“When is the best time to prune Buddleia?” Question from Angie of Fort Bragg, California
Answer: In your coastal Mendocino County location, I would cut your butterfly bush (Buddleia spp.) back when your cool, wet winter hits. Butterfly bush does not look its best when chillier temperatures hit, even though it remains evergreen to semi-evergreen where you live, so prune it back by 1-2 feet once it stops blooming well, and its leaves start to flag. This will also make your garden look tidier during the chillier months and result in a more compact shrub. And, because it blooms on new wood and grows post-pruning quickly, you can feel confident that the shrub and flower buds will not be harmed.
Another factor is that butterfly bush self-sows prolifically and is considered invasive in your area. Pruning it back and removing its old buds before seedset will also reduce the chance of spread in your garden and beyond.
I hope that this information helps!
Happy gardening,
Jessie Keith
Black Gold Horticulturist