By Dave Zeldon and Ely Schweyer
This is a question we hear daily during the spring, summer and, especially, the fall. Unfortunately, many homeowners do not see any adverse changes occurring in their trees until they look dead, or nearly so.
You Might Not Need to Panic Yet
The discolouration and dropping of evergreen needles are a natural phenomenon and the main cause of needle loss in the wild. Evergreen needles, as the name implies, survive for a lengthy period, and in fact usually have a life span of five to seven years on healthy trees, however, they must be shed. The needles first start to die in the central and lower part of the tree, and this change progresses upward over time. You will see spruce trees naturally lose needles as they get older.
Age is an important factor here in causing needle loss and branch death, however, in landscape plantings of coniferous evergreen trees, pests and disease are likely the major cause of needle loss and dying branches. If there is a sudden fall of a very large number of brown needles and leaves, this signals to us that there is something drastically wrong!
This can happen as early as a year or two after a tree is planted. This is especially true in Haldimand and Eastern Norfolk County where heavy clay soils predominate. Spruce trees, for example, do not grow well on clay soils.
When You DO Need to Worry
Here are some of the more common problems, apart from natural aging that afflict spruce trees, the probable causes and ways of treating the problem.
☝️Unfortunately, these majestic trees, the most popular evergreen planted on our residential properties, incur many other pest and disease problems not dealt with here.
Symptom: Rusty brown needles that eventually fall.
Likely causes:
1. Internal fungus disease (called Cytospora or white blister canker). This creates cracks in the bark causing resin to drip and leave grey-white dripping streaks on the bark. The fungus also causes open wounds or blisters on tops of branches. These wounds can be greyish white or greyish blue in colour, eventually turning brown and black.
2. Feeding by spider mites which leave fine, poorly formed webs in the needles, especially near the ends of the twigs.
Best treatments:
1. Properly aerate and fertilize tree out to a distance of half its height in all directions, where possible.
2. Pressure wash thoroughly once a month with water only, all needles and branches as high as possible on the tree. Water pressure dislodges spider mites.
Symptom: Chewed up ends of twigs in June.
Likely cause:
Spruce bud worms which develop in the needle cluster that arises from a bud.
Best treatment:
Spray the biological pesticide, BTK (eg. Dipel), onto the entire tree when feeding is first noticed in early spring, to kill the young caterpillars.
Symptom: Black sooty mold covering twigs and needles.
Likely causes:
1. Spruce bud scales, ball-shaped insects, initially light brown in colour but eventually turning black. Often two to five scale balls cluster in one location on the twig; honey dew excretions from scales become infected with sooty mold.
2. An overhanging shade tree such as oak, maple or elm may have heavily infested leaves with aphids whose honey dew secretions become infected with sooty mold.
Best treatment:
1. Pressure wash tree using water only to dislodge young scales (called nymphs) in May and early June while they are in the crawling stage. Scale nymphs fall to the ground where they cease to be a threat to the tree.
2. Spray shade tree in early spring with insecticidal soap to control aphids. The problems of other coniferous evergreens such as pines, firs, cedars and junipers can usually be treated with correct diagnosis, though some diseases are lethal.
We hope these help you troubleshoot common issues often found in evergreen trees! For more information - and evergreens – visit Eising Greenhouse and Garden Centre! 🌲
Pruning is an essential part of gardening. Essential, but a little intimidating at first because it’s a broad subject. That said, there are some basic rules that apply to most trees and shrubs that will get you started.
There are a number of reasons to prune; the most obvious is for safety, to keep a branch from doing damage or harm by falling or rubbing against something like a building or another tree. Other important reasons include:
- Removing dead, diseased or damaged wood
- Shaping to make a plant bushier, reduce the size and bulk, or slow down growth
- Thinning to increase light penetration and airflow and reduce the possibility of disease
- Rejuvenation to encourage growth, blooming and fruit
Correctly pruning trees and shrubs can help with everything listed above and, most importantly, help maintain the health of your plants. Proper techniques and timing ensure the best results.
The Right Tools
You may need fewer tools to prune than you think!
Secateurs or hand pruners work well on smaller branches.
Loppers or lopping shears have longer handles for more leverage and are ideal for medium-sized branches.
A pruning saw works best for larger branches.
Electric or manual hedge shears are best for cutting a tidy wall of foliage like hedges and shaped evergreens.
The key with garden tools is to make sure they’re sharp and sterile. This can prevent the spread of disease. Clean tool blades with rubbing alcohol after trimming each branch.
When to Prune
Pruning timing requires some research as it depends on the species of the plant and the result you’re aiming to achieve. For example, some trees may be best pruned in the winter while they’re dormant and buds have not yet appeared. To shape a tree, it’s easier to prune before the leaves have formed so that all of the branches can clearly be seen. Pruning early in the gardening season will invigorate the tree. Conversely, pruning after the tree has formed leaves in June will tend to slow down growth.
When pruning flowering trees and bushes, there are other timing considerations. Some ornamentals bloom on branches that grew the previous year. Pruning those branches too early will result in fewer or no blooms. For these plants, it’s best to wait until after they have bloomed.
If you’re unsure about pruning timing for your tree or shrub, this is a fairly comprehensive list to use as a guide. We have also linked other resources below this article.
In general, late fall or early winter is not the time to prune any plant as it encourages new growth, which may be damaged by colder weather.
Pruning Techniques
While some trees may require specific care (pines, for example), here are the basic techniques for pruning trees and shrubs. It’s a good idea to know these basics before you head out to begin cutting branches.
Examine the branch, buds and shoots before cutting. Cutting above a bud facing away from the trunk of the tree will have the branch continue to grow in that direction.
Cut on a 45° angle just above a bud whenever possible. Keep your cut above the lowest bud (the bud closest to the trunk), or the branch will die back.
Before removing a large branch, cut ⅔ off the end of the length to reduce the weight. Once the bulk of the branch has been removed, then cut the rest of the branch away from the trunk by cutting close to, but not into, the “collar” of the branch where it meets the trunk of the tree.
Now You’re Ready to Begin Cutting!
Now that you know the techniques for pruning, where do you begin? Here’s a logical set of steps to follow:
1 - Remove any dead or diseased wood
2 - Remove any branches that are crossing and rubbing together. For a shrub that’s too crowded, remove the thickest branches down to the ground first
3 - Remove water sprouts
4 - Stand back and observe the shape of the tree. If anything is not pleasing about the look (lopsided growth or branches growing too close together or at a sharp angle to the trunk, for example), begin removing or trimming back one unsightly branch at a time. Observing the shape between each cut
5 - Remove any suckers or stubs
Follow The ⅓ Rule!
Once you start, pruning can be fun, but be careful not to get too carried away. Trim up to ⅓ off of an established plant (not a newly transplanted tree or shrub) in one growing season - maximum. Cutting off too much can stress the plant and impact its overall health.
Lastly, know that you can always hire a certified arborist if the task is too much or the tree is simply too large!
Other Resources:
- City of Moose Jaw: Pruning Trees
- Landscape Ontario: Pruning Shrubs and Evergreens
- Ontario Government: Pruning Fruit Trees
- University of Georgia: Pruning Ornamental Plants
