I cut mine back to nubs in late March and they have completely filled in and are beginning to bloom now.
I always try and get to them before they start pushing new growth in the spring because a late prune slows them down.

You have not filled out your zone information so I am unable to speculate on your specific time table. Most all questions you ask on GardenWeb can be better answered if you fill out your zone information- as it stands you could be gardening in Antarctica for all I know :)

That said- yes, they will fill in.
They're very resilient shrubs.

did you shear it... or take full branches near the ground???

otherwise.. it will fill in..

ken

Thanks for all of your replies. By the way, I am in zone 5A - didn't add that before. I didn't prune the branches close to the ground or anything like that, I just "shaped" the foliage using electric pruning shears because they were getting really large. The foliage is still on the top but now the sides are bare with the woody structure showing.

Cathy, last June or so, I asked about my Lime Mound Spireas that were way too large. Folks on this forum said I should do rejuvenation pruning on them. I did, cutting them to about 10". In no time they put on new growth and looked wonderful. I highly recommend this.

Also, after I'd completed the pruning and could see the bases clearly, I discovered quite a few small plants that had rooted themselves. Dug these out, replanted, pampered a bit. Very little work with great results.

HTH, Rosie, Sugar Hill, GA

whats going to happen.. is that at every shear point.. you are going to get 8 to 16 inches of growth.. and within a year or two.. the thing will have collapsed to the ground..

and you will be back here.. asking about REJUVENATION PRUNING OF SHRUBS..

google that.. and cut the cycle short

or do what she said.. and cut it all to the ground right now.. it will knock your socks off.. how fast it regenerates this summer ...

ken

It's kind of scary to think of whacking it down so much (They are very large - I would say 2-3 ft.....but if that is what you recommend I will consider it.

Don't worry they respond well to pruning. I used to cut mine back in July about 6" or so to get another set of blooms.

I never had them long enough for rejuvenation but I see people with ratty spirea all the time and I just think...if only I could give em a quick call to tell them to cut the plant to about 12" off the ground and they would look like new.

"It's kind of scary to think of whacking it down so much (They are very large - I would say 2-3 ft.....but if that is what you recommend I will consider it."

I'm tellin' ya... mine are three feet tall already and when I cut them back earlier this spring I doubt I left six inches.
They come back better than ever!

I cut mine back in early spring to about 1 foot tall. They get nearly full size in no time. By cutting them back severely so early in the season, they do not look sheared because the new growth fills in naturally and a bit unevenly. The later and lighter you prune, the more they will look pruned.

Then, after they bloom, sometimes I will cut them back yet again removing about half the height. It depends if the spent blooms look messy or not. (and my mood?)

Is it better to cut them back in the fall or early spring? Would it be a mistake to cut them back now?

I had asked this on another thread. I will cut mine back this weekend and see what happens.

I planted 3 gold mound spirea in May. They started out fairly well. Now 4 months later they look terrible. Brown leaves on top, bare spots. What is happening?

without a pic./... all i can guess is lack of proper water ... and its fall..

if you can post a pic.. start your own post.. add some pix.. and perhaps more specific info ...

ken