midwinter- to early spring-blooming Lenten rose (Helleborus orientalis). All can withstand the cold, wind and rain and not only survive, but thrive. It is also one plant that I have heard deer will not eat. Hellebores were very popular in the Midwest in the early 1900s, and then their popularity diminished. In the early part of this century, they made a resurgence and have become increasingly popular in Pacific Northwest gardens. Plants are being bred to have stronger stems and an ever-increasing palette of color.

 

The Best Hellebores

Hellebore 'Double Painted'
The glorious hellebore ‘Painted Double’ is one of many outstanding selections in the Winter Jewel™ Series.

Hellebores should be on every gardener’s must-have perennial list. Their most outstanding attribute is that they bloom in winter when most other perennials are sleeping the deep sleep, but their evergreen foliage is also a nice, year-round bonus. When planted in masses, they even make a nice groundcover. Even novice gardeners will find these shade-lovers easy to grow. They’re even deer-resistant.

As I write this column in early December, there are flower buds beginning to show their color on some of my plants. I have seen hellebores even blooming in the snow in January. A particular variety that has been outstanding in my garden, called ‘Jacob Classic’,  is from the Gold Collection®. This is an early bloomer with white flowers that tend to face forward instead of downward, as many Hellebores do. It will begin flowering in January and continue for at least two months. It makes an excellent container plant, especially by an entryway, as the early blossoms provide winter cheer.

Another group of hellebores is the Winter Jewel™ Strain. The flowers in this series provide some apricot, yellow, white, and rose-red bloom colors that are relatively new for hellebores. I have two of these that have performed will in my garden and provide some striking winter color. These are ‘Painted Double’ and ‘Golden Sunrise’. As the name implies,  ‘Painted Double’  has double flowers of white with rose-red speckles that look painted. The cheerful ‘Golden Sunrise’ has ruby-edged single flowers that turn slightly downward to reveal the soft yellow backside of the petals.

Growing Hellebores

Hellebore 'GoldenSunrise'
Ruby edges bring radiant color to the nodding, primrose-yellow flowers of hellebore ‘Golden Sunrise’.

 

Hellebores like to be planted in soil that is rich in compost, such as Black Gold® Garden Compost Blend. They also perform better when given some shade from the hot afternoon sun. Hellebores make excellent plants for under a large tree where they can benefit from the filtered light that falls from between the branches. Once established, they can become a permanent part of the garden and require very little maintenance.

Hellebores aside, many Pacific Northwest gardeners successfully grow plants that are considered marginally winter hardy. With our past relatively mild winters, many have survived with minimal protection. This winter is sure to prove which plants are marginally winter-hardy and which are not. In my garden, I have a Gunnera tinctoria that I consider marginally winter hardy. Luckily, several weeks ago, I mounded the crown with Black Gold Garden Compost Blend, and then on top of that I placed the huge Gunnera leaves that I had removed from the plant. The Gunnera leaves will help keep the conditioner from blowing away in the wind. Hopefully, this method will provide the insulation the plant needs to survive. I have done this in winter’s past, and it has worked.

Hellebore 'Jacob'
Clear white flowers with bright yellow stamens grace hellebore ‘Jacob Classic’ in winter.

With the weather as cold as it’s been, there is not much a gardener can do to protect plants without a protective greenhouse or sunroom, though I always have a few tender plants that I put on a garden cart and take into my unheated garage. (My prediction for this spring is that garden centers will see a surge in sales when spring finally arrives with gardeners buying plants to replace those that couldn’t take the cold.) In the meantime, get into the spirit of this season with a visit to your garden center, and check out the holiday displays, which are certain to include a few choice hellebores.

DIY Garden Project: Birdseed Ornaments for Outdoor Decorating

Bring living beauty to your winter garden with these three do-it-yourself birdseed ornaments for outdoors. Each project is a great activity for kids. Some wild birds just eat seeds, while others rely more on berries, and some need fat, like suet, to survive winter. Our different ornaments have ingredients to satisfy almost all wild winter birds. These ornaments fulfill the diets of many different birds.

Click here for a step-by-step pdf.

Rosemary Is For Winter and Gifting

Fill pretty, recycled jars with freshly-dried rosemary for holiday gifts for foodies (and pet lovers too, see below).

When I first came to the Southern California desert, I was shocked at how well traditional rosemary (Rosmarinus officinalis, USDA Hardiness Zones 8-10) shrubs survived through 120ᵒ F summer days. When provided good drainage and some water, these plants thrive in dry, mild-winter locations and reach mammoth proportions. If fragrant, culinary rosemary is able to thrive in low-desert heat and naturalize along the West Coast, it should grow well in practically every garden where it’s hardy. There isn’t a more useful plant for arid-zone landscaping, but rosemary also fares well as a potted plant where winters are cold.

