Overview of the Genus
Penstemon, commonly known as Beardtongues are among our most beautiful and varied group of our North American wildflowers. Unique to North America, only one species of over 300 is found outside of our continent, a non descript Asian species. While the genus distributed across the country, these perennial flowers are at their most showy in the western US. Being a western gardener I have come to treasure this varied group enjoying both the giants of the genus like Penstemon palmeri as well as numerous tiny species best used in the rock garden.
>Their Place in Nature and the Garden
In nature Penstemon are usually pioneer plants most commonly growing in and colonizing disturbed soils, road cuts and burned areas. In the garden, Beardtongues prefer plenty of space and don’t like to be crowded. Forget rich, loamy moister retentive soils; “lean” nutrient poor soils with fast drainage are a “must.” And if you can’t mulch with crushed gravel, leave the soil uncovered. Penstemon hate bark, compost or other moisture retentive materials on top of their soil. Penstemon are generally best in young, newly planted gardens with lots of hot sun and open space and rarely persist in older gardens with large shrubs and trees shading the beds and congested conditions as other perennials around them mature.
Getting Them Established
Penstemon are natives best planted as youngsters with lots of vegetative (pre-flowering) vigor. Most of the species in the genus like to get into the soil as soon as possible. I don’t recommend “gallon” sized plants.
Sometimes your best Penstemon plants will be the seedlings of your original transplants. For that reason I don’t recommend “deadheading” transplants. Let them re-seed and you’ll have seedlings more vigorous and long lived than their parent plant.