In general, the buddleia is considered to be very frost-tolerant and is hardy down to around minus 20 °C. However, this does not apply to all species and varieties, but only to Buddleja davidii, also known as butterfly lilac. However, rarer species such as the ball buddleia (Buddleja globosa) are not hardy. But the robust Buddleja davidii can also freeze back in severe frost - although it usually sprouts again.
How do I know if my buddleia is frozen?
To determine whether a buddleia has frozen, do the thumbnail test: carefully scratch the bark of several shoots. If the bush is still alive, a green layer appears under the bark. Cut back frozen shoots and encourage growth with horn shavings and compost.
How to tell if the buddleia is frozen
Frosty winters usually don't affect planted buddleia. It only becomes problematic in late winter / early spring, when the weather and light levels signal the plant's “beginning of spring” and it gradually awakens from hibernation. A frosty night at this time can have fatal consequences, and not just for buddleia. Therefore, in the event of late frosts, you should always cover it with a protective fleece, which you remove again during the day. However, if the bush is frozen, you can use the thumbnail test to determine whether there is still life in it. To do this, carefully scratch the bark on several shoots with your thumbnail so that the underlying layer becomes visible. If this is green, the bush is still alive and can be started again.
Rescue measures for frozen buddleia
You should “put frozen buddleia on the stick,” as the gardener says. To do this, shorten all shoots to around 20 to 30 centimeters so that the shrub puts its energy into new growth. You can support it by carefully working a generous handful of horn shavings (€52.00 on Amazon) and a generous scoop of compost into the soil in the area of the root disk. Afterwards, the only thing that helps is to wait - but since buddleia is very robust, it will most likely sprout again.
Young buddleias are more sensitive
However, you should be particularly careful with young buddleias: These are much more sensitive than older, well-rooted and therefore established specimens and therefore freeze back more quickly. Light winter protection during the winter months can prevent freezing. The same applies to buddleias grown in pots, which do not have the same winter hardiness as their planted relatives. Proper winter protection or even frost-free wintering in a cool, bright room can be useful here.
Tip
Due to its sheer size, not all varieties of buddleia are suitable for pot cultivation. Only the small variants should be cultivated here.
