Lilac does not require any work except when they get very large and you want to rejuvenate them. Buddleia require yearly cutting.

With regular water, buddleia bloom all summer though. I tend a white one at the public garden. It needs to be deadheaded weekly to remove the brown mess. I would've deadheaded it anyway to prevent seeding (invasive in VA). Originally there was a row of 5 and one or two succumb to winter each year. No, they won't be replaced. Lilac is a long lived plant but buddleia dies easily here. Positives and negatives.

I love butterfly bush, but I don't think they're prominent material - the foliage is rather weedy, best planted in a mixed planting where other plants will hide or take the focus off the foliage. In my area, butterfly bush doesn't bloom all summer - it doesn't get going until mid-summer, and yes the spent blooms can look cr*ppy if not deadheaded, especially since they're so large. Still, I love the darn things! I adore the scent, and the butterflies, bees, and assorted insects are usually all over them.

I'm not a fan of lilacs for hedges, either - once they bloom, they're aren't very interesting, the foliage is nothing to write home about, and they quickly become overgrown with a lot of dead material if not pruned every so often. I would go with some type of Vibirnum for a hedge, rugosa rose (there are white varieties available), or perhaps a panicle hydrangea (PeeGee type - Hydrangea paniculata). If part shade, a hedge of Annabelle hydrangea will be a knockout and extremely easy care (hack them down every year, they bloom on new wood, and are very hardy), but you need soil that isn't dry.

Hi Reese!! I love butterfly bush and grow quite a few. Some are weedy looking ( black knight is especially so ) . But miss molly has been exceptional!! I think it's gorgeous and would make a great hedge.

I grow white profusion. It is new to me and I will say I was just telling my mom the other day how I like it but the brown on the flowers I don't like. It starts from the bottom and works it's way up the panicles . I'm glad I have it but would not want a hedge of it .

Heres miss molly

I do shape mine in the early spring once they have gotten the height I like.

I also have a blue one but I don't know the name :( . I think it's Adonis blue but I lost the tag. It's very pretty too .

Good luck!

I almost bought Miss Molly at a garden center the other day. She is allowed in Oregon as she is seedless. Nice color.