Hi Evelyn. I am assuming you are referring to sedums like Autumn Joy and that sort. I typically cut mine back by half once they get about 5 or so inches tall. Hasn't ever affected the blooming of mine. In fact, I can often get more blooms by pinching out the flower heads after they are finished blooming. Really depends on how early they bloom and how late in the season we get our first killing frosts.

I am assuming they don't get too leggy due to insufficient sun exposure.

Thanks Miguel
They are the tall ones....Autumn Joy, Brilliant, Neon and a couple variegated. They'll stand tall for a while then begin to flop. I've got them all in full sun so I know that's not it.
I'll do like you said. Wish me luck!
Thanks again!

Hi Ev!!

How old are the clumps? Mine usually don't get any care at all and they never seem to flop. I have them in medium rich soil in about half day sun. I didn't know anyone pinched them back. Once mine got to be really large clumps they sort of support each other as they stretch.

Hi John!!

The clumps are probably around 6 years old. They are pretty large clumps so I get really large flops...LOL
The soil is pretty rich and in full sun for at least half the day. Maybe the soil is too rich?
I'm going to do the pinch trick Miguel recommended and we'll see what happens.

Evelyn, your rich soil may also be contributing to the flopping phenomena. I have mine planted in straight clay with a little soil conditioner added in when they were first planted probably 8 years ago and I have never experienced the flopping phenomena before except for ones that were originally planted in overly amended soil or were not getting enough sun.

Miguel
It must be the soil. It has always been very rich. I don't have much clay in any of my beds. Only thing I can do is pinch them back and hope for the best. The good thing is that I'll have that many more sedums to root to share.
Thanks!

Really, overall Evelyn, that's a good problem to have-- rich soil instead of clay! Bet most of us would deal with floppy sedums & trade you! :)

Pinching them back and planting the babies is a sure fire way to have loads to share. The ones I have were all obtained by taking cuttings at a friend's house.

Lucky you, I would sell my soul to have good soil although clay isn't really all that bad once you add enough mulch and allow it to decompose down. I would rather have clay than sand! It eats organic matter like nothing else.

Well I have an unlimited amount of mulch....my other half has a tree service. I think I had added a good layer of mulch on those beds before I decided to make them both sedum beds because of the location. I haven't done anything to them since. Every one of my beds have the blackest soil which I was used to when I lived in NJ. I do have sandrock to contend with but it's in my pastures.
If this weather keeps up being so warm...I'll be trimming those sedums this weekend...lol

If you absolutely cant stand it and want to stop the problem, it sounds like some digging up of the clumps is involved, and replanting in sandy loam. Hard work. How about another solution like propping them up with well-placed rocks for a rock garden effect? I am growing a Sedum collection in my perennial border. Luckily, I have sandy loam there, by luck, when I hit a sand pocket here in the red clay Piedmont. But I am also placing rocks in that bed, since it seems to call for a rock garden with all those Sedums. There are so many varieties! Really love Sedums.

That's a little too labor intensive for me. I do like the rock idea and may incorporate a few in the bed. I'm going to trim and propagate the cuttings and see what it does this year.
Thanks everyone for the ideas.
Evelyn

I have one clump of Sedum Neon that I was too lazy to plant one year, so I just heeled it in real quick. Plus it gets some shade. Darn if it doesn't grow sideways and then up and doesn't flop! It stays short. Go figure. I love it.

I have also had the problem with floppy Autumn Joys and I have dozens, all from the 1st one I bought. I used to dig them, then split. Now in early spring when they show their heads, I split them where they are with a spade. If they are close to the house and backs don't show, I split off the back. If they are in the open, I split into 4, i.e, like a square..then slimply plant the splits elsewhere. Easier then digging!

Well, I'm inclined to disagree with the proponents of pinching, except on chrysanthemums which have varying degrees of natural insect resistance on open wounds.

I think every perennial and bulb will annually react to that year's growing conditions and weather. Fast growth during optimum weather often results in slightly weaker stems and lots of top growth.
If you're watching , you know when to provide support with stakes and twine to surround the plant. Helps especially with the hard rain and winds we've had this year. The idea being to protect the crown of the plant from cracking damage when too many stalks flop abruptly.
Just my opinion, I could be wrong but I'd rather have and corral/support the lush growth and abundant flowers in summer/fall than a plant obedient after injury by pinching.

I have same problem. But my thinking about pinching before they get too tall, is that if it saves you lots of supporting and tying and buying of wiry things, it is worth it. Plus, I think of the plant's energy; If you cut it off somewhere, all that energy that's no longer needed must go somewhere. So it grows thicker (i hope). One related idea is: when your perennials' flowers are over, from time to time remove the seed pods. Then when there's nothing much left, cut it back quite low to the ground - 5 - 6 inches depending on what it is. And feed it. In a few weeks you'll have some fresh new growth that will produce flowers. If not, at the very least you'll have fresh green growth in the garden instead of those brown, dry old leaves and dead stalks. Energy has to go somewhere, and as my mother used to say "Cut and come again". Love you Mum.