Buddeleja Davidii (I think)

Got one of these in my garden and its quite large, about 8ft tall roughly. I don't know if the previous owners of our house pruned it at all but how do I know if it needs doing, when do I do it and how much do I cut off? It looks very woody and theres loads of what looks like old branches that have just died in the centre of it which break off very easily. I want it to look its best so I'm grateful for any advice. Thanks

 

Hi Caz,
Buddleia's are pretty much indestructable. You can prune them down almost to ground level and they will re-shoot. Personally, as it sounds like a mature shrub I wouldn't prune it down any lower than 2ft, it sounds harsh, but they are fast growers. It will bounce back next spring!

Cut out what you think is dead wood completely. You can prune it now if it's finished flowering, but I would leave it until the autumn. If you only want to tidy it up, you can do that now.

 

Here's what I would do:

1. Cut the dead wood out, as close to the ground as you can get.
2. Any flowers that have gone over, follow the stem down from the flower to the first pair of side shoots, and cut just above those side shoots. On the longer branches, you could cut a bit lower, but be sure to leave plenty of side shoots. Buddleja Davidii can still flower right into next month, so I would leave those side shoots to grow flowers.
3. At the end of september, give it a brutal haircut, to about 2ft above the ground. If you feel that's too extreme and would leave a void, leave a bit more on.
4. In late february next year, give it a very brutal haircut to about 6 inches above the ground, or to the lowest sign of green growth, which ever is the higher. It will very quickly grow back. It will be back to 6ft tall by mid summer.
5. As next summer progresses, keep it trimmed to the desired height and spread, always leaving side shoots on below each cut, and keep cutting off any flowers as they start to go brown. That will keep it blooming for the rest of the year.