January is usually a month of deep winter in our gardens and landscapes. But this year, what will follow an unseasonably warm and snowless end of December? Garden tasks, as outdoor conditions permit, include pruning as well as assessing and clearing up storm damage. Indoors, garden plans and early plant orders are well underway.
Friends of the Arboretum offers an advance order native plant sale. This is a great opportunity to get native trees, shrubs, groundcovers, garden mixes, and full and half flats of popular species. Orders are accepted through February 14 and pickup is May 7—just in time for spring planting.
Several of the native trees and shrubs available for sale have distinctive winter features, which you can observe in our collections this season. River birch (Betula nigra) has red-brown bark, which peels along the trunk, revealing lighter colors. The canopy branches are open and arching. It is a relatively fast growing tree that does well in moist soils, or on the shaded side of a building, or low on a north slope. Also in the birch family, musclewood (Carpinus caroliniana) has sculptured yet smooth gray bark and a spreading form. The female catkins bearing seeds (winged nutlets) persist after autumn leaf drop. This tree grows more slowly than river birch but thrives in similar moist shady habitats. It can also grow in sunny dry sites, preferably with rich soils. Witch hazel (Hamamelis virginiana) blooms in October, and its golden fall leaves may persist into the winter. It has a rounded form at maturity, and grows well in moist soils. Winterberry (Ilex verticillata) is a deciduous holly which produces bright red berries along the stems of the female plants. Plant at least one male plant as a pollen source for nearby female plants to produce berries. These berries are a late season food source for birds and small animals.
Other trees and shrubs, such as silky dogwood (Cornus amomum), swamp white oak (Quercus bicolor), and hazelnut (Corylus americana) produce nuts or fruits used by wildlife in late summer and early fall. Apple serviceberry (Amelanchier x grandiflora) and dwarf bush honeysuckle (Diervilla lonicera) support pollinators in spring and early summer, respectively.
This year four groundcover species are available during the advance order sale. Prairie smoke (Geum triflorum) covers the ground with clusters of leafy rosettes, which send up short stalks of red-pink flowers in early spring. These are followed by wispy pink and gray heads (the “smoke”) when the fruits are mature. The other three groundcovers spread effectively by stem, rhizome, and runners. Wild ginger (Asarum canadensis) grows best in wooded or semi-shaded areas. Its inconspicuous flowers open early in spring. The seeds can be transported to other garden spots by ants, but the plant mainly spreads by rhizome. Pennsylvania sedge (Carex pensylvanica) and wild strawberry (Fragaria virginiana) grow well in sun or semi-shade. Penn sedge is one of, if not the earliest, plant to bloom in the native plant garden, and wild strawberry blooms in May. Its small fruits develop in June. Both of these species can be used in rock gardens as well.
Next month I will share information about native plant garden mixes and single species full and half flats available through the FOA advance order sale. If you would like to order a species that is not listed for sale, please email the Native Plant Sale coordinator for availability and pricing—we may be able to order your special request.
—Susan Carpenter, native plant gardener