Pruning vs Shearing: How to Tell a Crew Knows Plants

It’s a Wednesday in June. A crew is working its way down your street: one person on the mower, one with a pair of gas hedge trimmers. In about ten minutes, every shrub in the front bed next door is a clean, round shape. Then the crew moves to the next house and does the same.

It looks tidy. It also looks exactly like the house after that, and the one after that. The azaleas that were covered in flowers two weeks ago are green balls now, and so is the shrub beside them that has never flowered at all. Is that the job, or is something being lost with every pass of the trimmer?

Look at the cuts, the shapes and the calendar. A crew that prunes makes separate cuts back to a branch or a bud, leaves each plant in its own outline, and cuts different plants at different times of year; a crew that shears runs trimmers over the outside of everything on the same visit.

You don’t need to know plant names to check. Walk your beds after a visit and look for these:

• The cut ends. Pruning cuts end at a fork, a side branch or a bud. Shearing leaves hundreds of short, chopped stems all at the same depth, and in a few weeks a dense fringe of new shoots grows from them.
• The leaves. Trimmers cut through leaves as well as stems. A few days later, the cut edges turn brown, and the whole outside of the shrub carries a thin brown line. Pruning cuts go between leaves, so there’s nothing left half-cut.
• The shapes. If every shrub in the bed is a ball, a box or a dome, whatever it was meant to be, the shape came from the tool, not from the plant.
• The inside. Push the outer branches of a shrub apart. Green leaves inside mean light is getting in. Bare brown stems behind a green shell mean years of shearing.
• The calendar. Pruning work changes through the year, because plants flower and grow on different schedules. The same cut on every shrub, every visit, means nobody is planning around the plants.
• The flowers. A shrub that flowered well once and now puts out a handful of blooms has usually been cut at the wrong time.

None of this proves anyone did something wrong on purpose. Shearing is fast, and it looks neat the day it’s done. It just isn’t planned around each plant, and the June crew on your street is a good example: ten minutes, one tool, every shrub the same.

Most shouldn’t. Shearing suits formal hedges and the occasional plant grown as a clipped shape on purpose; for most flowering shrubs and small trees, years of shearing costs the flowers and leaves the plant bare inside.

The bare inside is the part nobody sees until it’s advanced. When a shrub is clipped into a ball or a box for years, the outer layer thickens into a shell. That shell blocks the sunlight and air the inner growth needs, so the inside stops growing leaves. From the street the shrub looks full. From up close it’s a green crust around an empty middle, and it has to be clipped again every season to hold a shape it was never meant to have.

Clipped shapes aren’t wrong in themselves. A formal hedge is meant to be sheared, and a pair of clipped shapes by a front door can be exactly what a design calls for. The difference is whether someone chose it for that plant. A good hedge is usually trimmed a little narrower at the top than at the base, so light still reaches the lower branches and the bottom doesn’t go bare.

What goes wrong is shearing by default: the azaleas, the flowering shrub beside them and the small tree at the corner of the house all getting the same haircut because the trimmer was already running.

Each plant has its own right time and its own right cut. We schedule pruning by plant type, so each species is cut at the right time of year. Here’s what that looks like on some plants common in Greater Seattle yards.

Rhododendrons and azaleas. They set next year’s flower buds in the months after they bloom. Pruned soon after flowering, they keep those buds. Sheared in late summer or fall, they lose them, and the next spring is mostly green. Those azaleas next door, clipped two weeks after they flowered, got lucky on timing. The same cut in September would have taken next year’s flowers with it.

Camellias (Camellia japonica). They flower from late winter into spring and set next year’s buds over the summer. Pruned right after flowering, with cuts back to a branch, they keep their shape and their buds. Sheared later in the year, they lose both, and the big glossy leaves they’re grown for end up with brown, cut edges.

Lilacs. They flower on last year’s wood and set next spring’s buds soon after they bloom. The right time is just after flowering: spent flower clusters come off, and on an older lilac a few of the oldest stems are taken out at the base so younger ones replace them. Sheared in fall or winter, a lilac mostly skips the next spring.

Gardenias. They’re grown here in sheltered spots, and they flower in summer. Light pruning belongs just after flowering ends. Cut later, into fall, the next year’s buds go with it.

Bigleaf hydrangeas. Most flower on last year’s stems. Cut to the ground in fall, they grow back leafy and flower poorly the next summer. Properly pruned, the spent flower heads come off down to a pair of healthy buds, and a few of the oldest stems are taken out at the base.

Japanese maples. A well-pruned maple is thinned, so you can see through the canopy and the branches spread in layers. Cut back to a dome instead, it turns into a mushroom that needs cutting every season to keep the shape. Small trees like these are specialty pruning, which we come back to below.

Formal hedges. The one place shearing belongs: straight sides, a flat or rounded top, and the top kept slightly narrower than the base.

For the timing of each of these, and many more, see our guide to when to prune in the Pacific Northwest.

It keeps light and air moving through the plant, so the inside keeps its leaves and the shrub holds its shape without being clipped every visit. It also takes out dead, damaged and crossing branches and leaves the flower buds where they are.

Air matters more here than in drier places. From fall to spring our shrubs stay wet, and a dense, clipped shrub stays wet the longest in the middle, where no air moves. Opening a plant up lets it dry out between rains.

Pruning also changes how often a plant needs cutting at all. A shrub that grows in its own shape needs a few chosen cuts in its season. A shrub forced into a ball pushes out a fringe of new shoots after every shearing, which is why it needs the trimmer again three weeks later.

And then there are the flowers. The whole reason many of these shrubs are in a garden is the three weeks in spring or summer when they bloom. Pruning at the right time is the difference between a rhododendron that disappears under flowers and one that puts out a dozen.

On regular maintenance visits, routine pruning covers the common shrubs that have already been pruned properly. That’s the everyday work: a few cuts in the right season, on plants that are already in good shape. Every property gets its own annual calendar of seasonal work, so each task arrives when it’s due.

Some pruning takes more than a regular visit. Specialty pruning covers small trees, large shrubs, specialty species and restructuring pruning. It’s an Enhancement, quoted in writing, and our enhancements or maintenance manager advises on the specifics for each plant. It’s available with or without a maintenance contract in our full-service cities: Kirkland, Woodinville, Redmond, Bellevue, Edmonds and the cities around them.

Restructuring pruning is how a sheared shrub comes back to its natural shape, and it isn’t a one-season job. It’s done in winter and staged over a few years. The first winter opens the shrub up, and it looks sparse for a while, because you’re seeing the bare inside the shell used to hide. Later winters shape it as it regrows from the inside.

Restructuring isn’t always the right call. If a shrub is mature and sick, replacing it is often more sensible than spending years bringing it back, and that’s a conversation to have before any cutting starts.

The crew with the hedge trimmers comes down the street again. Next door, the shrubs go back to being balls.

Your front bed looks different. The azaleas were pruned right after they flowered, so their buds for next spring are already set. The hydrangea still has last year’s stems, and it’s about to bloom on them. The maple at the corner is thinned, and you can see the sky through it. The hedge along the sidewalk is sheared, straight and slightly narrower at the top, because that one is supposed to be.

If some of your shrubs need more than routine care, see what specialty pruning includes on our landscape enhancements page.