The wet trimming process and dry trimming process both have pros and cons. Some growers prefer trimming the buds when they are freshly cut from the plant while others prefer waiting until the plant is dry. Neither method is right or wrong; it all really comes down to personal preference.
But if you do want to tackle them yourself, have patience and wait until it's dry or has at least stopped raining. You may notice that the job you do in wet weather is not as great as the one you did in the dry weather. What's more, electric hedge trimmers are not safe to operate around moisture.
I don't worry about pruning when the foliage is wet because the risks of disease are well mitigated. But if you are in an area with high disease pressure, the plants are in native soil, and you don't do a lot of proactive disease prevention, it is best to wait until they are dry.
Avoid pruning shrubs in winter that will bloom in spring.
Those buds live through the winter, ready to open in spring. If you prune these plants in winter, you'll be cutting off flower buds. (The saying is that these shrubs “flower on old wood,” meaning on twigs that grew the previous year.)
Rain events, in particular, can aid in the spread of infectious spores, so pruning should be avoided if there is rainfall forecasted.
Moist, humid weather prevents cuts from healing properly and makes it possible for fungal spores and bacteria to set in - resulting in an increased risk of disease and damage to the hedge.
When pruning mature, overgrown shrubs, remove the thickest branches first. Cut them back to the base of the shrub to promote new growth. Hand pruners are useful for smaller branches. Some can cut branches up to an inch in diameter, but long-handled loppers give you leverage to cut branches 1 to 2 inches in diameter.
The 1/3 rule for pruning shrubs refers to the practice of cutting about 1/3 of wood or a branch. This approach is applied to fully established shrubs and small trees. This is done at this stage since the established shrubs and plants are past their transplant shock.
Summer is an excellent time for restorative pruning. Summer pruning tasks may include removing dead, damaged or diseased branches. Many people think of pruning as a winter task, but there are a number of great reasons to prune your trees and shrubs in summer.
Don't cut branches flush against the trunk. Open up a plant with thinning cuts. Don't cut more than one-third of the plant's height in any one season. Cut at the proper time of year — usually late winter or early spring, though there are exceptions.
Birds typically breed between the months of March and August every year, so it is best to avoid working on hedges and trees in these months as birds will most likely be nesting their new hatchlings during this period.
Wet trimming can be easier for new growers like me since it's pretty easy to work your way around the plant snipping off full stems of leaves. The buds and leaves hold a lot of moisture, which is why it's called wet trimming.
Depending on your environment, fruit trees can be pruned when dormant either in the summer, or in the winter a month or two before spring. In general it is a bad idea to prune during rainy weather, as this adds to the chances of fungal issues in your tree.
Wet trimming is easier. It is easier to remove the fan and sugar leaves while they are wet. When those leaves are left to dry, they shrivel up. Easier trimming means it takes less time to trim.
Follow the 1/3 rule
This can mean removing one third of the total height, or one-third of the total number of branches, depending on the type of plant and how severely it needs to be cut back. It's best to err on the side of caution and cut too little than too much.
Never prune when it is damp or wet out. The dampness can encourage bacteria to grow. Make sure to cut between sickly branches and the body of the tree. When taking complete branches off try to get as close to the main stem and cut at the same angle as the branch collar.
Pruning in autumn and winter could potentially damage the plant, as it can unbalance the root to shoot ratio during a period when it is too cold to regrow. The best time to prune is after flowering.
If you have a shrub that blooms in the spring, prune it after the blooms have completely faded. If your shrubs bloom in the summer, do your pruning in late winter or early spring.
Make cuts at a 45-degree angle using the appropriate tool for the branch size. I like to use lopping shears to reach into the bush. Individual branches can be cut back to the main trunk, leaving a 1 to 2-inch stub. If the branch splits into two, you can cut just above the split.
Removing dead or dying branches will not only help to prevent the spread of disease to other parts of the plant, but it will also help the tree or shrub to focus on producing new, healthy growth. Older wood that no longer flowers can also be removed.
The term bush is more often used as an adjective describing how shrubs grow than an actual plant. If multiple shrubs are planted close together, or a shrub grows round instead of straight up, they are considered a bush. Bushes are typically left to grow as nature sees fit unlike the yearly pruning shrubs require.
Best Time for Shrub Pruning
Trim shrubs in the summer as soon as possible after flowering to favor as many of next year's flower buds as possible. The later into the summer pruning is done, the more gentle it should be to preserve as many flower buds as possible.