Rosemary History and Uses

When in bloom, rosemary is showy and attracts bees. (Image by Maureen Gilmer)

Rosemary is native to the Mediterranean and parts of Asia. It has a long history of use and cultivation going back thousands of years. Grown wherever possible outdoors in mild areas, whether as an ornamental or herbal plant, it has also been traditionally cultivated in pots in colder winter regions and brought indoors to shelter. As a house plant, rosemary can be clipped with scissors to release its scent, just as the Romans did to perfume their courtyards naturally. Greeks believed wearing sprigs of rosemary in the hair while studying assisted with memory, hence the plant’s perpetual association with remembrance. And, during the plague years, rosemary was burned as a disinfectant much like white sage smudge sticks have been used in the Americas for purification.

The sheer range of uses for rosemary should make everyone want to grow this easy and willing plant. It is above all a culinary herb, and foodies often use the straight twigs for savory beef or lamb kebab sticks or sprigs to naturally flavor roasts. As the leaves are heated, they release their plant oils. Rosemary may also be used to flavor olive oil, teas, and is an essential ingredient in many classic herbal mixes, such as Herbe’s de Provence, a provincial herbal mix from southern France. (Click here for a Herbe’s de Provence recipe and to learn more about classic French herbs.)

Rosemary has also been traditionally valued as a hair tonic. The Romans, being largely dark-haired, used it to create a hair rinse brewed with water and then cooled. It was poured on dark hair to cut residual soap accumulation and left hair shiny and beautiful. Blondes used the same technique with Roman chamomile (Anthemis nobilis).

Rosemary Types

Creeping rosemary loves to dangle off the edges of raised beds. (Image by Maureen Gilmer)

Rosemary averages 4 feet at maturity but can reach 6 feet tall in its natural, rocky, sunny habitat in the Mediterranean. Its narrow leaves become more silvery and needle-like in dry weather and greener and broader when rain is plentiful. Pale violet-blue flowers that attract bees may appear from midwinter to spring.

There are two basic forms. The standard or “official” form from the old herbals is Rosmarinus officinalis. Hardy to 10 or 20° F, it’s a long-lived evergreen shrub for mild-winter regions and often used for landscaping. The shorter variety, Rosmarinus officinalis ‘Prostratus’, develops a low mat of graceful, cascading foliage. Growing to about 1 foot tall, with almost an infinite spread, there is no better cascading plant for pot, slope, cliff, or wall. Its dark tresses are incredibly tough and prefer more shade than the upright type. It works well as a house plant due to having a shorter stature. There are named varieties of rosemary of varying sizes and flower colors, some are even hardier (the variety ‘Arp’ is touted as being hardy to Zone 6), so there’s one for all different sunny gardens.  Everyone else can treat it as a house plant that comes outdoors for the summer.

Growing Rosemary

Rosemary makes fine topiary standards, often sold at florists in the city or by special order. (Image by Maureen Gilmer)

Grow potted rosemary in a mixture of equal parts Black Gold Natural & Organic Potting Mix and Black Gold Cactus Mix to avoid overly damp conditions that cause root rot in arid-zone hill plants like these. Make sure there’s a big drainage hole or many small ones because rosemary must have fast drainage to avoid fungal infections that also plague lavenders, which like the same growing conditions.

There is no easier drought-resistant, long-lived herb, shrub, or useful plant to grow for home and garden that will make you feel like a pioneer woman. Rosemary is one plant that can teach you much about the cultivation of useful herbs. From a woman with a self-sufficient, pioneering attitude, a novice can learn hands-on how to harvest and prepare herbal material to use in the household and to make really fragrant gifts for family and friends.

Eight Simple DIY Rosemary Crafts

Decorate a freshly wrapped gift with aromatic rosemary sprigs tucked into the ribbon.
  1. Put freshly dried rosemary into tied cheesecloth bundles to season soups and stews.
  2. Place sachets filled with rosemary into drawers to scent linens and clothes. (Rosemary’s non-floral scent makes men’s clothing smell pleasantly herbal.)
  3. Fill pretty, recycled jars with freshly-dried leaves for holiday gifts for foodies (and pet lovers too, see idea 8).
  4. Stud pomanders with short rosemary sprigs and place them on a mantel or tree for scent and beauty.
  5. Create small wreaths or herbal swags with creeping rosemary sprigs for hanging indoors or out. (Once the leaves are dry, collect them for cooking.)
  6. Decorate a freshly wrapped gift with aromatic sprigs tucked into the ribbon.
  7. Infuse olive oil or fine vinegar with fresh-cut rosemary sprigs for a culinary gift.
  8. Grind dried rosemary leaves and scatter in pet beds to battle odors and discourage ticks and fleas.

