By Dr. F. Todd Lasseigne Executive Director To me, one of the joys of visitors…
The garden in winter: Advice for adding variety and color
By Dr. F. Todd Lasseigne, Executive Director
Winter, from a gardening viewpoint, refers to the time when most plants are dormant. However, gardening in the winter months, and selecting winter-interest plants, is a key part of the Southern gardener’s routine. It is relatively easier physically to garden in cooler weather, and the flowers that bloom in winter tend to last longer, because pigments break down faster at high temperatures than they do in lower temperatures.
The southern U.S. is particularly suited for winter gardening because its winters can be characterized as mild but punctuated by cold temperatures. In other words, it’s not consistently cold or frigid for days on end. We do not have to contend with consecutive days where the temperatures are below freezing.
When you’re selecting plants for your winter garden, be sure to consider several factors, including the shape of the plant; when it bears fruit or flowers; the plant’s winter foliage; the colors of the plant’s bark and twigs; and when the plant sheds its foliage.
Plant form: This refers to the shape or overall architecture of a given plant. For example, many conifers are pyramidal, and many live oaks are broad and spreading. Examples include Deodar cedar (Cedrus deodara) and China fir (Cunninghamia lanceolata), which have a pyramidal form; Curly-leaf Ligustrum (Ligustrum japonicum ‘Rotundifolium’), an upright to oval form; and Evergreen Solomon’s seal (Disporopsis perneyi), which has a mounding form with pendent growth tips.
Bark and twigs: The color or texture of bark and twigs can be a defining feature of some plants in the winter. “Twig” refers to the stem growth on a plant from the current year, and sometimes also the prior year. All older growth is just called a “stem.” Twigs often have colored or textured bark that older stems no longer bear. The Coralbark Japanese maple (Acer palmtum ‘Sango Kaku’) is an outstanding cultivar of Japanese maple that bears beautifully colored twigs, reddish-pink to salmon-pink in color. To achieve maximum effect, prune plants back to stimulate more twig growth (even though some people incorrectly assert that you are not “supposed” to prune Japanese maples). Other plants have interesting winter bark, such as Water elm (Planera aquatica), an obscure native tree with gently flaking bark; Parsley haw (or parsley hawthorn) (Crataegus marshallii), a rarely-seen native tree with beautiful smooth bark that exfoliates in jigsaw-puzzle shapes; and the Japanese snowbell (Styrax japonicus), which can bear smooth, sinewy textured bark.
Winter fruit: Some plants bear fruit that last into the winter. These can be really showy and add color and interest to your garden. Consider planting deciduous hollies such as winterberry (Ilex verticillata cultivars) or possum-haw (Ilex decidua cultivars). The latter is better suited to the Gulf Coast region and is native. Remember that all hollies need a male pollinator plant in order for the female plants to bear fruit. Another good winter-fruiting plant is the Sacred lily (Rohdea japonica), an evergreen groundcover-like plant related to Aspidistra but with showy clusters of orange-red fruits; it’s tough and adapted to the region. A less common selection is the Sweet-box (Sarcococca confusa), a low-growing evergreen shrub with beautiful black fruits and sweetly fragrant flowers. Yaupons (Ilex vomitoria) are a familiar component of southern Alabama woodlands, to the point that they can form thickets. However, female plants do bear attractive fruits, such as the orange-red cultivar called ‘Virginia Dare’. Grow them in your gardens for wildlife value and for ornament.
Winter foliage: Not all evergreens are equal, and not all of them have equally attractive foliage. Look for interesting variegated leaves and interestingly shaped leaves. Variegated abelia (Abelia x grandiflora ‘Hopley’s) is one of many variegated abelias that brightens up a shady corner. Variegated Pampas grass (Cortaderia selloana ‘Silver Comet’) is a beautifully variegated version of a common plant. Each leaf is bordered with a white stripe on either side of the long leaf blades, not as noticeable from a distance as when viewed up close, but still beautiful. Variegated curve-leaf yucca (Yucca gloriosa ‘Variegata’) is a beautiful native yucca with evergreen leaves, the center of the leaf blades variegated, and plants often tinging pink in the winter months. Wild-ginger (one of many species of Asarum, incorrectly referred to as Hexastylis by U.S. botanists) is an evergreen groundcover with heart-shaped leaves. It’s also sometimes called “little brown jugs” because of the shape of the unusual flowers. Tree ginseng (Dendropanax trifidus) is a beautiful evergreen shrub with attractive, 3-lobed leaves, perfectly hardy in our climate. Plum-yew (Cephalotaxus harringtonii ‘Prostrata’) is one of several plum-yews that grow so well in the southern U.S.; as an added bonus, they are virtually deer-proof and can tolerate some salt spray.
