Penstemon Care
Penstemons are tough perennials that can stand up to some pretty intense growing conditions. This tiny alpine species, native to North America, can grow in the cracks of rocks and stand up to extremely cold weather, while others grow in disturbed soils in prairie settings. No matter where they’re growing, penstemons need extremely well-drained soils and will not tolerate wet soils, especially over the winter. The prairie-type penstemons are much more tolerant of standard garden soils, whereas the alpine varieties require very sharp drainage, similar to what is found in gravel gardens and even trough gardens. No matter what type of penstemon you plant, all perform well in fairly nutrient-poor soils and will tend to put out too much tender growth in rich soils. Penstemons also need full sunlight to perform their best. Not only will this ensure that they put out quality blooms, but it will also prevent them from flopping and reduced the risk of the plant developing powdery mildew on the leaves, especially in humid summers. After the plants have bloomed, penstemons will produce copious amounts of seed. If you are hoping to have your penstemon plants freely seed around your garden, make sure to leave a few stalks on the plants so they can fully ripen and disperse. Otherwise, you can remove spent blooms to encourage a second wave of flowers. In some types, the seedpods can also be ornamental and can be left on the plants for winter interest.
Colorful Combinations
With a rainbow of colors to choose from, everyone can find a penstemon varietal to love. The beautiful spires of tubular blossoms add loads of color to the garden and are beloved by hummingbirds and butterflies alike. With such a wide variety of species and cultivars to choose from, you can have penstemon blooming for almost the entire growing season. The blooms look stunning in a garden setting and make a wonderful addition to a cut flower arrangement. Along with their bright blooms, many varieties of penstemon also have colorful foliage to add to the mix. Varieties like ‘Husker Red’ have burgundy foliage and add another level of interest to these already spectacular garden plants. Other varieties have glossy green or blue-gray foliage that looks good all season long.
New Innovations
With hundreds of species available, there are constantly new penstemon varieties being produced. In many cases, new varieties tend to be improvements of older types, with larger blooms, more compact habits, or darker foliage. There is also work to create continuous-blooming annuals. There are already several on the market that boast extremely long blooming times and a few that will bloom nonstop from spring until frost.
More Varieties of Penstemon
Common penstemon
Penstemon barbatus blooms with narrow spikes of two-lipped tubular flowers about 2 inches long in spring. The colors can be red, pink, carmine, or purple, and the 8-inch lance-shape leaves have a whitish bloom. The plant can reach 3-6 feet tall. USDA zones 4-9
‘Dark Towers’ penstemon
An even darker variety of the much loved ‘Husker Red’ varietal, ‘Dark Towers’ holds onto its to the burgundy foliage throughout the summer, and its blooms have more of a pink flush as well. USDA zones 3-8
Penstemon hirsutus Pygmaeus
Lavender blooms with white lips nod above dense green leaves on this dwarf plant that reaches up to 6 inches tall. USDA zones 3-9
‘Electric Blue’ penstemon
Penstemon heterophyllus ‘Electric Blue’, just as its name implies, has flowers that glow with color. Notably drought-tolerant, this plant can grow to be up to 18 inches tall. USDA zones 6-9
‘Husker Red’ penstemon
Penstemon digitalis ‘Husker Red’ blooms in early to midsummer with loose spires of 1-inch tubular pink-flushed white flowers. The lance-shape leaves are deep maroon in color, 4-5 inches long, and arranged in a basal rosette. It grows about 2-1/2 feet tall. USDA zones 3-8
Pine-leaf penstemon
Penstemon pinifolius is a summer bloomer with loose spires of 1-inch narrow scarlet tubular flowers. It has needlelike foliage and is slightly woody at the base, making the species an excellent choice for dry rock gardens or walls. USDA zones 4-10
Penstemon Companion Plants
Lady’s Mantle
Lady’s mantle looks great in the garden and in a vase. Its scalloped leaves catch rain or dewdrops, making them look dusted with jewels, while the chartreuse flowers appear in playful, frothy clusters above the foliage. Lady’s mantle is ideal for softening the edge of a shaded path or creating a groundcover in dappled shade.
Lamb’s Ear
Lamb’s-ears is a top pick for a groundcover in a hot, baked spot. Its silver felted foliage quickly forms a dense, delightful mat while contrasting nicely with other foliage and flowers nearby. Depending on the type varietal you choose and your growing conditions, your lamb’s ear may self-sow freely to the point of becoming a bother. In hot, humid climates, lamb’s-ears may “melt down” in summer, becoming brown and limp.
Catmint
Catmint is one of the toughest perennials you can grow. It’s a proven performer during hot, dry weather, and the silvery foliage and blue flowers look great most of the season. Deadhead or cut back hard after the first flush of bloom to encourage more flowers. Average, well-drained soil is usually sufficient. Tall types may need gentle staking; it sometimes seeds freely.