If you live where rosemary does not thrive year-round, buy a rosemary topiary to grow indoors, or invest in a potted 1-gallon rosemary to decorate for the holidays. Both will provide super fresh culinary clippings. Enjoy the indoor plants through the new year, then move them outdoors when temperatures warm up. And, where it’s mild year-round, plant your garden with lots of rosemary, so you have plenty of “mother” plants to snip and clip for the rest of your life.

Rosemary averages 4 feet at maturity but can reach 6 feet tall in its natural, rocky, sunny habitat in the Mediterranean.

How Do I Keep My Evergreen Wreaths and Garlands from Drying Out?

“Every year at the holidays, I hang a live wreath and real pine garland on a fence outside near my patio. I’m wondering if you know of a way to preserve both the wreath and garland so that they last beyond the holiday season without getting brown?  Thank you!” Question from Diane of Newark, Ohio

Answer: You have a couple of options, use either evergreen preservatives or foliage sealers. For preservatives, you can purchase one or make your own. Then there’s a matter of getting it into the wreath and/or garland branches. Liquid preservatives are easy to get into wreaths but next to impossible to get into long garlands unless the greens were preserved beforehand. For garlands, foliage sealer sprays are the better option, though they are a bit more expensive, especially if your garlands are long. Either way, here is an overview of different preservative products, application options, and suggestions for use.

Commercial and DIY Evergreen Preservatives

Chemical Tree Preservatives

There are many bottled commercial evergreen preservatives available. Look for them wherever cut trees are sold. There are also DIY recipes for evergreen preservatives that are said to be quite effective, though I have never tried one myself. Here is a DIY evergreen preservative recipe that I obtained from Live Science (click here). It provides clear step-by-step details. Keep in mind that all chemical options are toxic, so when using them, make sure pets or children cannot access the water. (Click here for additional safety instructions for evergreen preservatives.)

Wreath preservation: Shortly after purchasing your wreath, fill a broad utilitarian pan large enough to accommodate your wreath with the recommended preservative-to-water ratio. The pan should be filled with at least 2 inches of the mix–enough to cover the branch bases. Next, cut the branch bases with sharp pruners; this will allow the preservative to be taken up. Next, submerge the back of the wreath in the preservative mixture. Set the preserving wreath in a cool, dark place for at least a few days. Allow it to dry before hanging. This should help your wreath last longer outdoors. As a double precaution, you may also spray it with sealer.

Glycerin

It takes time to successfully treat evergreens with glycerine–two to three weeks–but if you have time, give it a try. Glycerine is non-toxic and available at craft centers. To make the mix, pour one part glycerin and two parts water into a pot. (The final quantity should be enough to submerge the back of your wreath in a pan.) Next, heat the mixture until it just reaches a boil, and then remove it from the heat. Let it cool, and store it in a cool, dark place until use.

Wreath preservation: Follow the same steps for chemical preservation using your glycerin mix, but keep your wreath in it for at least two weeks. After this time, the needles should be somewhat pliable. You’ll need more time for this method, so be sure to purchase wreaths in advance of the holidays. You can also cut evergreen stems, treat them with glycerine, and then make your own wreath. (Click here to see a great DIY wreath-making slide show by Martha Stewart.)

Spray Sealers

Clear foliage sealers are purchased as sprays and are perfect for helping preserve garlands. They keep needles from desiccating and add a glossy finish. There are also glittery ones if you like that sparkly look. Read the product instructions for the application.

Hopefully, one of these methods will work for you. As a final tip, for Christmas tree care I add sugared lemon-lime soda to the water. Adding a can to around a gallon of water will feed the tree and help keep the vascular tissue open for water uptake.

Happy holidays!

Jessie Keith

Black Gold Horticulturist

Overwintering Outdoor Ceramic Containers

With 150+ potted containers throughout my garden, it is important that I overwinter them well. Living on the relatively mild western slope of Oregon’s Willamette Valley, our winters do not compare with those in colder parts of the country, but we do get freezing temperatures. Almost every winter, we will have some nights when the temperatures dip into the low 20’s and sometimes into the high teens. While we also have our fair share of rain during the winter months, we often get a few days of snow and ice, which can wreak havoc on containers.

Protecting Wintering Containers

This snow-covered Italian Terracotta flower pot will likely weather through the winter.

