Tidewater Gardening - January 2008

“Bewitching” Flowering Trees in Winter

by

K. Marc Teffeau, Ph.D.

Director of Research and Regulatory Affairs American Nursery and Landscape Association

   The first snowfall of the winter occurred in early December. The light snow provided much needed moisture and some relief for the drought that we experienced this year. I always find it amusing, going to work every day in Washington, how a little bit of crystalline H2O can bring utter chaos to the seat of power of the United States. Multiple accidents, beltway shut-down, gridlock – sounds kind of like Congress these last few months – nothing moving or accomplished.
    Speaking of snow and weather – are we going to have an abundance of snow this winter? Not according to the long-range forecast of the National Weather Service. The National Oceanic and Atmospheric Administration (NOAA) has released their latest winter predictions for the U.S. The forecasters predict that temperatures are expected to be above average in the Mid-Atlantic states and southern sections of the Northeast in response to the long-term warming trend. They say that a strong La Niña occurring in the central and eastern tropical Pacific Ocean will favor drier than average conditions along the Mid-Atlantic coast.
    NOAA weather people do note that snowfall amounts in our area will depend on other climate factors, which are difficult to anticipate more than one to two weeks in advance. It looks like, long range, we will be heading into a drier than normal spring for 2008 which doesn’t bode well for drought-damaged landscapes from last year.
    We know that January is a slow time for gardeners on the Delmarva Peninsula. If we do have a few milder days, you can get out and do some corrective pruning on trees and shrubs– cutting out damaged branches and generally shaping them up. Resist the temptation, however, to excessively prune spring flowering shrubs as they have already set their flower buds for the spring display.
    January is also an excellent time to do pruning on your apple and pear trees in the garden. I recommend that you hold off on pruning peach, plum and apricots, however, until mid to late march because late winter freezes may damage emerging flower buds. You might want to assess winter damage before deciding how much of the branch to remove.
    We can also do some general clean up around the garden – chores that you didn’t get to last fall. If you cut greenery for Christmas decorations, a good use of those swags is as mulch over the perennial beds. Lay them gently over the top to protect the plants and to help reduce the chance of frost heave.
    While the winter landscape can look rather bleak this time of year, it is surprising that we do have some trees that flower during the winter in the Mid-Atlantic area. Witch hazel, Hamamelis spp. and cvs. is a genus of small trees and shrubs that contain five species and close to 100 cultivars, which are native to Asia and North America.
    Considered a large shrub or small tree, they bloom in late fall or late winter, depending on the species, with unique yellow, gold, orange or red flowers. The plant’s height can range from 6 to 25 feet. On the North American continent Hamamellis can be found growing from New Brunswick, Canada, down to Georgia and west to Minnesota, Missouri and the Ozarks.
    These trees are known as witch hazels because, with a little bit of creative thinking, the stringy, curvy petals of its flower are thought by some to resemble a witch’s broom. In addition to the wispy, twisted, ribbon-like appearance, witch hazel flowers are remarkably durable. It is not uncommon for plants in full bloom to tolerate temperatures in the low 20s for several days. Depending on the species or cultivar, the spicy fragrant flowers come in shades of red, yellow and orange. Bloom time ranges from fall to late winter. All are fragrant to some extent, though some selections are so intense that their spicy smell can saturate the calm winter air.
    Other names of the species include “Water-witch,” because dowsers and early settlers would use a Y-shaped branch of witch hazel, known as a divining rod, to find groundwater. A dowser would grasp the forked ends of the branch, holding it out parallel to the ground in front of them. When water was below their feet, the divining rod would bend or “witch” downward, pointing to the location of the underground source.
