Earlier this month, somewhere in the dry woods and rocky hillsides of Penobscot County, the rare hairy beardtongue (Penstemon hirsutus) was blooming. At the same time and nearly statewide (excepting Piscataquis and Washington Counties), the uncommon foxglove penstemon (P. digitalis) was flowering in fields and woodland borders. Although I’ve done my share of botanizing where these herbaceous perennials grow, I’ve missed them, perhaps spending too much time looking up into the canopies of trees instead of down on the ground.
I know penstemons from gardens, including the University of Maine Cooperative Extension native plant garden in Ellsworth, where both species thrive in full sun. A cultivar of the foxglove penstemon with maroon-colored leaves, Husker Red, also grows in Marjorie’s garden to the delight of ruby-throated hummingbirds.
The genus name Penstemon, from the Greek, means “five stamens”. Four of the five are fertile, the fifth sterile with a tuft of small hairs. It is this hairy sterile stamen that gives the plants their common name, beardtongue.
The hairy beardtongue is a woolly-stemmed plant growing 16 to 24 inches tall with open, stalked clusters of lavender, trumpet-shaped flowers, each about 1 inch long with a white tip. The foxglove penstemon is taller, growing from 3 to 5 feet in height with a spread of 2 feet.
Its flowers are white, slightly longer than those of hairy beardtongue, and are borne in panicles atop erect, rigid stems. Both species have a clump-forming growth habit.
Best in full sun, penstemons will tolerate partial shade. They need well-drained soils and can tolerate periods of moderate drought.
More common in garden centers than in the wild, our native penstemons are ideal candidates for the pollinator garden. Both attract hummingbirds as well as bumblebees and butterflies. The hairy penstemon is a documented host for the Baltimore checkerspot butterfly, a species found in southern and central Maine.
Beneficial insects, including ladybugs and parasitic wasps,whose larvae feed on aphids and other garden herbivores, require a source of pollen and nectar as adults. Native penstemons provide these essential foods.
Blooming with the penstemons and continuing through August is a pollinator-attracting native shrub with the common name of meadowsweet (Spiraea alba var. latifolia). From late July through August, the soft pink of meadowsweet’s small flowers, borne in terminal branched clusters, is a pleasing contrast to the bolder bright yellows of our native goldenrods.
The beauty of meadowsweet extends beyond its summer flowers. In autumn, the leaves turn to tarnished gold and in winter the pale brown to red-brown seed heads float shadows on the garden’s blanket of snow.
In a comprehensive study of native plants conducted by Michigan State University, meadowsweet was the third-most-attractive plant to beneficial predator insects and spiders, more than four times as effective in attracting predators as a grass control. Beneficials attracted by meadowsweet included both crab and jumping spiders; soldier beetles that eat aphids and other insects; plant bugs that prey on leaf beetles; damsel bugs that prey on aphids, leafhoppers, mites and caterpillars; lady beetles important in controlling aphid populations; and ichneumonid wasps, parasitic wasps that prey on beetles and caterpillars.
In the same study, meadowsweet attracted moderate numbers of bees, including bumblebees, sweat bees and Andrenid bees, very common spring pollinators in Maine.
Imagine the diversity of life in a mixed garden border that grows native penstemon, goldenrods and meadowsweet, as well as other native plants. Imagine the abundance of pollinators for summer vegetables growing nearby.
Growing these native plant species together in the garden represents the essence of bringing nature home.
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