Summer-flowering shrubs such as the butterfly bush (Buddleia davidii), is also known as summer lilac, the shoots are cut back sharply in late winter to promote the abundance of flowers. This is because flower buds develop only on the young shoots that sprout in the spring before flowering. That’s why you cut them back so severely after winter. To do this, each year in the spring, the flowered branches of the previous summer are shortened to a length of about 30 cm, that is, you leave two to three eyes.
If this seems too much, you can also simply thin out the shrub by cutting out individual branches. However, flowers will really only appear on the young shoots. So you have to expect a little less blossoms.
Basically, the more you prune, the stronger the shoots and the larger the flowers.
Forgotten pruning – and now?
If you forget to prune in late winter, it doesn’t matter. The shrub will only grow quite large and will probably not bloom as abundantly. Next year you will have to prune a little more.
By the way: After flowering in summer, the shrub only needs a little fertilizer. Compost is enough here, carefully worked in with a digging fork without damaging the roots.