As the Director of the Allen Centennial Garden, a public garden on the campus of the University of Wisconsin-Madison, I’m always on the lookout for plants that extend the season of interest for our visitors. Plants that are hardy, easy to grow and dependable rank high on this list of some of our favorites.
Those That Linger
Plants in this category push the boundaries of what’s possible in the face of hard frosts. These plants thrive in cool temperatures and reward you for keeping them around, despite winter’s imminent arrival.
Left: #1 Pansies, Center: #2 Snapdragons Top-Right: #3 Kale Bottom-Right: #4 Forget-Me-Nots
Most commonly used as an early spring bedding plant, pansies perform just as well (if not better) in autumn through the frosts and light snowfall of early winter. While not a guarantee, fall-planted pansies have a chance to overwinter and start blooming all the earlier the following spring.
Typically thought of as champions of the summer garden, snapdragons are a powerhouse when it comes to delivering color late into the season. The key to their continued flowering is constant deadheading. If the plants are allowed to set seed, they’ll cease flowering. However, this might be desirable in your garden, as snapdragons can reliably reseed for many years in the right space. At the Allen Centennial Garden, we have a red snapdragon that has come back reliably and repeatedly for many years in our rock garden.
A standby of traditional fall bedding plants, kale varieties give some of the best displays when temperatures begin to fall. Both ornamental and edible kales are durable through frost; however, the ornamental varieties tend to be the go-to choice as their purple, red, and white pigments intensify with each cool day. I’ve used ornamental kale in container arrangements through December. Combined with evergreens, Osage orange fruits, golden dogwood stems and a few twinkle lights, kale can make an amazing holiday display.
4. Forget-me-nots and Poppies
The blue forget-me-not (Myosotis sylvatica) and most poppies (Papaver spp.), with the exception of Oriental poppies (Papaver orientalis), are cool-season annuals. Cool season annuals can be direct sown in fall for a jumpstart on an early spring display. These plants will form a tight rosette of growth in fall similar to a mini head of lettuce and then erupt into flower when the garden begins to come alive in mid-April and May. Any of these plants can be sown indoors in February and March and treated as true annuals; however, plants that are fall sown will produce a much more impressive display.
Those That Punch through Snow
Plants in this list don’t waste any time in late winter and early spring – they can’t wait to get up and get growing. Some even create their own heat to melt the snow around them!
Top-Left: #7 Witch Hazel Bottom-Left: #5 Winter Aconite Center: #6 Skunk Cabbage Right: #8 Hellebores
5. Winter Aconite
Without question, winter aconite is my favorite plant in this list. The charming Eranthis hyemalis is one of the earliest harbingers of spring, often pushing up through pockets of melting snow in mid- to late February. Growing only a few inches tall, on warm and sunny days the cheerful yellow buttercup flowers open up and exude a mild and charming honey-like aroma. Growing from small rhizomes that, when dormant, could easily be mistaken for a clod of soil, winter aconite easily naturalizes throughout a garden by reseeding. Seeds mature by mid-May to early June, and with a little help from a gardener, they fall and germinate at the soil surface. Within one to two seasons, these new plants will be blooming and producing seed of their own. After the plant sets seeds, the foliage withers away until the following spring. Winter aconite thrives in a woodland garden or mixed perennial border, and it doesn’t require many rhizomes to start your own colony. Before you know it, you could have a golden ground cover in February that honeybees and other pollinators adore.
6. Skunk Cabbage
Skunk cabbage (Symplocarpus foetidus) is one plant that literally forces its way up through snow and ice. A native plant along swamps, streams and ponds, skunk cabbage is a fascinating plant with an ability to create and regulate its own internal heat, much like any mammal. Maintaining an average temperature of 36 F, it produces this warmth as it metabolizes oxygen and starches stored in its roots. True to its name, skunk cabbage produces a potent odor to attract pollinating flies that are normally attracted to decaying meat. The flowers resemble a sort of mottled purple, red and brown hooded cap. Big, tropical-like leaves emerge following the flower and remain through mid-summer when the plants go dormant until the following spring. While skunk cabbage requires specific growing conditions, its sheer intrigue and unique adaptations make it worth growing to beat the winter blues.