    A less common name is “Snapping Hazel,” resulting from the unique, rather loud popping sound that its seed pods make as they dry out and literally explode. This novel seed dispersal method can send the witch hazel’s tiny, ripened black seeds flying through the air a distance of up to 25 feet, insuring that there will be less competition with the parent tree after the seed germinates. Then there is the name “Winterbloom” which refers to H. vernalis, H. mollis and the cultivars of H. x intermedia. Their blooms occur January through March.
    Another characteristic particular to this tree species is its flower structure. Its Latin botanical name, Hamamelis, means “together with fruit.” Witch hazels are the only North American tree to incorporate next year’s leaf buds, last year’s ripe seed pods and this year’s flowers all on the same branch at the same time.
    Ever hear of witch hazel tonic? This medicinal concoction is made from oil extracted from the bark, branches and leaves on the native witch hazel, H. virginiana. Native Americans are credited with making this discovery. They, in turn, taught the early settlers of its medicinal properties. The tonic is still used as a treatment for sunburn, skin irritations, dryness and insect bites.
    But it’s not just the unique bloom times or intriguing names that make this plant so attractive. It also has drop-dead spectacular fall color, ranging from a vivid deep yellow to a rich orange-red. Most Hamamelis spp. are hardy in USDA Hardiness Zones 5 to 8 and prefer well-drained, moist, loamy acidic soils. It is drought-tolerant. Used in a variety of ways in the landscape, witch hazels can be effective as specimen trees or in a massed planting in both partial shade and full sun. Flowering is most profuse when they are grown in full sun.
    There are four major types of witch hazel. The common witch hazel (H. virginiana, Zones 3-8), which is native to the eastern United States, presents its faintly scented yellow flowers just as the nearby hardwood trees are losing their autumn leaves. More shrubby and native to Missouri and Arkansas, the Ozark or vernal witch hazel (H. vernalis, Zones 4-8) might be blooming by Christmas in a mild winter. This plant’s yellow-to-reddish flowers are usually the smallest but most profuse within the genus, with a fragrance that ranges from delicate to a bit husky.
    The Chinese witch hazel (H. Mollis, Zones 5-9) and the more delicate Japanese witch hazel (H. japonica, Zones 5-9) flower later. The Chinese witch hazel is always some shade of yellow, broad petaled, and usually sweetly scented. Its Japanese cousin can have yellow or reddish flowers with petals that are narrower, more spider-like, and with a less intense perfume. Chinese witch hazel has fuzzy leaves that turn yellow in autumn, whereas the Japanese variety boasts smooth leaves that turn shades of burning red and orange. In the early 1920s, Boston’s Arnold Arboretum happened upon a cross of the two Asian species, producing hybrids now classified as Hamamelis x intermedia (Zones 5-9).
    There are a number of cultivars of witch hazel available to gardeners. Some of the more commonly recommended ones include H. x intermedia ‘Arnold Promise.’ This is an end-of-season, light-yellow flowering hybrid introduced by the Arnold Arboretum almost 40 years ago. It has a vase shape, is richly scented and usually displays a mixture of yellow, red and orange fall foliage. X intermedia “Barmstedt Gold’ produces modestly scented flowers in a dark yellow that really stands out against an evergreen background. Its petals are more than an inch long and quite feathery, and fall leaf color is yellow.
    If you are interested in red cultivars, there are far fewer of them than the orange or yellow. H. x intermedia ‘Diane,’ is a deep red color which varies in intensity from year to year. Like most red-flowering selections, its scent is very faint. The petals are broad and about 1 inch long. Fall color can be a vivid mixture of red and yellow.
    H. x intermedia ‘Jelena’ is a vigorously spreading selection. Its stunning copper-orange flowers are about 1 inch long. H x intermedia ‘Pallida’ is a low, wide-spreading, early-flowering cultivar. The flowers are paler, larger and more sweetly scented than those of ‘Arnold Promise.’ Their fall color is yellow.
    The U.S. National Arboretum in Washington, D.C., has a nice collection of witch hazels. You might check the Arboretum’s web site from time to time to see which ones are blooming.
    Stay warm and Happy Gardening!