Plants in containers are exposed to the elements more than those in the ground. Pots do not offer roots as much insulation or protection, but each is different in its protection and durability, whether glazed ceramic, concrete, plastic, Terracotta, or stone.  (In this article, we will cover ceramic pots, which are what I use.) Just like the hot summer sun can quickly dry soil in a container, especially with Terracotta pots, cold temperatures, and winter wind can freeze the soil. The ice expands, and as it does, it often has enough force to crack certain pots, especially if the soil is moist.

The question is, what ceramic containers endure winter cold without cracking? In our climate, it would be very unusual for a container not to have soil wet from the winter rain and then potentially freeze. So, having the right container is an important necessity.

Over the years, I have learned through trial and error what pots work. The conclusions that I have reached are not scientific but based on my own experience in dealing with different types of pottery from different places. Some behave poorly outdoors and are better reserved for indoor plantings.

Pots for Indoor Use

Mexican pottery is fantastically pretty but cracks easily outdoors in freezing winters.

First, bear in mind that some manufacturers add elements to their clay to make pots more winter hardy, and some don’t. Thickness and firing temperature can also help prevent cracking. Generally, I have found that Terracotta-based Mexican pottery, glazed or unglazed, will not survive a cold winter without cracking. Likewise, most pottery from China is variable, but the thin pots tend to crack. Some of the most beautiful pottery that I have seen is from Thailand, but it tends to be thin-walled and is poor for outdoor planting.

Thin-walled ceramic pots tend to crack while thicker-walled pots don’t.

We do have some pots from Thailand in our garden, though. These tend to have unique designs and colors and create much interest from visitors. We use Thai pots as pieces of garden art with nothing planted in them. There are holes in the bottom for the rain to drain through, so there is no concern about cracking.

If you choose to grow summer annuals in pots that are not reliably frost-proof, take out the soil when you remove the annuals. Or, if your containers are mobile, move them into a garage to protect them.

Pots for Outdoor Use

Thick-walled, high-fired Vietnamese pottery survives the winter very well for me.

Containers from Italy seem to go through our winters just fine, but those that consistently weather through without cracking are from Vietnam. In our area, the Vietnamese pots sold in local garden centers are thick-walled, highly glazed and fired, very heavy, and frost proof. I have some pots from Vietnam on our deck that we have had for 15 plus years, and they have never cracked. These pots are exposed to winter winds, rain, freezing; they have no protection from the elements.

Thick, high-fired Italian pottery also withstands winter cracking better.

Another important factor when a purchasing pot is getting the right pot for the right location. Check the selection of winter-hardy pots at your local garden center for colors, sizes, and styles with good thickness, high fire, and thick glaze. I have found that the right colorful containers scattered throughout the garden are permanent additions that also serve as garden art.

Microclimates play a role, too. Try to protect your outdoor pots through winter by placing them below overhangs or patios close to the house. Not only can this further help protect them from cracking, it helps the shrubs or perennials they hold.

I Need Tips for Cold Frame Gardening

“With which of your products does one prep the soil for winter crops in a mini greenhouse, type Cold Frame Mini Green House by Juwel (I just got one)?  It will face South-East.  Any experience growing with this method?  Any easy crop recommendations?” Question from Judy of Yarmouth Port, Massachusetts

Answer: Thank you for your questions. I have gardened in a cold frame and observed successful and unsuccessful cold-frame gardening. In your northern garden, I would place the cold frame in a sunny south-facing spot close to your home. The reflective heat from the house will provide some winter protection, and the warm sun will help heat the cold frame. If you can, I would also recommend sinking the cold frame a few inches below the soil level, even though I see that the frame you have purchased has clear sides. Really good cold frames are set below the soil level to better hold heat in winter. On unexpectedly hot fall or winter days, be sure to prop the top open to keep the internal temperature from getting too hot.

Cold-Frame Soil

As far as soil, I would amend your ground soil at the base of the frame with good compost, like Black Gold Garden Compost Blend, at a 1:2 ratio of soil to mulch. The addition of earthworm castings would also be enriching. The lighter and more fertile your soil, the better your veggies will grow.  Adding a layer of compost as a protective mulch would also be helpful. (Click here to learn more about creating the best soil for raised beds.)

Cold-Frame Vegetables

It is essential to grow cool-season, frost-resistant crops. These are largely winter greens and root crops. The greens that I recommend include mâche, kale, lettuce, and spinach. The best root crops include winter carrots, radishes, and turnips. Parsley and chives are good herbs to try. (Click the following link to learn more about growing winter root crops and click this link to learn more about growing cool-season greens.)

I hope that this information helps!

