WHAT NOT TO DO IS AS IMPORTANT many times as what to do each season, the dont’s as powerful as the do’s. Nowhere is this more to the point than with pruning, the “there’s no turning around now” portion of horticulture, where you can’t glue it back on or wait a few weeks for another (forgiving) flush of foliage, as when you give a ratty perennial or annual a needed haircut. Are you feeling scissor-happy? Read this first.
Each May and June I’m asked, “Why didn’t my lilacs bloom?” only to find out in the next sentence that the questioners had literally nipped the plants in the (flower)bud with late summer, fall, winter or earliest springtime pruning, long after the new year’s blossoms had been set.
Early bloomers flower on old wood. Go out and look at a forsythia or a lilac: Unless you pruned in summer or fall, you’ll see flower buds already in place, dormant but there. If you prune now, it won’t flower now. Make sense?
Generally speaking, don’t prune spring-blooming shrubs and trees more than a month or so after they finish blooming. After they’re finished flowering, prune immediately. You will not kill the plant by pruning a little later, in many cases, but you will be deprived a season of bloom, so why not first enjoy it?
Woody plants that flower late in the season, such as Hydrangea paniculata, bloom on new wood. Again, go out and look. You don’t see any flower buds now, in early spring, do you? Discovering where on the stems and when the plant creates its flower buds will help direct your pruning efforts.
Details, details:
Lilac pruning: Unless the shrub’s a neglected wreck in need of rejuvenation, cutting off bouquets of flowers is all the pruning you’ll want to do. I never prune them here in my Zone 5B climate after July 4, and like to finish up earlier. The details are here (and there’s a glossary of my favorite varieties, too).
Viburnum pruning: Less is more. Please don’t think of my favorite genus of shrubs (and great bird plants, too) as hedge material to shear and mutilate. Here’s the protocol.
Fruit-tree pruning is an exception among early bloomers: With apples and the like, what you’re working toward isn’t as much the pretty flowers as an architecture and openness that can carry and ripen maximum fruit. I prune in late winter, knowing those are apple blossoms-to-be I am cutting off. Read my method.
Roses: If I had any (well, I have three, mostly R. rubrifolia that I grow for its blue foliage) I’d be on the alert right now, as winter transitions to spring. Many common kinds of roses are pruned when the forsythia blooms. Read how the pre-eminent rosarian of the day, ex-Brooklyn Botanic Garden rose-garden curator Stephen Scanniello, approaches it.
Clematis: I like the ones that like to be cut back hard in spring, to about 18 inches (and frankly I treat a lot of others this way, perhaps delaying their bloom time but never seeming to kill them). Here are a few I deal a heavy hand to, and one that blooms in early fall that I am similarly harsh with.
Weigela: Some shrubs, including weigela, hate being cut back part way, and are better pruned thus: Remove a portion of the oldest stems near the base, to allow younger wood to develop fully. Weigela look a mess when cut back at midpoint, as do Buddleia. If the weigela has really outgrown its space, cut the entire plant to about 12 inches from the ground right after flowering (or earlier spring if you like, skipping the bloom) and it will regrow.
Buddleia: Off with its head, now. Just before the buds want to break, cut the most familiar kind, B. davidii down to near ground-level. Even though in some gentle winters it seems as if it will break higher up, it will look like a hell of a mess without a hard cutback, trust me.
Twig dogwoods and twig willows: Grown for their colorful twigs (you can see some of mine in fall with golden crabapple fruit here), these tough creatures can be cut to near the ground every few years if they grow out of bounds, or you can thin selectively, removing some older stems at the base to let new ones come through. If their color isn’t as good anymore, give them a thorough cutback, or stooling, to promote younger more vibrant wood. Prune in late winter or earliest spring if needed.
