Cutting Back Perennials
I spent the early part of last weekend doing more fall cleanup, including cutting back some of my perennials. I thought it might be a good time to review which perennials you should NOT cut back in the fall.
Don’t cut back anything considered evergreen. Evergreen perennials include some primrose, coralbells, dead nettle, creeping phlox, pinks, spurge, hellebore, bugleweed, rock cress, sea thrift, wormwood, heart-leaf saxifrage, lungwort, barrenwort, saxifrage, creeping sedum, hens and chicks and thyme.
If you see a clump of green leaves at the base of spring and summer flowering plants, don’t cut these clumps back. These are rosettes and the plants will grow from these next spring. You’ll see rosettes on Oriental poppy, sage, foamflower, tickseed, and jacob’s ladder.
Of course, if your perennial has a nice fall and winter effect, like ornamental grasses do, feel free to just leave them until spring. Be sure to deadhead any flowers, though.
Some other perennials, like asters and joe pye weed provide seeds and habitats for wildlife over the winter, so you can leave those, too.
Your plants won’t die if you don’t cut them back, so don’t sweat this too much. Mostly, it depends on your schedule and whether you’re more likely to have time now or in spring for cutting them back. Personally, I do like to get rid of the ones with dead foliage that’s unattractive, like daylilies. Kind of cleans up the whole bed and, mentally, makes me prepared again for spring.
November 27, 2012 - 1:58 PM
When am I supposed to cut back my lilac bush? I keep forgetting to do it and I think that’s why it hardly gets any blooms on it. Otherwise, it is very large and healthy. Thanks.
Lindsey – you’re probably pruning too late. You should prune right after the flowers have faded. They set the next season’s flower buds almost immediately so, if you prune too late, you won’t get flowers. When you do prune, don’t remove more than 1/3 at a time.
Regular pruning will renew your plants, and keep flowers coming year after year. Newer stems won’t bloom for a couple of years, so you want a balance of new shoots and older stems. As a general rule of thumb, prune out stems when they are more than 2″ in diameter.
I have cut back my iris and then on my roses which have grown really tall, I cut them back to about 3 1/2 feet tall. Karen, what about clematis? I never know when to trim them back. Also, when is a good time to cut back my mums? They have the dead flowers on them and some are showing green shoots at the bottom of the plant.
Update on my attempt to get my amaryllis to rebloom: My plants have started to send up new green leaves, so I have moved them to a bright sunny window and I am watering them again. So far things look good. No sign of flower stalks, yet.
Branching out a bit, can anyone tell me when is the ideal time to root grapes from cuttings? My grandmother would just tuck cuttings in the ground and root them but I haven’t been able to find out if this should be done when I’m doing normal late February pruning, or when the vines are actively growing. My other grandmother would root boxwood cuttings by inserting them in potatoes and planting them. I’m missing some key elements for both processes as I once got a fair crop of new potatoes but have yet to get new boxwoods or grape vines.
Can’t speak for grapes, since I can’t get one to do much. As far as boxwoods, I’ve clipped new growth, stripped an 1″ of bark off the bottom of the new cutting, dipped it in Root Tone and stuck it in a 4″ pot of potting soil and had good luck like that. Don’t get in a hurry. They are sllooww growers.
DC, I usually cut the dead flowers off and save them in a paper bag to get completely dry. In the spring , I spread the seeds off the cut blooms when I mulch. Get a ton of new mums that way.
Oooo – nice idea on the mums, wdbrand. I think I will try that. I hope it is not too late.
Deep Roots – I remember seeing small boxwood plants at either Monticello or Mt. Vernon and they were being sold as coming from the boxwoods on the grounds. They were in little 2 inch pots. I think wdbrand has the right idea about stripping the wood and the Root Tone. Maybe you could put them on your sun porch over the winter. I bet it would take a long time for them to root and grow. What about taking the grape vine and letting it root into the ground – like you told me how to do my lavender plant. Then digging it up; like you might do with blackberry vines.
Doppler Carol – so sorry! Just realized that I never answered your question about pruning clematis. Timing depends on when your particular type of clematis blooms. Here’s a good primer you can check out: http://gardening.about.com/od/perennials/a/PruningClematis.htm
That *is* a good idea for the mums. I harvest seeds from my columbines and share them with friends. No need to really spread them myself because the wind seems to be doing a good job of that.
Thanks for the info about my lilacs, Karen. I’ve actually never cut them back and one of them is a monster. After next year’s blooming, I’ll go after them with the cutters.