Tall floral scapes tipped with small bell-shaped flowers, so close to foxglove that the two are constantly confused: this is penstemon, or beardtongue, a perennial from the vast American plains grown for colour from late spring right through to mid-autumn. Give it full sun and rather rich, well-drained soil, and the display lasts all summer.
Penstemon at a glance
Name
Penstemon
Family
Scrophulariaceae (figwort family)
Type
perennial
Height
26 to 32 inches (0.6 to 0.8 meters)
Exposure
full sun, part sun
Soil
rather rich and well drained
Flowering
late spring to mid-autumn
Easy to grow, here are the best practices to care for your Penstemon and extend their blooming.
If you purchased your plants in nursery pots, it is best to plant them in the ground in spring, spacing them 12 inches (30 cm) apart and adding “flower plant” soil mix to the garden soil.
Plant at least ten plants in any given bed to produce a remarkable visual impact.
Water regularly after planting.
Planting Penstemon in pots
Penstemon thrive particularly in pots or garden boxes.
Plant in flower plant soil mix.
Water regularly at the beginning and then, especially in summer, only when the substrate surface is dry.
Never flood the roots.
Sowing Penstemon
Sowing Penstemon is difficult and efforts aren’t always crowned with success.
Sow in a sheltered place, in a nursery at the end of winter in special seedling soil mix.
Place seedlings to light at a warm temperature, around 65 to 68°F (18 to 20°C).
Sprinkle water over lightly to keep the substrate a bit moist.
Transplant into nursery pots after sprouting when sprouts have formed a few leaves.
Transplant in the ground in the following spring.
Preparing Penstemon cuttings
To propagate your Penstemon easily, summer cuttings are definitely the best solution. You can even use stems pruned off in spring to prepare cuttings.
Snip off cuttings from Penstemon stems that aren’t bearing flowers.
Eventually, dip the cuttings in powdered rooting agents (this step isn’t necessary, but it helps).
Keep substrate a little moist, reduce watering in winter.
Protect cuttings from freezing in winter but keep them in a well-lit place.
Transplant in the ground in the following spring.
Strip the lower leaves so no foliage sits buried in the compost and rots.
Penstemon clumps are short-lived and can be lost outright to a hard winter so root a few spare cuttings as replacements.
Pruning and caring for Penstemon
Pruning and caring for Penstemon is easy. Apart from the occasional watering during summer, you won’t need to care for them at all.
To boost flower-bearing, remove wilted flowers regularly (deadheading), since this will stimulate the budding of new blossoms.
Water Penstemon in case of high temperatures, preferably in the evening.
Mulching the base of your Penstemon helps keep the soil cool and reduces the need to water.
In winter, no need to remove leaves: they protect Penstemon from the cold. What is best is to cover the plant with a thick layer of dead leaves to keep it from freezing.
Penstemon are hardy to temperatures as low as 23°F (-5°C) and even 5°F (-10°C), depending on the variety.
All there is to know about Penstemon
Bell-shaped flowers on tall scapes, easily mistaken for foxglove
Native to the vast American plains, Penstemon is a very beautiful perennial that bears large floral scapes with cute bell-shaped flowers at their tip. Often compared to foxglove, they are often mistaken one for the other.
Also called beardtongue, there are over 250 varieties of Penstemon with as many colors, shapes and sizes.
Dominant Penstemon colors are red, violet and yellow.
Choosing a penstemon by colour
With over 250 varieties of penstemon, colour is what most gardeners choose on. Here are the ones named in this article, side by side.
Choosing a penstemon by colour
Variety
Flower colour
Type
Penstemon barbatus
Cherry red
Species
‘Evelyn’
Pale pink
Cultivar
‘Garnet’
Raspberry red
Cultivar
Penstemon heterophyllus
Lavender blue
Species
‘Hidcote Pink’
Pink
Cultivar
‘Midnight’
Purple
Cultivar
‘Souvenir d’Adrien Régnier’
Pink
Cultivar
‘Snow storm’
White
Cultivar
‘White Bedder’
White
Cultivar
Red, violet and yellow dominate the genus, but the white and pink cultivars are just as easy to grow.
Smart tip about Penstemon
You can also cut a couple Penstemon flower stems and place them in a vase, they keep for a long time!
Image credits (edits Gaspard Lorthiois):
CC BY 2.0: tdlucas5000
Written by Gaspard Lorthiois | Loves helping out, especially when it comes to growing things. Worked in herbal medicine, runs a farm, and dabbles in tech. Master's degree and engineer.