Good advice...thank you. Yes, after 45 years in NY I'm well aware that the season is half over. I'm already onto planning for next spring.

They do not flop because they get too tall, but because their stems are too weak. I have tall phloxes which stand up perfectly, and some shorter ones which flop. People often assume that it is the height that causes floppiness. It is not. Salvia nemorosa Tanzerin is the tallest of all varieties, but never flops with me, while some short ones always fall apart no matter what.

Yes, the ones that flop seem more of a wild variety. However, the person who gave them to me, is the person who told me to cut them back...just not sure exactly when to do it.

According to Tracy DeSabato-Aust, garden phlox can be cut back by one-half mid June. I layer some of my phlix for different bloom times, some I just cut back. It does delay flowering by a week or two, but sometimes I just want a shorter plant.

I've never cut mine back, I like the height of them. I don't really get too many that flop because I let the bunches get big and they basically hold each other up. But I would do like Ken said and experiment with different bunches...just remember what you did to each one!!

Seems to me that Martha Stewart recommends removing some of the weaker stalks when the plant is small; the remaining stalks will be stronger and won't flop. I haven't tried it, but if its good enough for Martha.....
Jan

Cutting back Phlox is similar to cutting back Sedum. You get bushier, shorter plants. This year for the first time I bought rooting hormone and tried getting some of the phlox cuttings to root. Only a small % rooted - but I am thrilled because now I have 3 more Laura & 2 more Blue Paradise.

Connie May

yes, in the UK, it is known as the Chelsea Chop as the best time to do it is at the same time as the Chelsea Flower Show (Late May). works especially well with asters and heleniums (and yep, sedum), which will be sturdier and flower a bit later (2 weeks or so) than usual.

Okay, here is a subject dear to my heart..I was gifted with my tall garden phlox about 3 yrs. ago when a friend from church needed to divide here. They are the deep or hot pink color. She's had them so long that she no longer remembers the variety. I have been told to get more blooms not to let them go to seed and cut back right under the faded bloom. I have two more that I feel I need to move in the fall as the soil where they are now is terrible and we have amended it several times and it still isn't great. I had moved the others out in the front flowerbeds where they get afternoon full sun and they are thriving plus they are in better soil. How can I start a cutting from the phlox that are now in bloom? Once I cut back the faded bloom, why can't I cut a section about 4-6 in. and try rooting it? Or do I have to dig up the entire plant and divide it and transplant?

I have a few stands of 2 year old phlox ("Blue Paradise" and "Peppermint Twist").

The BP flowered first and then with significant pinching has re-bloomed with a passion.

But I am extra impressed with a large stand of PT that have been in constant bloom for now about 6 weeks and continuing. I am thinking that this might be due to the fact that these particular plants were located in less than a full sun location. Anyways I am pleased to see such performance.

Yes, you can cut back before bloom - they will be shorter, bloom a little later, and flower clusters will be smaller, but perhaps more of them.

I have too much experience with the deer choosing to 'cut back' for me - they sometimes chomp off the top tender growth before buds form... maybe sometime in June?
they're in full, glorious bloom now... can't help with the 'how much to cut back'... think you can make many things work - ditto with the timing... just keep them 'happy' with some watering, and fertilize if needed...

Beth Z5 Northern Michigan

I got this advice from my daughter who lives in Wy. I had given her a clump of White Admiral-which I consider the best phlox I've ever grown. She told me not to deadhead as the flowerhead would bloom again!! I was amazed when it did. I never deadhead this one anymore.

My experience is to cut them back in mid June to very early July. It works, they don't flop, the purple ones that it. I just got some white ones that are five feet tall and they were not cut this you are stand strong, even after the transplant. Purple ones I will always crop.

I have to believe this is true. A nice bunny chomped mine down earlier in the summer (no leafs left), they even had buds on them at that point. They came roaring back and are still blooming now although the whole plant is much shorter.