When to plant and prune Verbena bonariensis (purple top)
Verbena bonariensis (purple top) flowers from mid June to mid October and the dates below cover planting, flowering and the pruning window.
Planting, flowering and pruning by region
Verbena bonariensis (purple top) is grown to the calendar rather than to the frost, so the same dates apply across the whole UK and every region below reads the same. Where a plant’s timings do follow the frost, Plot shifts them from the Midlands and Lowland Wales baseline using Met Office average frost dates.
| Where you are | Plant | In flower | Prune |
|---|---|---|---|
| South West Coast and Cornwall | late March to mid May | mid June to mid October | late February to late March |
| South Coast and Channel | late March to mid May | mid June to mid October | late February to late March |
| Greater London (Urban Heat Island) | late March to mid May | mid June to mid October | late February to late March |
| South East and Home Counties | late March to mid May | mid June to mid October | late February to late March |
| East Anglia | late March to mid May | mid June to mid October | late February to late March |
| Midlands and Lowland Wales | late March to mid May | mid June to mid October | late February to late March |
| Wales and West Coast | late March to mid May | mid June to mid October | late February to late March |
| Northern England | late March to mid May | mid June to mid October | late February to late March |
| Scotland Lowlands and Central Belt | late March to mid May | mid June to mid October | late February to late March |
| Scotland Highlands and Islands | late March to mid May | mid June to mid October | late February to late March |
| Northern Ireland | late March to mid May | mid June to mid October | late February to late March |
| Channel Islands and Isle of Man | late March to mid May | mid June to mid October | late February to late March |
Growing notes
Self-seeds prolifically, and those seedlings are how it keeps going after a hard winter, so hoe out the ones you do not want rather than trying to stop it seeding. The tall, wiry stems snap in exposed sites but stay see-through in a border, so it can be planted near the front.
At a glance
- Spacing
- 45 cm between plants
- Eventual height
- 180 cm
- Eventual spread
- 45 cm
- Hardiness
- H4
- Sun
- Full
- Frost tender
- No
- Grows in a container
- Yes, 15 litres or more
- Balcony rating
- 4 out of 5
Feeding
No routine feeding needed; it flowers best on lean, well-drained soil.
Pruning: what to avoid
Do not cut it back in autumn: the standing seedheads feed birds, allow the self-seeding that replaces winter losses, and give the crown some protection.
Pruning group
Cut the old stems down before new growth starts in spring, to encourage several stems from the base.
Winter protection
In colder gardens spread a dry mulch of straw or similar thickly over the root zone in autumn; move containers into a greenhouse or porch.
What usually goes wrong
- losses in cold, wet winters
- wind snapping the stems
- unwanted seedlings
Related guides
Timings cross-checked against RHS guidance for verbena bonariensis (purple top).