Its assignment to the winter hardiness zone Z6b with a frost tolerance down to -20.4 degrees Celsius lulls us into security. However, a butterfly bush is not immune to frost damage. A Buddleja davidii or its magnificent varieties do not necessarily have to be frozen to death. You can find out here how a vitality test works and which measures make sense now.
How do I recognize frost damage to the butterfly lilac and how do I save it?
A chipped butterfly lilac shows brown-colored bark. Carefully remove bark from branch locations; Green tissue underneath means he althy wood, brown tissue means frostbitten wood. Cut frozen shoots back to 30-50 cm and then fertilize generously.
Frozen or not? – This is how the vitality test works
If a butterfly bush has established itself well in the bed, even bitter frost will not cause any problems. Threatening frost damage usually occurs when the grim frost strikes again mercilessly in late winter after a period of mild weather. The ornamental shrub cannot cope with this strenuous back and forth and freezes back drastically. With a vitality test you can find out whether there is still life in your Buddleja davidii. This is how it works:
- Pick up a sharp, disinfected knife
- Scrape off some of the browned bark on the branch
- Remove only a little of the bark to reveal the tissue underneath
If green tissue appears under the bark, life is still pulsating in the shoot. Wherever there is brown tissue beneath the surface, the branch is frozen.
Pruning brings the butterfly bush back on track
If the vitality test has shown that a butterfly bush is only partially frozen, there is legitimate hope for a summer bloom. Now you can benefit from the fact that this type of buddleia always blooms on this year's wood. Therefore, cut all shoots back to 30 or 50 cm. Completely dead shoots are thinned out at the base.
Care after pruning
The harsh winter and consistent pruning have taken a lot out of your butterfly bush. So that it now has enough energy reserves for fresh growth, it receives a generous portion of compost with horn shavings. Rake the fertilizer material only superficially onto the root disc and water again. Pamper a shrub in a pot with liquid fertilizer for flowering trees.
Tip
A butterfly lilac in a pot is at risk of frost damage even at an advanced age. In contrast to its counterparts in the bed, it cannot achieve winter hardiness down to -20 degrees Celsius. Ideally, the shrub overwinters in a frost-free room.
