Camellias do not require pruning, however respond very well to it. If desired, you can prune a camellia to maintain fullness or a desired shape, to form a small specimen tree that makes an ideal focal point in the landscape, or to rejuvinate an old plant that has become spindly. You'll find some basic guidelines for each of these camellia pruning techniques below.
Pruning Younger Camellia Shrubs
When to Prune
For younger plants (1 to 10 years old) it is best to do some shaping just after the blooms have faded (spring or early winter, depending on the variety). Sasanqua varieties bloom during the fall into early winter, while the Japonica varieties bloom in late winter through early spring. Just keep in mind that if you prune just after the camellia finishes blooming, you won't remove the next year’s flower buds!
How to Prune
Many camellia varieties need pruning to keep a nice shape. Pruning also helps to stimulate new growth. On younger camellias, you'll want to use a sharp pair of bypass hand pruners to cut back scraggly or drooping branches that formed during the previous growing season. I usually trim these long branches back to a point a few inches outside the main form of the shrub. This way, new branches will emerge from the branch buds just below where you make your cut.
Thinning the center of the shrub can also be helpful to improve air circulation and can help to prevent sooty mold caused by aphids. Removing secondary branches emanating from within the framework of the plant and snipping off nonproductive interior branches creates an open branching framework. Just make sure you don't remove a branch that would spoil the shape of the plant!
NOTE: Cease any pruning of camellias after July and you are almost guaranteed not to effect the next season's bloomage.
Tree-Forming A Camellia
Whether young or old, a camellia variety that grows tall enough can be pruned to form an attractive small tree. Tree-forming may also help to rejuvinate older camellias. The goal in tree-forming is to form a nice canopy of branches and foliage on top of what is usually one to several exposed lower trunks.
When to Prune for Tree Forming
Regardless of the type camellia, this pruning technique should be done in late winter.
How to Prune for Tree Forming
Before removing any branches, study the plant to decide how many trunks you'll want. If you intend to remove any trunks these will need to be cut or sawed off as close the ground or base of the plant as possible. Before removing any main trunks make sure that doing so will not spoil the shape of the canopy.
After you've selected and removed any unwanted trunks, you can start "limbing up" the plant to form the tree. Start by removing a few of the lowest branches on the main trunks. Be careful not to remove a branch that would spoil the shape of the canopy. Step back after removing each branch to take a look at the effect. Continue removing lower branches upward to a point that is satisfying in appearance.
NOTE: The use of pruning sealer is not necessary though you may use it if you want.
Rejuvination Pruning of a Camellia
If your older Camellia has become overgrown, spindly and weak, rejuvination pruning may be necessary.
When to Rejuvination Prune
Rejuvination pruning should be done in late winter while the camellia is still dormant.
How to Rejuvination Prune
An old camellia can be cut back as far as necessary, even to a stump, and will regenerate into a beautiful plant within a relatively short period of time. Of course, you don't have to prune all the way back to short stumps. I often remove at least 1/2 to 2/3 of the height and width of the plant, keeping a rounded form verses a flat top. Pruning older camellias will most likely require the use of a hand saw.