Spring has arrived in the Arboretum native plant garden, with spring ephemerals blooming, bluebirds and tree swallows exploring nest boxes, and tree and shrub buds opening. However, we are not on-site—the Visitor Center is closed and gardening activities are postponed at the Arboretum. Our home gardens are places of refuge and can illustrate spring changes over the past few weeks. Several garden volunteers have shared exciting observations of spring’s arrival in their own gardens as well as their new landscape projects.
Garden tasks this month include trimming last year’s growth, removing early weeds, identifying seedlings, and recognizing perennial shoots as they emerge and develop. I’ve done some gardening at home this season (for a change) and observed a contrast between my shade and sun gardens that I hadn’t noticed before. The native plants in my shaded beds are growing densely, with little bare soil between them. Many of them are clonal species—for example, wild ginger (Asarum canadense), mayapple (Podophyllum peltatum), and toothwort (Cardamine concatenata). Plants that do not spread by rhizome (underground stems that grow horizontally) include ferns that form a thicker crown each year and hold space in that way. Others, like Virginia bluebells (Mertensia virginica), spread by seed and are scattered among the other plants. Some species are colonizing the adjacent lawn—wild ginger and bluebell seedlings have established there by seed.
In my prairie garden with mesic soil, the plants are growing less densely and more bare soil is visible. This garden has more variation in height among the species and more shading of the smaller species. Wild roses (Rosa spp.), New England aster (Symphyotrichum novae-angliae) and cup-plant (Silphium perfoliatum) are the tallest plants. Smaller plants include butterfly-weed (Asclepias tuberosa), little bluestem (Schizochyrium scoparium), Rudbeckia species like black- and brown-eyed Susans, Echinacea species like purple coneflowers, prairie-smoke (Geum triflorum), and others. On its own, this garden has expanded gradually from its original size, and butterfly-weed is seeding yards away in the adjacent lawn. I am interplanting additional prairie species into the open spaces in this garden and discouraging cup-plant by cutting stalks and digging out smaller shoots. (This patch of cup-plant began with one tiny seedling planted about twenty-five years ago—I do not recommend it for a small or medium garden space.)
These spring weeks are a time of surprising change in gardens. Cued by warmer air and soil temperatures, more sunlight, and rainfall, growth is noticeable day to day. Small tight leafy rosettes of wild columbine (Aquilegia canadense) have fully expanded and begun to produce flowering stalks that bloom in May. In just three weeks, wild ginger leaves have unfolded and expanded, forming a full ground cover, and its flowers are blooming under its wide leaves.
While you garden, watch for birds in migration, insect emergence, and animal activity. In my garden, yellow-rumped warblers (Setophaga coronata) appeared last week (still migrating north). This is a common bird that is seen only for a brief time in our area, as they do not winter or nest here. Early spring bees are out visiting early blooming woodland wildflowers, willow, and ornamental flowering shrubs and trees (e.g., Prunus spp.). Some queen bumble bees have emerged in our area—two-spotted (Bombus bimaculatus), common eastern (B. impatiens) and rusty-patched (B. affinis). They are visiting spring ephemerals such as Dutchman’s breeches (Dicentra cucullaria) as well as weeds like creeping Charlie (Glechoma hederacea). Look for milkweed shoots emerging. When they are a few inches tall, you may see monarchs from the first generation that hatched in the southern U.S. arriving to lay eggs on your milkweed. You can document your observations on citizen science portals like eBird, Bumble Bee Brigade, and Journey North. Please share your garden questions and observations with us and enjoy May.
—Susan Carpenter, native plant gardener