Other Plants that Love the Cold
7. Witch Hazel
If skunk cabbage is the “stinker” of the spring garden, then witch hazel is its sweet, sultry and spicy counterpoint. A deciduous shrub native to North America, Hamamelis vernalis is a truly marvelous plant. Clusters of spider-like flowers cover the stems and bloom January to March. On warm days (30 to 40 F), witch hazel emits a powerful and intoxicating fragrance. The sweet, spicy and sometimes fruity aroma has been compared to baked goods and fruits like concord grapes. Flower color ranges from a strong and pure golden yellow to burnt orange and a deep pinkish red. These multi-stem shrubs appreciate regular moisture throughout the growing season and can tolerate full sun to part shade, making them a great choice for rain gardens and low-lying areas.
One of the classic early spring plants, hellebores come in a range of different colors and bloom types, with new varieties introduced each season. Hellebores straddle two categories on this list – those that push through snow and those that are evergreen. The deep green, palmate, serrated leaves of the hellebore retain their color through winter and into early spring. Each season, new flower buds and leaves emerge from the plant crown, making the old leaves redundant. It’s a personal preference whether or not to remove the old leaves in spring – it won’t do any significant harm or good to the plant beyond vanity. The only real challenge with hellebores is that, despite the incredible diversity and beauty of their flowers, the flowers face downward. If possible, planting them along a shaded wall or raised area will allow you to enjoy the flowers more fully. They also make tremendous cut flowers, allowing you to enjoy them right at eye level on the kitchen table.
Those That Are Always Around
When talking about winter interest and evergreen plants, most of us instinctively gravitate to conifers. Conifers certainly perform an important function in the winter landscape and have earned their rightful place in this category, but there are a number of evergreen plants that can add a new punch.
Left: #9 Oregon Grape Holly Center: #10 Carex 'Ice Dance' Right: #11 White Willow
9. Oregon Grape Holly
A colony-forming shrub, Oregon grape holly (Mahonia aquifolium) truly is a plant for all seasons. Big, bold, glossy, holly-like leaves are evergreen throughout winter and great for use in wreath making around the holidays. Best planted in part to full shade in organic, acidic soil, Oregon grape holly will deliver a show throughout the year. Huge panicles of showy yellow flowers dance on top the stately leaves in spring, followed by clusters of jewel-like, edible blue-black berries in late summer. Plant at least two to three plants in a small colony to encourage optimum fruit set. Single plants likely will not fruit well, if at all.
10. Carex ‘Ice Dance’
Sedges are a rich and diverse genus of plants, and C. ‘Ice Dance’ is a stand out performer for its wide bold leaves, up to 24 inches tall, outlined in white. When planted close together, several carex plants will quickly form a ground cover – a great alternative to traditional ground covers such as winter creeper (Euonymous fortunei). Leaves of this carex are evergreen throughout the winter, and in fact, the plant can suffer (or at least look pretty bad) if cut back in fall or spring. Adaptable to shade and part sun, ‘Ice Dance’ is a versatile and durable plant.
11. White Willow
The common name of this plant really doesn’t do it justice, as the winter stems of this willow are anything but white. A range of cultivars of Salix alba are available; however Salix alba var. vitellina is a standout in the winter garden. Gradation of color from golden yellow to orange to deep red cascade from the base of each stem to the tip. I prefer them to shrub dogwood for this reason as most dogwoods are a single, solid color and lack such a striking color gradient. During the growing season, these plants are fairly unassuming with regular simple green leaves. Winter is when they really “come alive.” For the best display, cutting the stems back to the ground no later than early spring will force a flush of new growth. This not only helps keep the plant under control (willows are notorious for being aggressive); it also provides a great source of material for winter containers, wreath making and more.
A version of this article appeared in Chicagoland Gardening Volume 22 Number 6.
Photography courtesy of Pan American Seeds (photo 1), Ben Futa (photos 2 & 5), Joe Desousa (photo 3), Joshua Mayer (photo 4), Ron Capek (photos 6 & 8), Christopher Tildrick (photo 7), Andrey Zharkikh (photo 9), Midwest Groundcovers (photo 10), and D. Brown (photo 11).