Palm sedge (Carex phyllostachya) is one of a huge plethora of evergreen sedges (many are native, but there are also lots of Asian species with plenty of garden value) that add a unique texture to the winter landscape. Spicebush (Lindera aggregata, formerly known as L. strychnifolia) is one of many Asian species of spicebush, with beautiful teardrop-shaped leaves; unlike the native deciduous species of spicebush we have in Alabama, this one is immune to “laurel wilt” disease. The Swamp palmetto (Sabal minor) is probably taken for granted here because of its commonness in the wild, but it’s a wonderful, stemless palm that bears bold leaves that contrast beautifully when set against fine-textured plants, such as grasses. Hardy cyclamen (Cyclamen coum and others) is a great choice because, unlike the frost-tender florist’s cyclamen you see around Valentine’s Day, this and other species are fully hardy for our region. And if you’re looking for something truly unique, consider the variegated loquat (Eriobotrya japonica ‘Doka’), which was brought back to the U.S. from Japan by several U.S. nursery owners in the 2000s. This plant is still undeservedly rare and features beautiful white-variegated foliage.
Winter flowers: Some plants come into bloom when the temperatures drop and a few mild freezes stimulate them into early flower production. There are many less-commonly known species of camellias that should be tried in our gardens, such as mock-orange camellia (Camellia euryoides) with its small white flowers that dangle underneath the branches. I also like Witch-hazel (Hamamelis species and cultivars); although the Chinese x Japanese hybrid witch-hazels are the best known ones in the nursery and garden world, there is a
relatively recently discovered species (Hamamelis ovalis) that is native to southern Alabama, southern Mississippi, and southeastern Texas that bears much promise as a heat-tolerant and “low-chill” requiring witch-hazel for southern gardens. Stay tuned for more on this plant as Bellingrath acquires clones and begins to trial them in our gardens. The Flowering quince (Chaenomeles cultivars) is a wonderful deciduous shrub I would not garden without, even despite its brief window of bloom; cultivars can be red to red-orange to white to pink. The Winter jasmine (Jasminum nudiflorum) is a deciduous, winter-flowering true jasmine. It’s absent from Gulf Coast gardens but grows readily just barely inland from us, so it’s worth trying for its green twigs in winter, which are bespeckled with bright yellow flowers through the winter months. Hellebores or Lenten roses (Helleborus x hybridus) produce beautiful pink to white to purple-red to yellow to slate-purple flowers in the dead of winter. This hybrid group may not be the best adapted for the Mobile area but should be tried. The “Mediterranean” hellebores are an entirely different group of hybrid hellebores with gray-green, mottled evergreen leaves and gray and purple flowers. The plants in this group of hybrids are native to the Mediterranean area and do not require cold winters in order to bloom or emerge in the next season. Bellingrath needs to do some trial work with these to see which ones will grow in our area. Consider the Hoop-petticoat daffodil (Narcissus bulbocodium and other related species), unusual daffodils from southern Europe, the Mediterranean area, and north Africa. They seem to grow well in the southern U.S. as long as they are given good drainage and sunlight. The Giant pussywillow (Salix “chaenomeloides” or Salix ‘Winter Glory’) is a Japanese pussywillow that bears huge male flowers (catkins), almost 2” long, covered in long, soft hairs. Cut this one back to the ground in late winter after bloom if it gets too large.
Winter flowers that are fragrant are the best of all worlds! Winter honeysuckle (Lonicera fragrantissima) grows as a semi-evergreen plant here, but is deciduous further north. The almost wax-like, small flowers seem like they can’t possibly produce such copious amounts of sweet-scented delight, but they do. The Sweet box (Sarcococca confusa), mentioned earlier for its shiny, black berries in winter, is even better later for the tiny but powerfully sweetly-scented flowers. Japanese andromeda (Pieris japonica) – a wonderful plant related to blueberries, but with sweetly-scented flowers (depends on the cultivar, though, as to how scented). Try the Taiwanese types for better heat tolerance. Fragrant wintersweet (Chimonanthus praecox) is a winter-blooming, large shrub I would not garden without; its flowers can be a vibrant yellow or a dull straw-color, but they are always fragrant in midwinter. For the rest of the year, it is a back-of-the-border plant with no showy aspects. It’s related to our native sweetshrub (Calycanthus floridus), which flowers in spring. Edgeworthia or paper-bush (Edgeworthia chrysantha) is a plant that deserves to be in every southern garden. It is grown as either a mounding shrub or a limbed-up small tree-like shrub, and produces large clusters of white and yellow pendent flowers in winter, sweetly perfuming the garden. The Japanese flowering apricot (Prunus mume cultivars) is a great winter-flowering tree, related to the true apricot of commerce, and also to flowering cherries. The flowers do not open all at once, which means that if a freeze damages or destroys some of the blooms, there are other unopened ones to follow, unlike cherries that tend to flower all at once. Bobby Green has selected a more heat tolerant one (at Mobile Botanical Garden) which does not exhibit “leaf roll,” a symptom of heat stress. It produces pink to white to fuchsia-pink flowers.
Winter daphne (Daphne odora ‘Aureovariegata’ and ‘Aureovariegata Alba’) is the queen of the winter. This evergreen, low-growing and slow-growing shrub produces terminal clusters of pink or white flowers that will perfume an entire room. It is a finicky grower, often dying for no reason (which I call “sudden daphne death”). Give it good drainage, but do not allow it to dry out, and do not waterlog it. My mom grew it in Thibodaux, La., for years in a container on the back porch near the door into the house. Buy a plant each year, and you’ll never not have it!
Here are some of my recommended online mail-order nurseries:
Nurseries Caroliniana: nurcar.com
Woodlanders Nursery: woodlanders.net
Plant Delights Nursery: plantdelights.com