Keeping hedges, privacy screens and topiary full and healthy comes down to a few habits: the right shape, the right timing and the right tools. This post covers those habits, how often to trim a hedge in the Sacramento climate, and what to do when a hedge has gone bare or gotten away from you.
Key Points
- Keep every hedge slightly wider at the base than at the top so the lower branches get light.
- Do the main shearing in late spring after the first flush of growth, with touch-ups through summer.
- Open small windows into a dense hedge once a year so the interior doesn't go bare.
- Large-leaved hedges look better cut stem by stem with hand pruners than sheared.
- Many conifer screens will not regrow from bare wood, so they can't be cut back hard.
Why Hedges Go Bare at the Bottom
The most common reason a hedge goes bare at the bottom is its shape. When a hedge is sheared straight up and down, or wider at the top than the bottom, the upper growth shades the lower branches. Those shaded leaves drop, and the base turns into a row of bare stems.
The fix is simple: keep the hedge slightly wider at the base than at the top. A gentle taper on both sides lets sunlight reach the lower foliage, so the hedge stays leafy all the way to the ground. The top can be flat or softly rounded, but it should always be the narrowest part. This matters even more on the shady side of a hedge, where the lower branches already get less light.
Other causes are worth ruling out too. Sprinklers that spray the foliage but never soak the roots, a lawn mower or string trimmer nicking the lower stems, and a nearby tree that has grown to shade the hedge can all thin out the base. Fixing the shape won't help much if one of these is the real problem.
How Often Should You Trim a Hedge
Shearing works best on fresh growth. Most hedges put out a strong flush in spring, and the first shearing of the year is best done once that flush has grown out, cutting back most of the new growth while leaving a little each time. Leaving a small amount of new growth lets the hedge fill in gradually instead of being cut back to the same woody surface over and over.
- Main shearing: late spring, after the first flush of growth.
- Touch-ups: through summer as needed, usually when the shape starts to look shaggy. Fast growers need more frequent visits than slow ones.
- Flowering hedges: shear right after the bloom so you don't cut off next season's flowers.
- Hot spells: avoid heavy shearing during the hottest weeks of a Sacramento summer, when freshly exposed inner leaves can sunburn.
- Late fall: skip heavy shearing, which can push tender new growth that a winter frost may damage.
Before you start in spring, look carefully for bird nests. Active nests of most wild birds are protected by law, so if you find one, trim around it or wait until the young have left. For a month-by-month view of the rest of your yard, see our seasonal tree care calendar for the Sacramento Valley.
Shears or Hand Pruners
Shears are the right tool for small-leaved hedges like boxwood, privet and podocarpus, where the cut leaves disappear into the surface. On large-leaved plants such as laurel, shearing slices leaves in half, and the cut edges turn brown and ragged. Those hedges look far better when you shorten individual stems with hand pruners, cutting just above a leaf inside the outer surface so the cut is hidden.
Whichever tool you use, keep it sharp and clean. Dull blades crush and tear the stems, which leaves brown edges and a ragged look.
A Step-by-Step Hedge Trim
- Run a string line between two stakes at the height you want, so the top comes out level.
- Start at the bottom of each side and work upward, angling the face so the base stays wider than the top.
- Leave a little of the new growth each time rather than cutting back to old wood.
- Cut the top last, following the string line.
- Reach inside with hand pruners and remove a few dead or crowded stems.
- Rake out clippings from the base and the inside of the hedge.
Avoiding Bare Interiors
Repeated shearing creates a dense outer shell of leaves. Inside that shell, light barely reaches, so the interior becomes a mass of bare twigs. That is normal to a point, but when the shell gets too thick, the hedge becomes brittle and any damage leaves a bare hole that takes a long time to fill.
A few habits keep the interior healthy:
- Once a year or so, reach into the hedge with hand pruners and remove a few selected stems. This opens small windows that let light and air into the center.
- Don't let the hedge creep outward a little every year. Hold it to a set width so the shell doesn't keep getting thicker.
- Clear out dead leaves and clippings that collect inside, which can hold moisture against the stems.
- Water deeply and less often during the dry months, especially in the clay soils common across the valley, where frequent shallow watering keeps roots near the surface.
Topiary and Clipped Shapes
Globes, cones, spirals and other topiary shapes follow the same rules as a hedge, only more so. Choose a dense, small-leaved plant that sprouts readily from older wood, such as boxwood, privet or podocarpus. Start the shape while the plant is young and build it up gradually with frequent, light clipping rather than a few hard cuts. Keeping the base wider than the top helps here too, even on a sphere or cone. A simple frame or guide can make it easier to hold a clean outline. Learn more about our tree shaping service.
In a hot valley yard, give potted topiary some afternoon shade and check the soil often in summer, since containers dry out much faster than the ground. If you're curious where these clipped forms came from and how they compare with espalier and cloud pruning, read our guide to pollarding, espalier and other classic shaping styles.
Recovering an Overgrown Hedge
If a hedge has grown far too tall and wide, or has gone bare at the bottom, there are two main ways to bring it back. Which one works depends on the plant.
Gradual Renovation
Spread the work over two or three years. Cut one side back hard in the first year while leaving the other side full. Once the cut side has regrown, do the other side, then lower the top. The hedge keeps enough foliage to stay vigorous, and you keep some privacy the whole time. This is the safer choice for most hedges.
Hard Cutback
Some tough broadleaf shrubs, privet being a common example, can be cut back hard to low stubs in late winter and will regrow from old wood. It looks drastic for a season, but it can give you a fresh start. Only do this with plants known to recover from it.
When Replacement Makes More Sense
Many conifers used as screens, including junipers, arborvitae and cypress, will not sprout from bare wood. You can trim them lightly within the green foliage, but cutting into the bare zone leaves permanent holes. When a conifer screen has outgrown its space, replacing it is often the better choice. Our tree removal and tree planting services can handle both steps.
When you replant, choose a plant whose natural size is close to the height and width you want, so you're not fighting it every year. Leave enough room between the hedge and a fence or wall for air to move and for someone to trim the back side. If old stumps are in the way, our post on replanting where a tree used to be explains how to prepare the ground.
Get a Free Hedge Estimate
Environmental Tree Service shapes and restores hedges, screens and topiary across the Sacramento area. Call (916) 870-8154 or reach out online for a free estimate.