Happy gardening,

Jessie Keith

What Is the Best Narrow Conifer for Snowy Colorado Landscapes?

Eastern red cedar

“What is a good upright juniper, or other narrow conifer, to plant that stays nice and narrow and tight so snow doesn’t bend the branches down and damage them? My planting area only gets partial sun and is very dry for much of the year. I tried Skyrocket junipers, but they broke under the weight of the snow.” Question from Sharon of Westminster, Colorado.

Answer:  There are quite a few evergreens that can take snow load. The best are natives to your region, but there are also some cultivated, non-natives to consider.

Narrow stature can reduce snow load, but limb flexibility is even more important. Trees with unrelenting, stiff branches suffer the most breakage, while those with flexible branches bend under snow and pop back when the weight is gone. Often, the snow will slip off as the branches bend. Your native limber pine (Pinus flexus) is named for this trait.

Thinking along these lines, I would choose evergreens with good strength, bendy branches, some drought tolerance, and the ability to survive in lower light as young trees. Native selections will likely perform the best. Good options do not have to be linear.

Colorado Native Snow-Resistant Evergreens

  • The superlinear fastigiate Douglas fir, Pseudotsuga menziesii ‘Fastigiata’, is hardy to Zone 5 and has moderate drought tolerance.
  • Rocky Mountain cedar (Juniperus scopulorum), grows to 30 feet and can withstand some understory (partial shade) conditions as well as drought.
  • The Limber pine (Pinus flexus) will reach 65 feet, withstand some drought, and take lower light until it outgrows surrounding trees.
  • The columnar lodgepole pine (Pinus contorta var. latifolia ‘Fastigiata’) and tall, super-tough Ponderosa pine (Pinus ponderosa) are two more options tolerant of the conditions you mention.

Non-Native Snow-Resistant Evergreen Options

  • Prairie Statesman® Swiss stone pine (Pinus cembra ‘Herman’): This alpine tree may not be native, but it is narrow, upright and stands up to snow. It is also drought-tolerant, withstands very cold winters, and reaches 30 feet high and 10 feet wide.  Its bright green needles are very fine.
  • Green Arrow Alaska Cedar (Chamaecyparis nootkatensis ‘Green Arrow’): This is about as narrow as you can get. No snow could hang onto these branches.  Green Arrow is very hardy, reaches 20 feet high and 2 feet wide. These look best planted in a group.
  • Hetz’s Chinese juniper (Juniperus chinensis ‘Hetzii Columnaris’ or ‘Columnaris’): This Chinese juniper is pyramidal, narrow, relatively compact (reaching 15 feet or taller) and provides a good windbreak for very cold areas to USDA Hardiness Zone 4.
  • Serbian spruce (Picea omorika, Zone 4). There are many tall, narrow varieties adapted to high snowfall, but the tree only has moderate drought tolerance.

I encourage you to search out more varieties via the ever-useful Morton Arboretum’s Tree Database.)

Happy conifer growing!

Jessie Keith

Black Gold Horticulturist

Can You Suggest Native Winter Shrubs that Feed Birds?

American cranberrybush (Viburnum opulus var. americanum) is one of several great native shrubs for birds.

“What native bushes (VA) can I plant that will provide winter food for wild birds?” Question from Dagmar of Virginia

Answer: The fruits and nuts of many Mid-Atlantic native shrubs feed birds in winter. Here are some of the best shrubs with fruits and nuts for winter birds.

Native American Shrubs with Fruits for Birds.

Some of the best red-fruited shrubs for birds are winterberry (Ilex verticillata), American cranberrybush (Viburnum opulus var. americanum), and chokeberry (Aronia arbutifolia). The pretty witherod (Viburnum nudum) has berries that turn from bright pink to blueish-purple, and arrowwood (Viburnum dentatum) has deep-blue berries. The vivid purple fruits of American beautyberry (Callicarpa americana) are also lovely and loved by birds. These highly landscape-worthy native shrubs have beautiful winter fruits coveted by many songbirds.

Native American Shrubs with Nuts for Birds.

A good nut-producing native shrub is the American hazelnut (Corylus americana). Plant this large shrub along the margins of any spacious garden or landscape. The edible hazelnuts they produce are just as tasty to homeowners as they are to birds and other wildlife. We also recommend planting sunflowers in the garden. Let their seedheads dry and winter birds will flock to them. (Click here to learn more about nuts for edible landscaping.)

Check out your local garden center for varieties of these shrubs. Most cultivated forms have even more fruits than wild types. Expect the berries to persist from early to midwinter, so you can appreciate their landscape color and wildlife value.

Happy winter gardening!

Jessie Keith