Rapidly growing, the butterfly bush forms a superb shrub, reaching 2 to 6 m in height and almost as wide. In addition to promoting flowering, pruning gives it a harmonious and compact shape.
When to prune the butterfly tree?
The butterfly bush (
Buddleja davidii
) is pruned at the
end of winter, in February or March,
before the buds swell and vegetation resumes. At this time, the big winter frosts are normally over. Pruning too late harms its flowering, while pruning too early, in October for example, affects its resistance to frost.
The butterfly tree flowers
on the wood of the year:
severe pruning stimulates its flowering, and allows you to obtain an elegant and very compact shrub. Conversely, when it is not pruned, the buddleia tends to become bare at its base, and its flowering becomes less regular.
The butterfly tree flowers on the wood of the year: severe pruning stimulates its flowering, and allows you to obtain an elegant and very compact shrub. Copyright (c) 2020 Tommy Larey/Shutterstock. No use without permission.
Also read: The butterfly tree: a paradise for pollinating insects!
How to prune the butterfly tree?
For
training pruning,
cut the branches above 2 opposite eyes, approximately 50 to 70 cm from the ground. This first pruning allows you to define the framework, and therefore the basic structure of your shrub.
For
winter maintenance pruning,
follow these steps:
shorten the branches of the previous year to about 10 or 15 cm from the old wood, above a pair of opposing eyes;
remove weak stems, inward-facing branches and dead wood;
Cut the branches at the top of the shrub short, and keep those at the bottom longer.
Some buddleias (
Buddleja globosa
,
Buddleja alternifolia
) flower in spring, on the previous year's wood. Their size, less severe, can occur 2 to 3 years apart. It takes place
after flowering,
around July, and mainly consists of eliminating dead wood, misplaced or too old, and shortening the branches that have flowered above one eye. For dwarf varieties, just prune lightly: their shape is already very compact!
Always use clean, disinfected and sharp pruning shears or loppers. The wounds will be cleaner, and you will thus reduce the risk of disease. Intervene outside of frost, preferably in dry weather, under bright sunshine. Cut at an angle to promote good drainage of rainwater.
Some buddleias flower in spring: their pruning, less severe, can take 2 to 3 years and will take place after flowering, around July. Copyright (c) 2022 Wut_Moppie/Shutterstock. No use without permission.
Should we remove faded flowers on the butterfly bush?
It is entirely possible and even advisable to remove butterfly bush flowers as they fade. This gesture helps stimulate flowering.
Non-hybrid varieties tend to reseed spontaneously, and can become invasive. In this case, it is necessary to
remove the faded flowers,
in order to limit its spread.
Some gardeners prolong the flowering of the butterfly bush by removing about half of the young stems around May-June, before the clusters form. This gesture, which is not obligatory, allows flowering to be staggered until October.
Can you cut down a butterfly tree that has become too big?
Good news: it is entirely possible to
cut down an old butterfly tree
, or one that has become too large. It will easily start again from old wood. To practice rejuvenation pruning on your buddleia, also carry out in winter:
cut back all the branches of the shrub to about 30 from the ground;
keep 2 to 3 buds at the base of the stems of the year;
Completely remove weak, misplaced branches and dead wood.