Pruning intimidates many homeowners. Either you're too busy, the work's too hard or you are afraid of making a huge mistake. I can't help with your time management or labor shortages, but I can give you the basics of rejuvenation pruning. Although major pruning is no walk in the park, it can reduce too-large shrubs or can tame a wild hedge back into its allotted--albeit too small--space.
Late winter is a great time to check your landscaping for pruning needs. Besides, with the ground muddy and too cold to work in, what else can you do in the garden? The bushes will be raring to go when warm weather arrives, making new growth from the stems you have left.
So you've neglected pruning because you're afraid you'll mess up the bushes. Let me list three, and only three, possible problems with performing major pruning of common landscape shrubs in early spring. Please read the warnings but proceed to prune if they don't apply. Early spring is the best time this year to deal with those overgrown bushes.
Warning number one:
Bushes that flower in spring will lose some or all of this year's buds if you prune in winter or very early spring. However, pruning now will benefit flower displays in subsequent years. Good pruning will result in lots of fresh growth on the bush this summer which will then form flower buds for next spring.
Warning number two:
The heavy pruning that I'm discussing here will maim or kill certain bushes. Evergreen shrubs (or young trees) with needle shaped leaves should be pruned with care, making sure to cut only where you can see green growth left behind. They cannot resprout from a bare woody base the way most deciduous bushes and broadleaf evergreens do. If you have juniper, fir, pine or spruce to prune, be sure to read about their specific requirements elsewhere.(see link in Resources below)
Warning number three:
Pruning of larger branches on a shrub may result in dead woody stubs left behind. It's imposssible to locate dormant buds on some old branches, so you won't know exactly where new growth will start. You may have to follow up during the the next few seasons with more pruning to cope with an overabundance of young stems. However, most common landscape shrubs are resilient enough to overcome dead stubs, and any stumps left by early spring cuts will be hidden in a few weeks by new growth.
Many common landscape shrubs respond well to major pruning. Cutting off the actively growing parts on a shrub will stimulate growth from dormant buds, obvious or hidden, on the wood that's left. New growth will come from either the base of the bush or near the cut ends of the branches.
For this work you need hand pruners, longer handled loppers, or a trusty saw. Put on some gloves and protect your arms; you're going to get pretty personal with these bushes. While pruning, you'll probably find dead wood to remove, long sickly branches that have wandered about in search of the sun, and even branches that have grown together in the close quarters.
Choose your cuts with natural shape of the bush in mind
Pruning partway down works well on "bushy" bushes, those with one or just a few stems emerging from the ground. Look for a place where a bud or smaller branch is positioned on the outer side of a large branch. Cut the larger main branch at a slight angle, up near the bud or branch you're leaving to grow. These heading cuts give you a smaller bush with a fairly natural, rounded shape.
Pruning out entire stems works well on bushes that tend to have a lot of cane-like, tall stems coming out of the ground, or that typically grow very long stems in one year. Take the thickest, oldest branches out near the ground where a bush has many stems close together that collect debris. It's safe to remove at least a third of the total number of branches in any given year. Red-twigged and yellow-twigged dogwoods need thinning so they'll keep producing fresh colorful young stems.
Cutting all growth close to the ground at once is an accepted way of coping with some behemoth bushes. This drastic pruning of bushes can be referred to as ‘rejuvenation' or ‘renewal'. Cut all the branches near the ground leaving about a foot of old wood. You'll be surprised at how fast the regrowth will cover those stubs. Here's a partial list of shrubs cited as growing back well after being cut almost to the ground: Abelia, Arizona bells, barberry, beautybush, bird-of-paradise, Buddleia, Caryopteris, (shrubby)dogwood, Euonymus, Forsythia, honeysuckle, Hydrangea, Hypericum, Indian currant, lilac, mallow, myrtle, oleander, rose-of-Sharon, Ruellia, senna, snowberry, Spirea, Texas ranger, weigela, witch hazel, Viburnum.
Here are a few examples of typical overgrown bushes and how to handle them:
Example 1- Foundation plantings are too tall and wide. For curb appeal's sake, and for flowering, you want to reduce the size of the bush while minimizing the bare stems.
Most people are viewing the bush from one or two sides, so you can reach in from the top and start heading back inside branches. Cut far enough below current growth so that you'll still have reduced the bush after it regrows. You can cut a number of inside branches while still leaving the bush looking full from the front. The untrimmed outer stems will still give you this year's display. The cut stems will start filling in the bush this spring at the new size and will make flower buds for next year. In summer or next winter, prune more branches to keep reducing the bush. Heading cuts can be used judiciously to reduce a large azalea over a few years' time. By patiently yet gradually reducing, you stress the bush less and won't lose all the flowers at the same time.
Example 2- A specimen shrub that makes many new stems from the base each year has simply become huge and ungainly. Sometimes long branches on these lay one the ground and root there, gradually turning one bush into a gigantic clump. You can see that some stems are fatter, with more side branches while other newer slender stems have grown too. Removing the older branches will open up the center of the bush for good air circulation and reduce the tendency for debris to build up caught between stems. In addition, you may have to head back (cut the end off of)some remaining stems or you may find the whole thing flopping on the ground. Each "headed back" stem may make several sprouts from near the cut end. Dig up any small bushes formed by rooted branches.
Example 3- Hedges that are lightly sheared sometime each year. This trimming has not kept up with the growth rate of the bush, resulting in one huge hedge. It's now too tall and too wide for a homeowner to easily or safely reach over for clipping, and encroaching on the neighbor's property or your own lawn or walkways. These bushes can add several feet of new growth each summer. To reduce the overall size, you'll have to go well into the bush. Head back to shorter side branches or take it all down to about two feet in height. The bark looks smooth but there are spots along those branches that are ready to sprout new growth when the branch ends are cut off. If cutting entire tops back to few large stubs, follow up this summer and fall by thinning the new growth and shearing to maintain the desired overall height and width.
Your major pruning in late winter may leave you looking at bare stems for now. But in a few weeks when spring springs, new greenery will emerge. Before you know it, you'll have an almost-new bush, in the right size for its spot.
Resources and credits
Begeman, John . College of Agriculture and Life Sciences, the University of Arizona, It's TIme to Rejuvenate Shrubs
Morton Arboretum Horticultural Care Pruning Deciduous Shrubs
Spangneberg, Bruce, Extension Educator, University of Illinois Extension, Prune Shrubs on a Reguilar Basis
Evans, Erv, Consumer Horticulturalist, NC State University, Cooperative Extension, Pruning Narrowleaf Evergreens (Conifers)
Erler, Catriona Tudor. Trees and Shrubs (Better Homes and Gardens Step-By-Step Successful Gardening) Des Moines, Meredith Press, 1995.
Fisher, Kathleen. Taylor's Guide to Shrubs. New York, Houghton Mifflin, 2000.
All photos taken by and property of the author.