March often brings the end of winter, the beginning of spring, or simply the variability of this seasonal transition. Longer days, increasing sun angles, the equinox, shrinking snowpack, and mud season may define the month. 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 trim garden areas to remove dried vegetation, revealing emerging new shoots. If conditions permit, our professional prescribed fire crew will burn several garden areas, stimulating new growth and renewal.

Several shrubs bloom early in spring, before their leaves have emerged. American hazelnut (Corylus americana) is wind-pollinated, with long catkins (bearing male flowers) that expand and release pollen and tiny purple styles (female flowers). After pollination, the female flowers give rise to hazelnuts enclosed in ruffled leafy coverings later in summer. Both male and female flowers are found on each plant. This shrub grows well in sun or light shade, reaching ten to twelve feet in height.

Serviceberry (Amelanchier spp.) and American plum (Prunus americana), both in the Rose family, have early blooming, fragrant insect-pollinated white flowers. Serviceberries ripen in June. The larger plums ripen later in the summer. Both plants grow well in full or partial sun. The former thrives in a range of well-drained soils in moist or dry conditions, and the latter does well in mesic fertile soils.

Silky dogwood (Cornus amomum) and nannyberry (Viburnum lentago) will reach ten to fifteen 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 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 rabbits live in your garden.

If you have space for a new tree and a moist site with full or partial sun, river birch (Betula nigra) can reach forty to ninety feet tall at maturity. Bark on the trunk is light colored and exfoliates on younger trees and is dark and scaly on older ones. Male and female catkins are present on the same tree, bloom early in the season, and are wind pollinated. This tree has good value for wildlife; for example, the leaves are used by many Lepidoptera species, and birds feed on the mature seeds.

Most of these early blooming species are available from the Friends of the Arboretum online plant sale continuing this month. Trees and shrubs purchased before March 31 will be available for pickup at McKay Nursery in nearby Oregon, Wisconsin, in May.

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 garden curator