Growing penstemons usually requires a valiant effort to mimic wild conditions by creating rock gardens complete with crevices that these beautiful plants’ roots can inch their way into. Most species will suffer without well-aerated, quick draining soil, and can’t live with frequent summer irrigation. Unless you reside where the soil is naturally rocky or gravelly, providing fast drainage in the Pacific Northwest can be a bit challenging. But wait! Penstemon ovatus likes and needs moisture and will usually let you manage with whatever soil you have, providing it drains well and contains a fair amount of organic matter.
Nicknamed ‘broad-leaved’ or ‘egg-leaf’ penstemon, it’s a great asset to a Pacific Northwest garden. Long-lived, upright, and nicely proportioned, it grows from a woody base with glossy, deep green, spade-shaped leaves. When in flower—typically May and June—the plants rise up two to three feet above ground. Speaking of flowers, they are gorgeous: Small (15 – 20 mm) but many, and arranged in whorls on fairly tall inflorescences, they are a brilliant blue that melds into violet and pink.
How it grows
Hardy to Zone 4, this perennial is native to parts of the Northwest (west of the Cascade Mountains) at low to middle elevations, in damp, partly sunny to mostly shady places near forest edges, often in riparian areas. Its natural range is somewhat scattered and includes the western Columbia Gorge and parts of the Willamette Valley, as well as northern areas of the Olympic peninsula and southern British Columbia.
Penstemons, in general, are fantastic pollinator plants that are irresistible to hummingbirds, native bees, syrphid flies, beetles, ants, moths, and others, depending on the species. In my yard I’ve seen P. ovatus attracting syrphid flies, ants, bumble bees, and impossibly small native sweat bees (pictured, right), many of which nest in the ground (so please take care when applying mulch or digging in soil to avoid harming them!). In addition, small songbirds may eat the seeds that mature in summer, and foliage creates cover for tiny soil-dwelling creatures.
Try it at home
Broad-leaved penstemon likes rich soil, regular (but not excessive) watering, and virtually any light situation except very deep shade or full sun, although more sun tends to make the plants flower more. Since it is a fairly robust and versatile plant, placement shouldn’t be too difficult: In my Portland yard I find it does best in some morning sun, a couple of feet in from pathways due to its spread while in bloom. Placing multiple plants in groups or swaths, with each plant 12 to 24 inches apart, will make it easy for pollinators to find them and minimize the amount of bare soil that sprouts weedy plants.
As mentioned earlier, unless your soil is already high in organic matter and drains well, add some low-nitrogen compost before planting (well-decomposed leaf compost is good). I like to get plants in the ground in mid to late fall when forthcoming winter rains will help get their roots established before the demands of spring; if you plant in springtime be sure to keep them adequately hydrated, especially during that first summer. After plants are established (usually a couple of years), they should do fine with just occasional—but deep—watering. If you happen to plant them close to other plants that like frequent irrigation they will likely do fine, but don’t keep them consistently wet. Siting them at the edges of rain gardens should work, but not in the low, saturated parts. They will self sow, but aren’t very assertive.
Another Northwest penstemon for moist conditions and part shade is the beautiful Cascade penstemon (Penstemon serrulatus).
Grab a partner
If possible, grow broad-leaved penstemon with associated species that also naturally occurred in your area, to help provide an eco-functional space for wildlife. Since it naturally occurs within several native plants communities, shrubs and perennials in those communities are far too numerous to list here. For starters, consider serviceberry (Amelanchier alnifolia), red-twig dogwood (Cornus sericea), blue elderberry (Sambucus nigra ssp. caerulea), and Cascade Oregon grape (Mahonia nervosa). As always, buy plants that come from locally sourced material at reputable nurseries.
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