- Frozen or not? - This is how the vitality test works
- Pruning brings the butterfly bush back on track
Its assignment to winter hardiness zone Z6b with a frost tolerance of up to - 20.4 degrees Celsius gives us peace of mind. Nevertheless, a butterfly bush is not immune to frost damage. A Buddleja davidii or one of its magnificent varieties does not have to be hopelessly frozen. Here you can find out how a vitality test works and which measures are now sensible.
Well-rooted Buddleia do not mind snow and frost
Frozen or not? - This is how the vitality test works
If a butterfly bush has firmly rooted itself in the bed, even the icy bits will not cause any problems. Dangerous frost damage usually occurs when, after a mild weather period in late winter, frost strikes again mercilessly. The ornamental shrub cannot cope with this strenuous back and forth and freezes back drastically. With a vitality test, you can determine whether life is still stirring in your Buddleja davidii. That is how it goes:
- Take a sharp, sanitized knife
- Scrape off a little of the brown discolored bark on the branch
- Only remove a small amount of bark to reveal the underlying tissue
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 flowering period. Now you can benefit from the fact that this summer lilac species always blooms on this year's wood. Therefore, cut back all shoots to 30 or 50 cm. Completely dead shoots are trimmed at the base.
Post-pruning care
The hard winter and consistent pruning have demanded a lot from your butterfly bush. So that it now has enough energy reserves for a fresh shoot, it receives a generous portion of compost with horn shavings. Spoil a shrub in a bucket with liquid fertilizer for flowering shrubs.
tips
A butterfly bush in a tub is also at risk of frost damage at an advanced age. In contrast to its conspecifics in the bed, it cannot develop a winter hardiness down to - 20 degrees Celsius. Ideally, the shrub overwinters in a frost-free room.