Now that spring has sprung it is important to know how to care for your trees, which, like all plants, require care to grow to become big and sturdy.
Gordon White, Okotoks parks specialist and urban forester, said spring is a good time for people to prune most varieties of trees and shrubs.
One exception is elm trees, which can only be pruned from October 1 to March 31. There is a provincial pruning ban on elm trees between April 1 and September 30 to help prevent Dutch elm disease.
As well, White said maples and birches are the only species that should not be pruned while they are dormant because the sap will drip from the pruning cuts in the spring.
“Prune maples and birches during the summer, while they are in full leaf, and they will not drip sap,” said White.
According to White, spring is a good time to prune out deadwood and look for any sign of disease. He recommends looking for branch dieback and the formation of growths or, more commonly, a canker, which is usually sunken, discoloured and has sloughing bark.
White said to prune below the signs of disease to the visible swelling in a tree that forms at the base of a branch where it is attached to its parent branch or to the tree’s trunk commonly known as a branch collar.
“A tree or shrub is typically at its weakest point when it is leafing out or flowering, so it’s best to prune before that time or wait till after is it full leaf,” he said.
White recommended pruning out all deadwood, but said people should be certain not to prune out too much live wood. He recommends pruning less than one-quarter live wood.
The timing of this will vary from year-to-year, so he recommends people keep an eye on the plant’s stages of development. Spring can be wet and damp but he said to avoid pruning in these conditions because it is a good setting for the spread of diseases. The dormant season in late fall, winter and early spring is the best times for pruning to control diseases, said White.
White said there are proper ways to prune and people should use sharp tools. Trees are a long-term investment that increases in value over time, until they start to decline, he said.
It’s often best to hire a professional, he said.
“I strongly recommend hiring a qualified arborist, said white, preferably an ISA (International Society of Arboriculture) Certified Arborist, to prune your trees, especially if they are too large to reach with a stepladder,” said White.
He said early spring is also a good time to transplant small trees or shrubs that may not be in the right spot in your yard. White said can start this as soon as the ground is thawed and before it has started to leaf out. At this time trees and shrubs are starting to grow roots and this will help it get established in its new location.
White said the most important thing for tree health is using preventative measures. Healthy trees and shrubs are less susceptible to insects and diseases. This means planting in the right location and ensuring plants have adequate moisture and nutrients by adding mulch around the root system.
Dan Blaaberg of Beaver Dam Nursery said in the spring before the trees leaf out, it’s a good time to see if there are any existing diseases or cross branches that should be removed.
“Whether it is fire blight, black knot or pear rust in the junipers, now is a good time to clean it up,” he said.
Blaaberg said when removing diseased branches, clean the pruning equipment between cuts to prevent spreading the disease. He also said not to use any the diseased branches for mulching gardens or composting as the bugs and wind can spread the diseases from these branches to other trees.
