Knowing how to shape crape myrtle, Japanese maple and the other ornamental trees common around Sacramento starts with knowing what each one wants to look like. This post covers a good shape for crape myrtle, Japanese maple, Chinese pistache, redbud and olive, the best time of year to shape each, and how to recover a tree that was cut the wrong way.
Key Points
- Shape crape myrtles in late winter by thinning, not by cutting every branch back to the same stubs.
- Japanese maples need light, selective thinning in the dormant season and should never be sheared.
- Chinese pistache benefits most from structural shaping while it is young.
- Shape redbuds right after they bloom and olives only in dry weather.
- On any mature tree, cut outside the branch collar and take no more than about a quarter of the live canopy in a season.
How to Shape a Crape Myrtle
Crape myrtles are everywhere in the valley because they love heat and bloom through the summer. They are also the most commonly mistreated tree in town. Cutting every branch back to the same stubby height each winter is a form of topping, and it causes real problems:
- Knobby knuckles form where the cuts are made year after year.
- The tree sends up clusters of long, thin shoots that often bend or flop under the weight of their flowers.
- The smooth, peeling bark, one of the best features of the tree, gets hidden behind a thicket of regrowth.
A well-shaped crape myrtle has a handful of well-spaced trunks that rise in a loose vase shape. To get there, remove suckers from the base, take out branches that cross or grow into the center, and gradually raise the lower side branches to show off the trunks. An open canopy also dries faster after watering and dew, which helps with powdery mildew, a common crape myrtle problem. Late winter, while the tree is dormant, is the best time. Crape myrtles bloom on new growth, so winter shaping doesn't cost you flowers. If a crape myrtle is simply too big for its spot, the answer is a smaller variety, not a yearly hard cut. You'll find more on this tree on our crape myrtle page.
Fixing a Crape Myrtle That Was Topped
If your crape myrtle already has knuckles, it can usually be brought back over a few years. In late winter, choose two or three of the strongest, best-placed shoots growing from each knuckle and remove the rest. Those shoots become the tree's new branches, and each year you thin and space them a little more. In some cases it makes more sense to cut the trunks lower, below the old knuckles, and retrain from there. A professional can tell you which approach suits your tree. Our post on restoring a tree that was topped or neglected explains the general process.
How to Shape a Japanese Maple
Japanese maples are prized for their layered, graceful branching, and good shaping simply reveals it. The work is light and selective: remove dead twigs, branches that cross or rub, and shoots growing back into the center of the tree. Then thin just enough that you can see the structure of the limbs through the leaves. Never shear or top a Japanese maple. It destroys the natural form that makes the tree worth having.
Structural shaping is easiest in the dormant season when the branches are bare and you can see what you are doing. Keep summer work to small touch-ups. Be cautious about opening the canopy too much in a hot Sacramento yard, because the thin bark and delicate leaves of many Japanese maples can scorch in strong afternoon sun.
Work from the inside out with small hand pruners, and step back often to look at the whole tree. Weeping, lace-leaf types need a slightly different eye: the goal is a layered mound where you can glimpse the twisting branches underneath, so thin out stems that pile on top of each other rather than trimming the outside of the mound into a smooth dome.
How to Shape a Chinese Pistache
Chinese pistache is valued here for its tough nature and bright fall color. A mature pistache naturally forms a broad, rounded, umbrella-like crown, but young trees are often gangly and lopsided. That is exactly why early structural shaping pays off: choose a strong central trunk or main leader, select well-spaced scaffold limbs, and remove competing stems before they get large.
On a mature tree, shaping means thinning crowded areas, balancing the canopy and raising low limbs for clearance over walkways and driveways. Winter dormancy is the usual time. Resist the urge to shorten every branch tip to make the crown look rounder faster. Those cuts produce clusters of upright shoots that crowd the canopy. See our Chinese pistache page for more on the species.
Shaping Redbud and Olive Trees
These two need less shaping than a crape myrtle, but timing matters more for both.
Redbud
Redbuds can be grown with a single trunk or several, and both look good. Their weak spot is narrow, tight forks where bark gets pinched between two stems. Those forks can split as the tree grows, so a key part of shaping a young redbud is removing one side of any tight V-shaped fork while it is still small.
Redbuds flower on older wood, including the trunk and main limbs, so the best time for shaping is right after the spring bloom. Pruning in winter works too, but you'll cut off some of the flower buds. Dead or broken branches can come out any time of year.
Olive
Olives, fruiting and fruitless, suit the dry valley summers well. A nicely shaped olive has an open center that shows off its twisting trunks and lets light and air move through the canopy. Thinning cuts that remove whole branches back to their point of origin work far better than shortening everything, which triggers a flush of vertical shoots. Remove suckers from the base and water sprouts from the trunk as they appear.
Shape olives during dry weather. Olive knot, a bacterial disease, spreads into fresh cuts when it rains, so avoid pruning during the wet winter months. If you see rough, knobby galls on the twigs, cut those branches out in dry weather and clean your pruners between cuts so you don't carry the bacteria to healthy wood.
Shaping a Young Ornamental Tree Step by Step
Many shaping problems on mature ornamental trees started when the tree was young. A few minutes of careful work in the first several years sets up a framework that looks good and holds together for decades. The same order of work applies to almost any of the trees above.
- Remove the obvious first: dead, broken and diseased twigs, plus suckers from the base.
- Decide on the trunk form: one main leader, or a few well-spaced trunks for multi-stem trees like crape myrtle and redbud.
- Fix tight forks: where two stems of similar size grow in a narrow V, remove or shorten one while it is still small.
- Space the main limbs: keep branches that are spread around the trunk and up its length, and remove ones that crowd each other.
- Take out crossing and inward growth: branches that rub or head back into the center of the tree.
- Step back and stop early: look at the tree from several sides, and leave further changes for next year rather than removing too much now.
Our post on structural pruning for young trees goes deeper on setting up a strong framework.
Shaping Timing at a Glance
- Crape myrtle: late winter, while dormant.
- Japanese maple: dormant season for structure, light touch-ups in summer.
- Chinese pistache: winter dormancy.
- Redbud: right after spring flowering.
- Olive: dry weather, away from winter rains.
Whatever the species, the same basic rules apply: cut just outside the branch collar, avoid flush cuts and stubs, and take no more than about a quarter of the live canopy in one season on a mature tree. For the rest of your yard, see our guide to when to prune common Sacramento-area trees.
Schedule Your Ornamental Tree Shaping
Environmental Tree Service shapes ornamental trees across Sacramento and nearby cities, and estimates are free. Call (916) 870-8154 or contact us online.
