Penstemon
An ornamental plant, planted March to October, or sown March to May.
In September: cut back the penstemon. It can be planted now.
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Penstemon, month by month
Bar: the usual months. Sprout: this month.
| Sowing, planting or job | Sep | Oct | Nov | Dec | 2027Jan | Feb | Mar | Apr | May | Jun | Jul | Aug |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sow under cover. | none | none | none | none | none | none | usual | usual | usual | none | none | none |
| Plant a pot-grown penstemon. | usual | usual | none | none | none | none | usual | usual | usual | usual | usual | usual |
| Cut back the penstemon. | usual | usual | usual | none | none | none | usual | usual | usual | none | none | none |
| Mulch the penstemon. | none | none | none | none | none | none | usual | usual | usual | none | none | none |
| Stake the penstemon. | none | none | none | none | none | none | usual | usual | usual | none | none | none |
| Deadhead the penstemon. | none | none | none | none | none | none | none | none | none | none | none | usual |
What to do, and when
The usual months for a UK garden. Your own plan gives the week.
Sowing and planting
Sow under cover March to May, 5mm deep. Strong sources: RHS and Mr Fothergill’s.
Plant a pot-grown penstemon March to October, 45cm apart. Strong source: RHS.
Cut back the penstemon
In autumn cut back by about a third; in spring cut to just above the lowest new shoots.
Usually March to May, and September to November. Strong source: RHS.
Mulch the penstemon
Use well-rotted manure or garden compost; in borders that is usually all the feeding they need.
Usually March to May. Strong source: RHS.
Stake the penstemon
Use pea-sticks as support.
Usually March to May. Moderate source: RHS.
Deadhead the penstemon
Usually August. Moderate source: RHS.
What the source words mean
Strong: the RHS page for this plant is among them.Moderate: another trusted UK source, or the RHS on its group.
Every line above names the page it comes from. Where we found no good source for a job, we left it out. Where the name “Penstemon” comes from.