How to Prune Shrubs

Fertilizing, watering and mulching keeps your garden looking great, but many shrubs and bushes also benefit from pruning. Pruning healthy, vigorous shrubs is a bit like getting a haircut because it maintains their shape and good looks. It's even more important if your plants are overgrown, have crossed or tangled branches or when the top growth is dense but there's very little at the base. Timing and technique are everything, so read on to find out how and when to cut.

Shrubs vs. Bushes

Note: "Shrubs" and "bushes" are often used interchangeably, and that's how we'll use them here. But definitions vary. Generally speaking, shrubs are woody plants with one set of roots and multiple woody stems that grow out of or near the ground. They're often shaped or pruned. Bushes can be woody plants with multiple stems or just one stem. They're usually allowed to grow wild.

What Pruning Tools Do I Need?

Some tools are designed for left-handed or right-handed gardeners, so choose the ones that are right for you. For example, if you hold right-handed pruning shears upside down in your left hand, they won't make the best cut.

Pruning shears are for removing branches and stems up to 1-1/2 inches in diameter, and there are two types. Bypass shears have two blades that move past each other to make scissor-like cuts. Anvil-type shears have one blade that cuts when it strikes a metal anvil.

Looping shears are for pruning branches over 1-3/4 inches in diameter. Also sold as scissor or anvil types, they have long handles.

Pruning saws are for branches two or more inches in diameter.

Gardening gloves protect your hands when you're pruning. Longer gloves shield your arms. They come in a variety of sizes, styles and materials. Some are more flexible than others, and some are puncture-resistant or waterproof. Other gardening gear makes pruning easier, like a cart you can use to haul away your cuttings.

Why Should I Prune Shrubs and Bushes?

Pruning helps open up the canopy so more light and air can get in. This helps prevent upper stems from shadowing lower ones and inhibiting their growth. Cutting back stimulates shrubs to form more fruit or flower buds, and flowers are often bigger. Pruning or trimming also maintains the shape and size of shrubs with special forms, like hedges and topiaries.

When to Prune Shrubs and Bushes

Winter is usually the best time to prune, when shrubs are dormant. It's easier to see the branches after the leaves drop and there's less chance of stimulating tender growth that will die in the cold.

Just don't prune spring-blooming shrubs in the winter. If you cut off the buds, you'll lose some or all of your spring flowers. Prune just after the blooms fade. Spring-flowering shrubs include forsythias, Virginia sweetspire, lilacs, quinces, crape myrtles, Rose of Sharon, hardy hibiscus, camellias, azaleas, beauty bushes, viburnums, spireas, deutzias, fothergillas and rhododendrons, among others.

See our fall gardening checklist for more on when to prune.

How to Prune Shrubs and Bushes

Start by removing dead, diseased or damaged wood. Then follow the one-third rule and don't remove more than one-third of the healthy growth on an established shrub at one time. Pruning too much can stress or stunt your plant. Pruning too little can leave weak branches susceptible to breaking or overcrowding, which can restrict sunlight and good air circulation and invite pests or diseases. However, avoid major cuts on newly planted or transplanted shrubs for a season or two so they have time to form strong roots.

Find the stems you want to remove and cut each one about 1/2 inch above a healthy bud. The top of the cut should slant away from the bud so water can drain and the stem and bud won't rot.

Which bud should you choose? Choose one that faces inward or outward, depending on which direction you want the new growth to emerge. Pruning above an inward-facing bud encourages growth toward the center of the shrub. Pruning above an outward facing bud promotes growth away from the center.

Pruning Roses, Hydrangeas, Boxwoods and More

Pruning times and methods vary for different shrubs.