Hydrangeas: I’m going to leave this hot topic for a whole separate story, but generally speaking, prune the mopheads (H. macrophylla, the big blue ones) after they bloom in summer, but before they set next season’s buds. How? Cut out the oldest stems to the ground to make room for new ones. This one’s a trickster to normal thinking, because though it blooms relatively late, in most varieties it does so on year-old wood, so it does carry flowerbuds over the winter. Deadheading is always allowed.
With Hydrangea paniculata, the ‘Pee Gee’ and ‘Tardiva’ and other panicle types, a different thinking: they bloom on new wood. Prune them in spring just before new growth begins or thereabouts. They can be cut back quite hard, and still make new wood that then gets buds and blooms. Or you can skip pruning altogether, if you like.
Where to place your cuts can be confusing. I have had ones I didn’t cut back enough turn to octopuses (octopi?) and really look a mess, and this is inclined to happen on older specimens that have been cut back again and again. I’ve also cut old ones back too hard and had to suffer through some gawky recovery years.
The “secret,” if there is one: To get a good-shaped plant, you will often be cutting back to a mixture of oldest (thicker) wood and younger (last year’s) wood, which is counter-intuitive. The pruned structure will look odd, but try to think only in terms of creating a framework for emerging shoots that will then be topped with flowers. Your cuts indicate to the plant where it should (please) sprout from. Let go of the fact that the wood you’re leaving will be of varying thicknesses, not some perfect-looking architecture.
As for the oakleaf types, I either don’t deadhead at all or if they need pruning I do it right after bloom–not later. If they are overgrown, take out some of the oldest stems at the base, as with the blue mopheads. When I used to grow H. arborescens ‘Annabelle,’ I cut her to the ground each year (like the panicle types, she blooms on new wood, so how much you prune is up to you).
Want to hear the contrarian position on hydrangea pruning? As with all gardening, part-art and part-science, here is one, and it’s from a very impressively credentialed individual, Dick Bir of North Carolina State University, whose point of view is summed up here.
And then there’s just the matter of general pruning: Anyone can do at least a good job of basic pruning. Not doing anything is much worse than following these easy steps.
One time I never prune anything hard: in fall. Encouraging new shoots so late in the season is inviting damage to soft new tissue when frost comes. So I time all big rejuvenations for early to mid-spring. But each in its good time. Agreed?
Related posts:
I confess that I was feeling guilty (and scissor ready) because I did not prune anything last year. Thanks for the great advice. Now I know what not to do with my lilacs.
Welcome, Elsa. When I am feeling overwhelmed I remind myself: Go out and look at the branches and see what the plant is trying to tell me. (Sometimes I still get overwhelmed, but usually it helps guide the way.) Glad to see you, and hope to see you soon again here.
Thank you so much! Not that I never read it before, but it’s good to refresh the memory from time to time. Easy reading, well written.
Thanks for the tips Margaret. I’ll see if I can tell the difference on my Hydrangeas. Any suggestions for over grown Cranberry Viburnums? Every Spring I can’t bring myself to prune them and now they’re 12″ tall. I may have to bite the bullet this Spring and the be ruthless.
Thanks for a terrific site.
Russ
Welcome, Russ. Funny you should ask…I have butchered overgrown cranberrybush viburnums and their close cousins, as I confessed in last year’s viburnum-pruning post, I think. Right now (or pretty promptly, before growth begins preferably) cut them down near the base. Brutal, yes, but they will regrow (or at least mine have). Whatever you do, don’t go halfway with them….what a mess. Brutish is better. See you soon again.
Hi There – I’m in Washington, DC .Do you have any advice on when to prune a fig tree/bush (i.e., one of ours is rather bush-like with multiple trunks, and the other has one main trunk). They grow lots of leaves, but we are having trouble getting good fruit crops. We’re wondering whether some judicious pruning in the fall might lead to a stronger, denser growth with more fruit in the spring. We wouldn’t prune right now as whatever ever fruit there will be has already developed on the current branches and buds. We also wonder if there is anything to use as feed/fertilizer to help it set and ripen more fruit. By the way, I know that this is not just a geographic area problem as a friend has several figs that bear heavily all summer. His original plants came from Italy, sent by friends in the mail (basically just as “sticks!”). I am thinking that it may be all, as real estate agents say, an issue of “location, location, location!” The figs are located in safe, protected spots against walls (and thus winter over quite well), but perhaps they’re not getting enough sun per day?
