GROW Magazine from the Pennsylvania Horticulture Society brings a harvest of stories about passionate gardeners, horticultural projects, and great ideas for the home landscape. In the Summer 2018 issue, Denise Cowie asked Mt. Cuba Center horticulturist Susan Boss what her favorite sun-loving perennials are for our region. Her answers are reprinted below, with permission from PHS. To learn more about GROW Magazine visit their website, here.
ASK: Expert Advice for Your Garden
Q: What are the best sun-loving perennials for our region?
Short answer: Native plants such as varieties of Stokes’ aster and penstemon are beautiful and offer benefits for wildlife.
The Details: “Some gardeners think that native plants are too messy or rangy for an orderly garden,” says horticulturist Susan Boss of Mt. Cuba Center, a botanical garden in Hockessin, Delaware. “Actually, if you pick the right native plants for the situation, they can be the best choice. In addition to beating beautiful, they provide vital ecological services, offering nectar for pollinators, and seeds and fruit for birds and other wildlife.
For sunny spots, Boss suggests three elegant and easy-to-grow natives.
Stokesia laevis ‘Peachie’s Pick’, at 12 to 18 inches tall, is shorter than most Stokes’ aster cultivars and also more upright, with flowering stems growing out of basal rosettes of dark-green, lance-shaped leaves. it produces large, bluish-purple flowers beginning in early July and blooms fora longer time than the straight species. Deadheading extends the bloom time; for a large mass planting, Boss recommends simply shearing the tops when the plants have mostly finished flwoering. The cultivar’s compact habit–it is a clumper, not a spreader–makes it ideal for small spaces or containers, and once established it can tolerate some drought.
Penstemon digitalis ‘Husker Red‘, with rosettes of reddish-maroon foliage and white panicles of flowers on 3- to- 4-foot-tall stems, is another clumping plant that can handle dry weather, Boss says. It blooms from May into June, with flowers that “have a pretty, old-fashioned look, and attractive seedheads, too.” She recommends cutting the flowering stalks down tot he rosettes after blooming to allow other alter-blooming plants to fill the space. The cultivar’s maroon foliage combines well with bluish-purple aromatic asters for an attractive fall display, she adds.
In a trial of coreopsis cultivars conducted by Mt. Cuba Center, Coreopsis verticillata ‘Zagreb’, a variety of threadleaf coreopsis, turned out be one of the best. Boss describes the fine-textured foliage as a soft carpet, which is studded with bright-yellow flowers when the plant is in full bloom starting around mid-June. This coreopsis grows about 20 inches tall, spreads by rhizomes, and can fill a large space in a few years. it can be sheared after it finishes flowering to encourage a rebloom. The trimming also allows better air circulation, which will help prevent the powdery mildew that sometimes afflicts the foliage in humid weather. ‘Zagreb’ is the toughest of Boss’s recommendations and can tolerate the driest conditions.