For roses, remove dead and damaged canes at any time. If you live in a cold climate, prune when the rose buds start to swell in spring. In warm climates, prune in early spring before new growth begins. Remove canes or suckers growing below the graft union, if your rose is grafted, as well as canes that rub or cross each other. Cut 1/4 inch above an outward facing bud at a 45-degree angle to open up the plant to more air and sunlight. Cut the stems of faded flowers back to just above a leaf with 5 to 7 leaflets. Knock-Out roses will rebloom even if you remove the faded flowers, or you can prune them in late winter or early spring when the canes put out new shoots. Remove 2/3 of Knock-Out roses every two or three years to rejuvenate them. Prune old, unwanted branches of climbing roses in late winter or early spring.

Hydrangeas can bloom on old or new wood. Bigleaf hydrangeas (lacecaps and mophead varieties), climbing, oakleaf and mountain hydrangeas bloom on old wood. Prune them soon after the flowers fade in summer. Prune smooth hydrangeas in early spring before the buds appear. Panicle hydrangeas, which include white species, limelights and peegees, can be cut back in early spring before the flowers open or after they fade.

Shearing is a type of pruning that removes just the soft, new growth on woody shrubs. Shear boxwoods, spireas and yews with a hedge trimmer or manual shears. Trim as needed during the early part of the growing season, but stop six weeks before the average date of your first frost. Many deciduous shrubs, like burning bushes, lilacs and forsythias, look better when they're selectively pruned, not sheared, so they keep their natural shape.

Fruiting shrubs are pruned at different times by different methods. For example, cut back blueberry bushes by 1/3 every winter and remove old stems to the ground. Do some research to learn how and when to prune the fruiting shrub you're growing.

How to Prune Problem Shrubs

• Correct a lopsided shrub by pruning the shorter side. Cut just above buds that face the direction you want it to grow, so the new growth evens it out. If it's severely lopsided, cut back some old stems from the taller side, too.
  
  
• For a shrub with heavy top growth that looks dead or bare in the center, remove entire branches down to their bases or cut off sections of branches until they intersect with a main stem. This lets more air and light to penetrate the interior of the shrub to encourage new growth.
  
  
• To fix a badly pruned shrub, select a branch with a bud pointing the way you want the new growth to emerge. Cut just above the bud at a 45-degree angle.
  
  
• For woody, tangled shrubs or shrubs with crossed branches, plan to prune over a three-year period. In the first year, start at the base and remove the undesirable center branches as well as any dead, diseased or injured wood. Don't take out more than 1/3 of the shrub's total growth. In the second year, remove another 1/3 of old wood. In year three, take out another 1/3. Again, don't remove more than 1/3 of all the growth at one time. New growth should appear every year until entire shrub is rejuvenated with healthy, new growth.
  
  
• To improve the appearance of flowering evergreens like rhododendrons, mountain laurels and other broad-leafed evergreens that have leggy, lower stems, pinch off the end buds, also called the terminal buds, on new branches. (Don't take off the bigger, fatter buds at the ends of the branches. Those are flower buds, so you won't get any blooms if you remove them.) Taking off the end buds will stimulate dormant buds growing further down on the plant to produce new side branches.

Pruning Tips

• Sharpen your tools as needed to make clean cuts that won't injure plant tissues.
  
  
• To lessen the chance of spreading diseases, clean your tools before use and between plants. Use a commercial product made for this purpose, mix one part of 10% household bleach to nine parts water or use 70% alcohol. Rinse your tools thoroughly, dry them and oil them.
  
  
• Sometimes you need to hard prune, which means breaking the "prune by no more than 1/3" rule. To rejuvenate badly neglected or overgrown shrubs, cut them to four to six inches above the ground in late winter or prior to new spring growth. This will stress them, so hard prune no more than once every three to five years.
  
  
• Don't apply a sealer or pruning paint after pruning. The cuts will heal naturally.
  
  
• Avoid cutting too close to a bud, which can injure it. Don't cut too far away or you'll leave an unsightly stub that may not heal.
  
  
• Keep your cuts at a 45 degree angle to minimize the surface area that could be exposed to disease organisms and to help prevent decay.
  
  
• Be safe. Call a professional if you're dealing with large, heavy or potentially dangerous branches.
  
  
• Reduce the amount of pruning you have to do by planting shrubs that grow to the height and width you want.