For years I have been reading about the Chelsea chop. I am sure most of you already know about it, but for those who don’t, bear with me. Around the time of the Chelsea Flower Show, (the end of May), you give some of your plants the Chelsea chop, cut them back by a third to half. This makes the stems shorter at flowering time, so you do not get the dreaded sprawl. I have a sedum that does this, every year it gets top-heavy and just falls over with a big ugly centre. So I gave it the Chelsea chop. Not the whole thing, I wanted to compare, so I just chopped one half. And it was so much fun I decided to try it with my Phlox ‘David’ as well.
It might have been a bad year to try this for the first time. If we hadn’t had the drought this summer, perhaps the chopped back plants would have got taller.
The phlox was great, I had twice as many flower heads on the chopped back stems, but they were a bit short.
I think I shall try this again next year and see if they get any taller, fingers crossed there is no drought.
However the sedum was not a success in my eyes.
The chopped back side did not get the lovely dark colour it was purchased for, and the flower heads are much smaller. It will not be chopped back again.
How about you, has any one else tried the Chelsea chop?
(Still experimenting with photography, first sedum photo taken early in the morning, the second mid morning, which do you prefer?)
I am a floral designer living in a tiny condo in downtown Toronto, Canada's largest city. But on the weekend, I am a gardener/frustrated architect trying to keep up with a 3/4 acre garden in Owen Sound, Ontario, a warm (to Canadians, Zone 5b, and a cold (to Americans, Zone 4b) garden.
Green Theatre 
Flâneur Gardener said,
September 5, 2012 @ 3:53 AM
I haven’t tried it, but looking at your sedum I’m actually considering trying that on mine next year; they flop over so much so that some of them are just lying on the ground. (Of course mine is not a dark-leaved sedum, so I wouldn’t have the issue of paler leaves.)
kilbournegrove said,
October 16, 2012 @ 9:01 AM
Let me know if it works for you.
Flâneur Gardener said,
October 17, 2012 @ 12:56 AM
As it is, I can definitely see that the sedums I’ve grown from cuttings are much denser and lower – with less flopping – than the ones that have grown in the garden for years, so I think this effect could be reproduced by a chop.
(When using them in flower arrangements I simply leave them in the vase until they root; they stay fresh-looking so much longer than any other flower, so you can continue to “refill” with other flowers to keep it good-looking. Then when they have rooted I pot them up for a few months and then they’re good to go in the garden.)
paulinemulligan said,
September 5, 2012 @ 4:00 AM
I do it each year with Lysimachia cilata Firecracker and it usually works well, this year however we have had so much rain, the chopped stems are as tall as they would have been. We have loads more flowering spikes though so it was worth it. I prefer your first photo without the bright sunlight, I find early morning light is much softer.
kilbournegrove said,
October 16, 2012 @ 9:02 AM
So lack of rain kept the stems short, I shall have to try again next year and compare the height differences.
Alistair said,
September 5, 2012 @ 7:00 AM
I always do this with our Hypericum magical beauty. I have also done this with our Phlox and although the plants are bushier it makes them very late in blooming in our cool climate. Amazed at the difference in height with your Phlox.
kilbournegrove said,
October 16, 2012 @ 9:03 AM
I think perhaps the drought had something to do with that.
Heather @ new house, new home, new life said,
September 5, 2012 @ 7:33 AM
Did it this year with my sedums and crysanthemums – both are shorter than usual but have beautiful buds ready to bloom. The mums especially like the cutback. Also cut back my spent spiderwort and am now having a bit of a late show with some of them (not really a Chelsea chop, but good maintenance). The phlox in your garden was a surprise – wouldn’t have thought it would have stayed that short.
kilbournegrove said,
October 16, 2012 @ 9:03 AM
Perhaps the drought caused the phlox to stay short?
Barbara H. said,
September 5, 2012 @ 10:33 AM
This is the first year that I cut the four o’clocks almost to the ground when they got so lanky and ugly after blooming for a while. It wasn’t the Chelsea Chop because it was in August, but it sure made for a miracle of regrowth, fullness and new blooms. I’ll be repeating this every year from now on.
kilbournegrove said,
October 16, 2012 @ 9:04 AM
Good to know Barbara, I shall try again next year as well, just to see is it is any different.
Marguerite said,
September 5, 2012 @ 8:55 PM
I always hear about people saying you should cut back certain plants to encourage bushiness but I’ve worried I wouldn’t do it at the right time. May seems early as plants are just getting started at that point here. One of these years I’ll have to just sacrifice something and give it a try.
kilbournegrove said,
October 16, 2012 @ 9:04 AM
Try it next year Marguerite, if you are worried, just try half the plant like I did.
Jennifer@threedogsinagarden said,
September 8, 2012 @ 11:25 PM
I am sorry that your Chelsea chop did not work on the sedum. I chop one of my sedums that always flops if I don’t. I cut it back about a third only. Then I took the cuttings and stuck them in wet soil. I watered well to get them established. Now, I have about 10 new plants and a sedum that won’t flop. The flowers on the mother plant are a bit smaller than they would have otherwise have been. Each new plant is about 6″ tall and has a small flower. I haven’t noticed any color change in the foliage, but my plant is not as burgundy as yours.
kilbournegrove said,
October 16, 2012 @ 9:06 AM
Jennifer, I actually stuck the sedum tops in the Kitchen Garden, to see if they might root, however no water as I was not home. A couple of them look alive still, shall see if they winter over.
Lois Smith said,
September 9, 2012 @ 4:08 PM
In one of Christopher Lloyd’s books (sorry, can’t remember which one) he suggested for sedum flopsy to dig them up in the spring and replant. I have tried the June chop with so so results. My young sedums don’t have the problem. As I don’t have a Fergus, I am going to go around the roots of the old ones with a shovel in the spring to see if that makes a difference. Will keep you posted.
kilbournegrove said,
October 16, 2012 @ 9:06 AM
Do let me know Lois, I am quite curious.
Jean said,
September 19, 2012 @ 10:50 PM
I often cut back balloon flower to get bushier and slightly later bloom. For the past couple of years, I’ve been cutting back the tall Rudbeckia ‘Herbstsonne’ that grows in the fence border; the idea is to make it 6′ tall instead of 8′ and fuller. This year, though, the Rudbeckia chop was a failure. Admittedly, I didn’t get around to it until about 2 weeks after Chelsea (and since we had an early spring, the plants were further around than they usually are). The result of my chopping too much too late was that the cut stems never grew back and the plant ended up looking thin and pathetic. Next year, I’m not going to chop it at all and see what happens.
kilbournegrove said,
October 16, 2012 @ 9:17 AM
Hmmm, maybe that contributed to mine as well, I shall try again and see if it is any different.