Buddleia davidii varieties in containers?

Do any work, or is it just a silly idea?

(You see them growing pretty well out of gutters, cracks in walls etc!)

 

The wild one [which is what you'll be seeing] will seed into almost anywhere, but it isn't the same as the cultivated types.
I've had a B. davidii Black Knight [grown from cuttings] in a large container for a few years, but I've just planted it out. The main problem is keeping them happy long term in a pot. Mine is now in a raised bed - about 60cm x 60cm, open to the ground. It should be ok in that.

 

Aren't the Buddleia Buzz series meant for containers?

 

Supposedly, but many people seem to find them getting just as big as the usual types.
Not used them myself though.

 

I have four of the Buzz variety growing in my borders. They do tend to grow quite wide even with annual pruning. One would be ok in a pot probably for a couple of years but then i think you would find it needs to be planted out.

 

Yes, you can grow Buddleja davidii in a container.
The following points are worth noting:
The new ultra-small cultivars often have problems and are short-lived. Most should never have had a commercial release. Unless you are committed to a régime of constant care, they are best avoided. But choose a smaller (not mini), named cultivar.
Buzz® plants are almost normal size when planted in the ground, but can become woody and sparse in a pot.
Use the biggest container you can, and watch out as Buddleja will root through the drainage holes into the whatever the pot stands on very, very quickly. They love gravel, for instance.
Choosing the right substrate/compost is tricky. John Innes is too heavy, peat-free is not suitable (especially coir) and peat-based composts also don't always suit for long term growing. You really need to mix your own by adding grit, sand and/or perlite to a mixture of top soil and a good quality general purpose. It must be free-draining and moisture retentive, otherwise the the roots will rot and the plant will wilt. They're not drought resistant in a pot in the summer. And need to be on the dry side in the winter.
Pot-grown specimens are more prone to disease and pests, including the dreaded Melon-cotton aphid. Vine weevils will lay eggs in the friable compost. And, generally, the plant will not be as long-lived as a free-living Buddleja.
The compost will need some renewal every spring and the addition of a high potash feed. Pruning should be in April.

 

@floralies I have Buzz Ivory in one of my raised beds and it grows to at least 2m even when it's been pruned to around 30cm in the spring.

 

I think @Februarygirl much depends on climate/conditions. We have had a very wet winter and spring and mine are smaller than usual at the moment, they would normally be taller, in fact I'm surprised they are starting to flower at all!

 

Thanks to @The Buddleja Garden and everyone else. I've decided that Buddlejas in containers is not for me!