Zone: 3 to 8
Soil: Sand to loam
Light: Full sun to part sun
Bloom colour: White, pink and red
Bloom period: June to July
Height: 24 to 36 inches
Moisture: Dry to medium
Attracts: Bumblebees and hummingbirds
Notes: There are hundreds of Penstemons found in North America, but only three species are native to Ontario. The two most commonly available species are Penstemon digitalis and Penstemon hirsutus.
The deep corolla of these plants makes them suited to pollination by long-tongued bees and hummingbirds. Penstemons may sometimes be referred to as beardtongue due to an infertile stamen that protrudes from the flower and which can be hairy. In Penstemon hirsutus, the function of the staminode is to make a bee brush the stigma and deposit pollen from another plant before collecting any new pollen. This encourages cross-fertilisation. You may notice that Penstemon digitalis does not have a "beard". Its staminode is shorter and terminates inside the flower.
Penstemon hirsutus, blooming in late spring, is one of the earlier flowering perennials that provides much needed food for queen bees. Most of the leaves are basal and it grows less than 2 feet high. While Penstemon digitalis seems to be more available in nurseries, Penstemon hirsutus with it dense cluster of flowers is a worthy addition to a flower garden. This plant really needs full sun and dry well drained soil. In part sun, it is unlikely to thrive and will stop flowering.
Penstemon digitalis is a lot more versatile and will grow in a variety of conditions except full shade. It is an easy plant to grow in a garden. It is taller than Penstemon hirsutus and the flowers are borne further apart. It flowers in early summer and combines well with downy woodmint and yellow coneflower as their blooming times overlap. A decent sized patch of this Penstemon will definitely attract the attention of hummingbirds.
There are many more Penstemon species out west, which are important plants for hummingbirds that migrate at elevation through the mountain chains. One common import from there is Penstemon barbatus. If you compare it to the other species shown, you will notice that its corolla is deeper and narrower, which discourages bees. Its flowers are more specialised for pollination by hummingbirds.
Species in Ontario include: