Despite the possibility of snow or ice storms this month, gardeners anticipate March. We note longer days, increasing sun angles, the equinox, shrinking snowpack, and the early stages of mud season. Garden tasks include dormant pruning, clearing storm damage, and looking for small signs of spring. At the end of the month, weather and soil conditions permitting, we may trim garden areas to remove dried vegetation over emerging new shoots. If conditions permit, our highly trained prescribed fire crew will burn several garden areas, stimulating new growth. Be sure to complete oak pruning before the end of March.
If you have space and full sun (six or more hours of sun) consider planting a swamp white oak (Quercus bicolor). The name refers to the leaves, which are pale on the underside with shallow rounded lobes. This species is found in southern Wisconsin, and has a moderate growth rate, reaching a mature size of 50 to 60 feet tall and wide. It thrives in moist and wet soils, but can survive on upland sites, too. It is a good idea to plant a small tree, as it will recover from transplanting sooner than a larger specimen will. Herbaceous savanna species will grow well in its shade.
If space is more limited, the shrubs silky dogwood (Cornus amomum) and nannyberry (Viburnum lentago) will reach 10 to 15 feet in height at maturity. They both produce clusters of white flowers in early summer followed by berries that turn dark blue or black before the leaves turn to deep red, maroon or burgundy in fall. Both grow well in full or partial sun (four to six hours of sun). Silky dogwood grows well in moist soils and nannyberry can thrive in dry or moist well-drained soils.
Two smaller shrubs, black chokeberry (Aronia melanocarpa) and dwarf bush honeysuckle (Diervilla lonicera) grow well in moist and dry soils, respectively. Chokeberry has glossy leaves, clusters of white flowers, black fruits, and red fall color. Dwarf bush honeysuckle (not to be confused with invasive honeysuckle) has yellow flowers, inconspicuous fruit, and multiple arching stems. Both grow in full sun or partial shade. I recommend caging the chokeberry if your garden has rabbits.
The woody species described above (and others) are available from the Friends of the Arboretum 2021 plant sale. Orders are due by March 15, with curbside pickup for woody species at Winterland Nursery in nearby Oregon, Wisconsin, in May. Order trees and shrubs online at the Friends of the Arboretum e-store.
Planting a small tree or shrub now will create wildlife habitat, shade, color, and beauty in your garden for years to come.
—Susan Carpenter, native plant gardener