Welcome, Pam S. I have never grown figs, owing to my climate, though technically there are some I could try if I protected it in winter, like this one. SO I have no first-hand experience. Were I to try, I’d probably start on this wild but information-filled website, Figs4Fun, which has growing information and so on, and also read these tips from the California Fig Growers Association, and also this more horticultural how-to from the Royal Horticultural Society in England as a start, and see what it adds up to (full sun, heavy feeding, it sounds like, and according to the RHS a deliberate pinching/pruning system). The growers’ group recommends specifics on the fertilizer and soil ph. And you never know, I may do some homework and learn more along with you. See you soon again.
Hi Margaret, love this information. I’m in Australia and I cut my buddlia davidiis back after flowering but I also have 2 that flower late winter (not late summer). They were here before we moved in and had probably never been pruned and the bases are very thick. We get cold winters but no snow. When should I prune and how much should I take off? Happy First Birthday! Karen
I happened on your website and i love it. I am learning allot about what I don’t have down here in new orleans to grow. All the things i lust after…peonies lilacs etc…you get the drift….no seasons but always flowers and green… much different gardening than yall…I am always amazed and infatuated with the differences…so it is a little like a foreign language reading about yall’s gardening..but the desire is the same!
Welcome, Doretta. I have been to many gardens around Louisiana, and what I remembr most was the oakleaf hydrangeas, and how giant they grew there and how beautiful. (That was the first place I ever saw one, like 20 years ago.) Thanks for your visit and do come again soon. We will share our lilacs with you soon. :)
Hi, Margaret! My husband’s problems have begun to overshadow the pleasure of gardening. But I’ve cleaned up all the winter debris and even planted some seeds (lettuce, snow peas, parsley). I’m slowly bringing my neighbor’s lilac back to life. The few thick branches left by a terrible pruner years ago are dotted with thick buds. I’m wondering if I should cut it back even further to encourage growth lower down. There’s clearly a lot of life left in it that just needs a chance. I’m also wondering when and how one should prune holly (ilex). When, I assume, is now. But how when they’re fairly shapeless? Their maximum height at the moment is about 4½ feet.
Really great information and links, Margaret. I know a lot of gardeners will be bookmarking this page for later use. I put it in my ReadLater box myself. Always good to check when I’m not sure. However, I think I’ve got the rose pruning down after all this time. LOL.~~Dee
Hi, Dee…and yes, I expect you might be on auto-pilot with the rose care over there. Here, not so much; I have to talk myself (out loud) through the angle of the cuts, since I have so few roses to practice on. Each to our own addictions, right? Happy spring.
Margaret:
Love your site, what is your opinion on crepe myrtle in Northern NJ? Any particular species and if I have partial sun about 4-6 hours- is one species better than another for this area?
Welcome, Suzanne. Local nurseries will be able to guide you as to cultivars that are a bit hardier, which is probably all they would dare stock (such as the various ones from the National Arboretum breeding program). Read the middle portion of this page from their site. I am so cold I do not even try them, but have seen magnificent ones on Long Island and elsewhere near NYC.
Margaret
You say to deadhead the daffodils now because of the terrible heat. OK when I cut do I cut below that bulbous thing just under the throat of the flower or leave it and just snip the actual flower. I know the leaves feed the plant so do tell
THanks
WIX
@Wici: I just snap off the spent flower iteself with my fingers (you can also use a snips/pruners of some kind) but I leave the entire flower stalk and all the foliage until about July 4, when it starts to wither of its own accord. The Flower-Bulb FAQ page has full information about this aftercare.