Gardening with Native Plants: Summer Flowers


Lion's-foot (Prenanthes alba)

Technically, February isn’t the end of winter, but it’s the beginning of the end. With small signs, like melting ice and the crunch of soft grainy snow, winter starts to loosen its grip on the landscape this month. Garden tasks include winter pruning, giving presentations, ordering plants, seeds, and tools, and planning for garden work.

In a few months, as spring becomes summer, the number of species blooming in different plant communities changes. Making observations of these patterns in your garden or landscape will show you how to increase diversity, color, and floral resources for pollinators in the garden.

In deciduous woodlands or shady gardens, as the leafy canopy closes in May, spring ephemerals and early blooming woodland species set seed and develop buds underground for the following year. With low sunlight in shady woodlands mid- to late-season, only a few native species bloom. Examples include wild geranium (Geranium maculatum), Virginia waterleaf (Hydrophyllum virginianum), raspberries and blackberries (Rubus spp.), Short’s aster (Symphyotrichum shortii), elm-leaved goldenrod (Solidago ulmifolia), and zig-zag goldenrod (Solidago flexicaulis). All of these are important to insect visitors, for pollinators or as larval hosts.

Bur oak savanna garden in July, with starry campion and Culver's-root blooming.
Bur oak savanna garden in July, with starry campion and Culver’s-root blooming.

Many home landscapes are especially suitable for savanna species, which grow well and bloom in semi-shaded spots under scattered trees or at edges and openings that get only a few hours of sunlight each day. Depending on exposure, buildings on your property might cast appropriate shade as well. A savanna mix will include species for sun and light shade as well as a range of soil types. During late spring and early summer, downy wood mint (Blephilia ciliata) and hairy wood mint (Blephilia hirsuta) flower and self-seed throughout an area. Solomon’s-seal (Polygonatum biflorum) and the Solomon’s-plumes (Maianthemum racemosum and M. stellatum) also flower then. Both also spread by rhizome, resulting in clusters of plants. In mid-season, taller plants like biennial American bellflower (Campanula americana), and perennials pale-leaved sunflower (Helianthus strumosus), giant hyssops (Agastache spp.), and purple Joe-Pye-weed (Eutrochium pupureum) bloom and self-seed. During late summer and early fall, lion’s-foot (Prenanthes alba), arrow-leaved aster (Symphyotrichum sagittifolium), Short’s aster, and woodland goldenrods bloom and self-seed in semi-shaded sites with medium to well-drained soils.

Gardens with partial shade tend to become shadier over time. In that case, you may want to introduce more shade tolerant species in the understory. Growing savanna species can also be a good choice if you lose or have to remove a canopy tree.

The Friends of the Arboretum is now accepting online plant orders through March 15, for pickup in May. Also, plans are well underway for their plant sale under the tent on Saturday, May 14. Planning and ordering now will bring you a diverse flowering garden this summer.

—Susan Carpenter, native plant garden curator