They are considered sensitive and yet easy to care for - the lobelias. If you love them and want to enjoy their splendor for a long time, you shouldn't hesitate to use the secateurs, but put them to use!
When and how should you prune lobelia?
Lobelias should be cut back after the first flowering period from May to July to encourage re-blooming in September and October. Remove spent flowers with clean secateurs or cut the entire plant back to 2/3 of its size.
To extend the flowering period
The flowering period of lobelias usually begins in May. These plants are persistent until July and, depending on the species and variety, present their typical royal blue flowers. Do you want to admire the flowers for longer? Then you should cut the plant!
Removing wilted flowers
Cutting off the withered flowers prevents seeds from forming. At the same time it stimulates the new growth of the lobelia:
- Re-blooming from September and until October
- cut off wilted flowers
- Use hand hedge trimmers or secateurs (€14.00 on Amazon) (clean and sharp)
- alternatively: cut the entire plant back to 2/3 of its size (then 7 to 8 cm tall)
- After the 2nd flowering, pull out/dig up plants and compost them
If you want to harvest seeds, you shouldn't remove all the flowers
If you want to harvest seeds, you should not cut off all the flowers. Leave 3 to 5 inflorescences. They produce fruit sets and seeds. You can harvest these when ripe. But remember: the lobelia takes a lot of energy to form the fruits and seeds, after which its flower production slows down significantly.
Cutting depends on the growth
There are upright, cushion-forming lobelias such as the varieties 'Rosamunde' and 'Kristallpalast'. They are simply cut down. For other varieties that grow hanging (e.g. 'Richardii'), you should also remove the tendrils, which can be up to 80 cm long. There are flowers on them too.
For winterizing perennial lobelias
Most lobelias available on the market die in the fall. The reason is the onset of frost, which these heat-loving plants cannot survive.
But for some species, such as the so-called perennial lobelias, it is worth settling in in winter. You should cut such specimens back to a hand's width above the ground in autumn.
Tip
Prune your lobelias on a dry, cloudy day. Cutting on rainy days increases the risk of disease infestation and cutting in the sun severely weakens the plant.
