Outdoors
Penstemon
Penstemon
Spires of magenta foxglove-shaped bells over narrow grey-green leaves, flowering from June until the frosts if you keep deadheading.
- In flower now
- Perennial
- Average
- Type
- Perennial
- Light
- Full sun
- Water
- Average
- Hardiness
- H5
- Where
- Border
- Flowers
- June–October
- Colour
- magenta, pink
Flowering year
Flowers June–October. It is currently August, so this plant is in flower.
Will carry on into November in a mild autumn, on progressively shorter side spikes.
Outlined month is August, today.
Position and soil
- Sun
- Full sun
- Partial shade
- Aspect
- East-facing
- South-facing
- West-facing
- Exposure
- Exposed
- Sheltered
- Soil
- Chalk
- Loam
- Sand
- Moisture
- Well-drained
- Soil pH
- Acid
- Alkaline
- Neutral
- Ultimate size
- 0.5-1 metres tall × 0.1-0.5 metres wide · 2-5 years to get there
- Habit
- Clump forming
- Foliage
- Semi evergreen
- Family
- Plantaginaceae
Sourced from the RHS. Figures are for the common border cultivar Penstemon 'Andenken an Friedrich Hahn'; our magenta hybrid is unidentified. The H5 hardiness rating is that cultivar's as well, and penstemon hardiness varies a good deal between cultivars.
Care
- Watering
- Water it while it is settling in and during a real drought, but otherwise leave it alone. Cold wet soil in winter is far more dangerous to it than dry soil in August.
- Feeding
- A spring mulch or a light balanced feed is plenty. Rich feeding gives you soft floppy growth and fewer flowers.
- Pruning
- Deadhead spent spikes as they go over and it keeps producing side shoots. Leave the old stems standing through winter, then cut back in spring.
Winter — Nothing to do
Do nothing in autumn. The old woody stems are what shelters the crown through frost, so leave them standing however untidy they look. Cut back in April or so, once low new shoots are clearly showing at the base, and take the old growth down to just above them. Tidying a penstemon in October is the single most common way of killing one.
Narrow willow-like leaves in a loose bushy clump, with upright stems carrying rows of tubular magenta bells, each one flared and white-throated at the mouth. Bumblebees disappear inside them entirely.
What it actually wants
Free-draining soil and full sun, and that is most of it. Penstemons do not really die of cold in this country — they die of sitting in wet ground through a mild grey winter, which is a different thing and much more common. Heavy, slow soil is the problem to solve, not the temperature.
The other thing worth knowing early: this is a short-lived plant. After four or five years it goes woody at the base, flowers less and eventually gives up, regardless of how well you have treated it. The answer is not better care but cuttings. Non-flowering side shoots taken in late summer root easily in gritty compost and are in flower the following year, so there is always a replacement coming. Taking a few every August costs nothing and removes the whole problem.
Deadheading genuinely works here. Cut a finished spike back to a leaf joint and it throws side shoots that flower again, which is what stretches the season from July to the first frosts.
Winter
Leave it entirely alone. The dead stems standing over the crown are doing a real job, and this is a plant people kill with tidiness rather than neglect. Wait until spring, find the new shoots low down, and cut everything above them away then.