If they grow like a regular buddleja, one year.

Like other trees and shrubs do not reach a specific size and then freeze there, remaining alive and healthy yet making no growth.

Like abelia etc. a cane-type shrub that does not make a good long-term, high quality specimen. Good for quick results but for a permanent living fence you will probably need something more along the lines of yew, holly or box.

I agree with bboy, but I'm not sure if you'll be solving the problem here by planting a living fence. You might be adding to it. If your grumpy neighbor doesn't like you spraying grass clippings on his drive way (if that's what you mean by "spraying" then I would suggest simply asking his permission to sweep off his driveway after you mow in order to keep the peace. I have learned that a lot of conflict is caused by a lack of understanding between the two people involved and that conflict can be quickly diffused by talking in a polite and friendly way.
Of course, I say all of that with "tounge in cheek," since I don't know your neighbor or the entire situation you are dealing with. Good luck to you, and i hope things work out.

they were very short lived in my Z5 ...

how long lived will they be for her... ????

if short lived .. she might want to start planting longer lived stock.. for the long term ...

for me.. the MI SOIL CONSERVATION DISTRICT offices.. offer very cheap.. very small plants for wind breaks .. at the proper planting time in spring ... and a site block.. aka neighbor block.. is just a wind block under a different name ... see link.. and research it ...

ken

Here is a link that might be useful: link

The shrubs are already bought and planted so there's not much to do except wait and see.

Personally, I wouldn't have chosen Buddleja for a hedge, even here where they grow like mad and do not die back in winter. They are quite high maintenance to keep looking good. To get healthy, floriferous shoots each year they benefit from hard pruning every spring, or at least every couple of years. And I mean pruning , not running over with the hedge cutters or shears. Very time consuming.Otherwise they become an ugly twiggy mass with leaves and flowers on the ends of branches. In winter they look sad and scruffy.

Hi Flutter,

I hope you planted these well into your own yard. You are going to need room behind them to step and move when you keep the back side pruned away from the neighbors drive. Any that flop over to his side, he has the legal right to cut off and you may not like the way he prunes ( or sprays ). He has the right to not have your plants interfering on his property.

So IF you set them too close, you could still enlarge the bed and move them further into your yard before they get established. Easier to do it now, than create an ongoing issue.

Good luck, I know plants and property lines are sometimes tricky.

Here's an interesting article you might want to review (before your neighbor gets a chance to read it).

Here is a link that might be useful: Butterfly Bush in Kentucky

In England Buddleia is everywhere...sort of like tree of heaven here. All over railroad tracks, vacant lots, etc. One Buddleia is pretty, two are ok and then when you see thousands, all with the lilac/mauve flower you change your mind...

I did offset them 4' from the property line. Also my brothers butterfly bushes don't die back to the ground, they just lose the leaves in winter and come back out in the spring.

36 Buddleias is a tremendous number! And the Nanho series stays quite small, but must be cut back to stubs every spring. What a job to do 36! They will grow maybe 5 feet tall each season.

Lowes speical! I had to go to 2 diffrent stores to find that many. That was the cheapest/fast growing bush they had so I tough what the hay. I payed 4.00 a bush. I hope they bush out well. I looked at my brothers butterfly's and his is the black knight. Im 6' and they are over my head!

Black Knight is a full sized cultivar, and yes it would be very tall. But not the Nanho series. Look it up.