Penstemon
Penstemons flower from June until the frosts, which among hardy perennials is close to unbeatable, and they ask for almost nothing except sharp drainage and not being cut down in autumn.
They are also short-lived — four or five good years is normal — so the habit worth building is taking a few cuttings every August. They root in three weeks and mean the plant is never actually lost.
Care
Full sun.
Standard border watering.
Free-draining soil of moderate fertility; dislikes waterlogging, especially in winter.
Leave old growth on over winter to protect the crown from frost, then cut back hard to new basal shoots in mid-spring — similar logic to hardy salvia.
A light feed as growth starts and another after the first flush, no more. Penstemons want free-draining, unimproved soil; a rich one gives lush growth that comes through a wet winter far less reliably.
Semi-ripe cuttings in late summer, kept frost-free. Take them every year as routine — penstemons are short-lived and often lost in a cold wet winter, and the rooted cuttings are what replace them.
Month by month
Months change with the climate: in southern Italy tomatoes go out two months earlier than in England.
- AprilCut back hard to new basal shoots once frost risk has mostly passed. how ›
- JuneDeadhead to prolong flowering through summer and autumn. how ›
- NovemberLeave old growth in place over winter for frost protection. how ›
Months based on climate: UK. Your choice stays on this device.
- AprilCut back hard to new basal shoots once frost risk has mostly passed. how ›
- JuneDeadhead to prolong flowering through summer and autumn. how ›
- NovemberLeave old growth in place over winter for frost protection. how ›
Months based on climate: Northern Italy. Your choice stays on this device.
- MarchCut back hard to new basal shoots once frost risk has mostly passed. how ›
- MayDeadhead to prolong flowering through summer and autumn. how ›
- NovemberLeave old growth in place over winter for frost protection. how ›
Months based on climate: Central Italy. Your choice stays on this device.
- MarchCut back hard to new basal shoots once frost risk has mostly passed. how ›
- MayDeadhead to prolong flowering through summer and autumn. how ›
- DecemberLeave old growth in place over winter for frost protection. how ›
Months based on climate: Southern Italy and islands. Your choice stays on this device.
Common problems
How to spot it. Rot at the base.
What to do. Improve drainage.
Popular varieties
Questions
Penstemon: is it hardy?
H4: Hardy through an average UK winter. It survives down to −10 °C.
Can it grow in a pot?
Standard container culture.
Penstemon: when do you prune it?
Leave old growth on over winter to protect the crown from frost, then cut back hard to new basal shoots in mid-spring — similar logic to hardy salvia. In the calendar for UK, pruning falls in April.
Penstemon: when does it flower?
In the climate of UK it flowers in June–October.
When do you feed it?
A light feed as growth starts and another after the first flush, no more. Penstemons want free-draining, unimproved soil; a rich one gives lush growth that comes through a wet winter far less reliably. Feeding months, UK: April, June.