when and how much to prune back large butterfly bush, etc.

[green]

I have a butterfly bush that I have not trimmed back for two years. It is about 5 ft tall and 4 across. It is blocking growth of flowers under it, but we like the height for screening the view into the house from neighbors back yard. How much and when is the best time to prune it back. Also similar situation with salvia greggi.

thanks

[Tony M]

green-
You can moderately prune both of these at any time but winter is the best. The salvia should not be pruned severely, you can kill it. I like to wait till early spring and then prune back to green growth. I trimmed a 5 foot bush back to 18 inches and it grew right back that summer. Here's the thing, butterfly bush is a big, fast growing plant. You can trim the lower branches to give the other flowers a break but it will grow right back. Try not to put yourself in this situation, either transplant them or, if annuals, don't replant.
Tony M

[sjthornton]

I'd like to transplant my buddleia this fall - I planted it in the spring and I'd like to move it to a better spot. Can I do that soon or should I wait till spring?