I know that I've sworn up and down that this butterfly bush and that is the best one we've grown this year. I haven't been able to make up my mind and keep it that way for more than a week. I thought that for the benefit of anyone who wants to plant one of these extremely useful shrubs I ought to do a run-down of the butterfly bushes I've grown in my yard. Maybe that'll help me collect my thoughts as well.
Petite Plum a.k.a Nanho Purple a.k.a Monum: Nice medium purple color, wonderful fragrance, grows very, very tall in spite of its name. Big flower spikes. My only gripe is that the color is a little generic. If you want a purple butterfly bush this is a good choice.
Miss Ruby: Gorgeous fuchsia color, little to no fragrance. Flower spikes are a little on the small side, but the orange eyes are very striking. Beautiful silver-green foliage, compact habit. My only gripe is that the color fades a bit in the sun. Also, I wish it had a stronger fragrance.
Pink Delight: Huge, impressive flower spikes of nearly pure pink. Nice silvery-green foliage, little to no fragrance. Does not fade in the sun. An overall striking and gorgeous plant.
Ellen's Blue: Exceptionally beautiful slate blue color that shimmers on cloudy days. Good fragrance. Nice compact habit. The flowers wrinkle a bit in the sun. I hear this one isn't as cold-hardy as the others. We'll see.
Peach Cobbler: Massive peachy-pink flower spikes. Lightly fragrant. A slow grower that doesn't produce as many flower spikes as the other bushes. For those who live in areas where butterfly bush is considered a noxious weed, this one is supposed to be sterile.
Black Knight: Lovely deep purple flower spikes. Lightly fragrant. It has a weedy habit, and for some reason the bugs like to chew this one to pieces. Aside from its beautiful color, I don't see much reason to recommend this one. It has its good days and its bad days. In general it isn't as tough as the other bushes.
Royal Red: Pretty red-purple color that shifts to regular purple in certain lights. Very strong fragrance. The butterflies love this one. It's an old cultivar and perhaps not as vigorous as the newer varieties, but it is still tougher than Black Knight. My only gripe is that it isn't particularly unique. One of its children is Petite Plum!
Honeycomb: Very unusual yellow, globular flower spikes. Very vigorous where we planted it, much wider than it is tall. My only gripe is that it doesn't smell very nice. It is awfully pretty, though. I heard that it's only cold-hardy to Zone 5, so I'll be mulching it heavily in the winter. Apparently it's very popular in the U.K., because of its unique color and the fact that it's less invasive.
White Profusion: Very large, pure white flower spikes and an almost tree-like habit. Barely fragrant. Supposedly, there are some butterflies that only like this one. Its advantages are the same as its disadvantages; the white flower spikes don't stand out very much, but they look nice with other flowers.
At this point, I'm thinking that Pink Delight is the prettiest one. Even if it doesn't have a fragrance, look at those flower spikes! They look like they'd be able to stand up to a nuclear blast!
EDIT: To sum up--get Petite Plum. Get Miss Ruby. Get Pink Delight. Get Honeycomb.