There are a several kinds of cutting back. One kind is done in early summer to encourage bushy growth or control size. Another is done after blooming to tidy up or encourage rebloom, and is often referred to as deadheading. Then there is the clean-up, done either in fall or spring. The link below is a good guide to deadheading.

This time of year, everyone is talking about cleaning up. In my garden, bleeding hearts turn yellow by late summer, and I cut the foliage to the ground. Hopefully, I've planted something to take its place, or I'm left with a hole where it used to be until spring.

Peony foliage can harbor botrytis blight, so once it dies back, I clean it up and put it in the trash. Same with the Phlox foliage and stems, which are prone to powdery mildew. Better to clean up and discard any leftover bits.

I leave butterfly bush until late winter/early spring, at which time I cut it back hard. Some books say to cut them almost to the ground, but I lost one this way, so I cut it back to a couple of feet tall.

Do a search of this forum for previous threads on "cutting back". Also do a web search for the websites of Horticulture Magazine, Fine Gardening Magazine, and Garden Gate Magazine. They have some good online articles you can read for free. Better yet, if you're going to garden, subscribe to a couple or all three, or ask for subscriptions this holiday seasons as gifts! Renewals next year are almost assured if you drop the hint to someone who never knows what to buy for you.

Here is a link that might be useful: link

Hello, Terri: I cut back in the fall, simply because in spring when the snow melts, nothing is more awful and messy looking than a garden that did not get trimmed in the fall. Iris: cut down to about 4 or 5 inches of foliage, get rid of any dead leaves. Better to bag iris foliage and put in garbage, don't compost, bugs might be hiding in there. Phlox: cut the stalks down to about 1" from the ground. You will see the start of next year's growth below that, if not right now, then within a few weeks. Peonies: cut to about 1 1/2 inch from the ground, but wait a few weeks, till mid-October, say. The new growth will come from below the ground in the form of bright red sprouts. Butterfly bush: wait till later October, when it is finished blooming. Trim the stalks down to about 1 foot tall. If you have any doubts that it will survive the winter, mulch. Bleeding hearts - you can cut all this right down, the spring growth will come from below the ground. Deciding what and when: as you gain experience as a gardener, you will come to know which plants have foliage which is evergreen and just needs a trim, for example, sweet williams and pinks, shasta daisies, daylilies, penstemons, lady's mantle, lamb's ears, etc. and which ones will start again from below the ground: example, hosta, peony, bleeding hearts, and so on. Nothing beats lots of observation.

see the thread "your vote- when to cut back: fall or spring"

Do not cut back Buddleias (Butterfly bush) until mid spring. Many plants have been lost from fall or late winter cutting. Other plants not to cut back until early spring are Perovskia, Gaura, Caryopteris, and the western (dry winter) Agastaches (A. foeniculum can be cut in fall.)

Anything else can be cut back in fall. I leave tall sedums and the grasses, of course, because they add interest to the winter garden.

In the fall, I do as noted above - peony and tall garden phlox cut down and put into trash. I cut back daylilies, Asiatic and Oriental lilies, Veronica, nepeta, hosta, artemesia, bleeding heart, feverfew, iris, black eyed Suans, and platycodon (balloon flowers) and all of that goes into the compost pile along with the season's annuals.

I leave all varieties of dianthus as they are and leave sedums for their color until they get covered by snow.

Anyone know about hardy fuchsias? Is it safe to cut them back now or should I wat til spring, as I usually do? I'm expecting a baby in the spring, so anything I can get done now will help!

I don't have an answer about the fuchia, but I DO think it's (technically) a sub-shrub, so I'd leave it until spring. OK, I could not resist and googled this, and the one site I checked said to cut them back in spring or not at all, for those that keep their stems and leaf out from those instead of just from the base of the plant.

Ah, righty-oh. I won't risk it then. Thanks!

I cut almost everything to the ground in the fall, because my husband has a chipper/mulcher machine and grinds everything up to make a huge pile. By the time spring has truly come to VT, I have a lot of homemade compost that recycles everything from the previous year! It also has the advantage of eliminating many bugs and diseases harboring in the old foliage.

Some plants should have foliage and stalks removed to avoid disease--peony and iris to name two. There is evidence that some plants use stored nutrients in the dead stems to begin their next spring growth. That's one of the reasons I don't cut everything back in the fall. Another reason is that birds will visit the winter garden to eat seed heads on your plants.

The good news is that if you want to cut back, it probably won't kill any plants. Roses are an exception. Do not cut back any rose canes until new growth appears.

I am wondering...is there any reason why I can not wait and cut-back all of my perennials in the spring?
Thanks!

Right about now, I usually do a lot of deadheading, and am normally meticulous about this. But this year, I am being lazy and procrastinating a bit, and am not really minding the spent flower heads on the Miss Kim Lilac and the Buddleia. Towards the end of the season I will stop deadheading on some things like Cosmos, Gaillardia, and the Echinacea to leave seeds for the birds.

Another thing other gardeners recommend is shearing back plants like Salvia after their bloom. This will deadhead and tidy up the plant, and encourage rebloom. I can't stand the smell of Salvia nemorosa, so I haven't done that this year either! But I have a few plants that need this treatment out there right now.

I cut back most things in the Spring. I enjoy the winter interest, the stalks catch leaves for mulch, act as a slight wind break, provide habitat for overwintering insects (mostly beneficial I figure), provide seeds for the birds, and I don't mind the messy brown stalks. It's more interesting than looking at a bare expanse.

There are exceptions, and these get cut down in the fall - Peonies, Lilies, anything affected by disease, and some really scraggly ugly things.

I like to leave the coneflowers until spring (even though they reseed everywhere) because they look pretty with the winter snow and they are good food for hungry birds. I always regret it later when I am hoeing out thousands of seedlings all summer, but I keep doing it anyway. :)