I've never had one of these because they are so invasive in my neck of the woods. I've recently purchased a sterile form and would like to plant it in a sunny protected corner where I will enjoy it often. I know these can get quite big and I'm not sure my space is right for it. So, my question is: how difficult/easy is it to keep a butterfly bush on the smaller side? The label indicates it can get 3-7' tall and 3-7' wide. I'd like to keep it to about 3-4' wide, it can get as tall as it wants. Is this a reasonable thing, or should I rethink my location? Thanks.

This is the one I bought: Butterfly Bush (Buddleja davidii 'Asian Moon')

This is not from personal experience but I remember reading an article in a gardening magazine indicating that they can be cut down right to the ground each year. I would give it a couple of years to establish before doing this.

I've often cut them down to 5 or 10" (they get very woody bases and I couldn't cut any lower) but I don't know how it will work, if it can work, to cut the sides to keep them more narrow for the space you have. Just this past Thursday I was cutting the branching sides of one of mine so I could walk past it.

I think the top branches will compensate by hanging low. We can compare notes by August.

I was told to cut them down to 1 foot tall and not all the way down to the ground. They only bloom on new wood so you will not effect flowering by trimming them.

I cut my butterfly bushes down to about 10-12 inches in very early spring (before any new growth occurs). In their first few years they will most likely stay a rather manageable size, but as they age they can put out an awful lot of new growth each and every season. Keeping them a 'manageable size' in a spot that is smaller then it wants to grow can be a challenge as side shoots tend to grow a lot more 'out' than 'up'.

One thing you could try, perhaps, is to use some twine around the plants midsection to keep those side shoots pointed upwards a bit more. You could also trim those sections, but that may adversely affect how those branches bloom. I'm sure they would still bloom, but the flowers would likely be smaller and not as numerous.

Keeping in mind that I live in a very temperate area, where plants usually far surpass the stated height/width, I think it would be better to find another spot for this guy. It's so small at the moment (4" pot) it's hard to picture it at maturity. My neighbor has one, though, and hers is all of 7' tall and wide. Plus, planting too closely is one of my chronic problems.

This is what Greenleaf Nursery says about this particular Buddleja:

"Like the rest of its tribe, Asian Moon Buddleia is a fast-growing deciduous shrub that will require some pruning to keep it fresh each spring. It is best kept within bounds by coppicing or cutting to the ground in late winter, while in late July cutting the shrub back by half will control size and encourage heavy reblooming. Also like other members of the genus, Asian Moon is nearly indestructible, adaptable to gardens from Boston to Florida (U.S.DA. Zones 5-9). Consider Asian Moon Butterfly Bush as an easy-care selection that provides plenty of garden color and fragrance in full sun.

Useful in the landscape for summer bloom and to attract butterflies; used in masses, not as a specimen; can be treated as a herbaceous perennial to give height in the mixed border; or under-planted with low perennials."