Pruning Tips for Healthy Alberta Trees
As my teacher used to say, it's important to prune trees in a way that allows a bird to fly through them when they're fully leafed out. However, when pruning in the hot summers of Alberta, sun scald must also be considered. To prevent lower branches from being exposed to the sun, focus on keeping upper canopy branches that provide shade. Limit pruning to only ⅓ of the overall canopy at a time to avoid causing stress to the tree. If too much is cut back at once, the tree will produce water shoots, which are vertical branches that grow rapidly and weaken the tree. It's best to avoid them by pruning in moderation.
Pruning Trees: Guidelines for Deciduous Varieties
To keep your deciduous trees healthy and looking their best, pruning is crucial. While each genus of tree requires slightly different techniques, there are some general guidelines that apply to most. For trees with an open vase shape, minimal pruning is necessary to maintain their natural beauty. However, for plums, apples, apricots, and pears, it's best to start with the 4 D's: dead, dying, diseased, and direction. The first three are self-explanatory – cut back below the dead, dying, or diseased area. For direction, remove branches that are growing towards the center of the tree, and cut back any crossing or rubbing branches.
Tips for Pruning Trees: Where to Cut and How to Encourage Growth
Are you ready to make your first cut but unsure about the technique? Here's a helpful rule of thumb: cut as close to the collar of the branch as possible, without cutting into it. The collar refers to the slightly thickened ring where the bark meets the branch. Why avoid cutting into the collar? Because it creates a protective barrier that helps the tree fend off pests and diseases. Additionally, when pruning, you should consider the buds. To encourage the tree to grow in a desired direction, cut back to just above an outward-facing bud.
Timing and Sanitization: Key Factors in Pruning Trees
While it's best to prune during specific times of the year, sometimes our schedules don't allow for it. Early spring, after the last hard freeze, is the optimal time for pruning. However, if you're too busy during springtime, fall pruning is a viable option. As long as pruning is done before extreme cold sets in, the risk of die-back is low. One crucial aspect to keep in mind is sanitizing your pruning shears. This is especially important when moving from one tree to another or when dealing with pests or disease. To sanitize your tools, you can use bleach, hydrogen peroxide, spray nine, or even Lysol wipes. We use to use bleach which we cut to 10%. Bleach is hard on tools, clothes and skin. We really like spray 9.
Pruning Apple Trees: Tips and Techniques
Before you start pruning your apple trees, it's important to know whether they are spur or tip bearers. Most apple trees are spur bearing and produce fruit on branches older than three years. On the other hand, tip bearers grow clusters of fruit at or near the tip of the branch. Identify which one you have and adjust your pruning accordingly. Once your tree has reached fruit-bearing size, it's recommended to train it to keep the fruit within reach. Here are some tips for pruning your apple trees:
- Prune when the tree is dormant, from leaf fall to early spring.
- Remove over-long branches to a suitable side shoot.
- Thin fruit spurs to 4-6 inches apart.
- Follow the 4 D's and open the center.
- Choose a leader.
- Over time, prune for renewal by cutting back the oldest branches spurring or otherwise.
If you have the opportunity to train your apple tree from a young age, there are many forms to choose from, such as the bush form with an open-centered crown and 8-10 branches growing from a short main trunk. Other options include the apple swindle bush, the dwarf pyramid, apple cordon, espalier, the apple fan, the apple stepover, and the apple palmette.
Pear Tree Pruning Techniques for Alberta
These fruit tree's are under planted here in the prairies. Pears tend to thrive in sheltered areas, which is why they are often pruned into more technical shapes to compensate for this requirement. Due to their early bloom -and harsh weather, their flower buds have a lower chance of being properly pollinated. Wall-training, espalier, cordon and fans are all popular shapes for a pear tree, while bush and dwarf pyramid forms work well in good sheltered spots.
Pear trees bear fruit on wood that is 2 years or older, but their upright growth habit can become crowded with spur systems if not renewal-pruned. To maintain the shape and restrict growth, summer pruning of highly trained forms (espalier/cordon/fan shape) is needed.
During late winter or early spring, prune the tree to overcome the upright growth and form an open branch structure around a strong central trunk. Establish strong lower branches and remove dominant vigorous shoots on the upper part of the stem back to one bud choosing a leader branch. Tie the leader to a stake if it is not growing straight and vertical. Prune new lateral shoots and branch leaders, cutting to a downward and outward pointing bud to create an open branch structure. Lastly, prune side shoots to 2-3 buds to begin the formation of fruiting spur systems.
For low maintenance pear trees that produce a lot of fruit, we prefer the dwarf pyramid shape, which allows the entire tree to receive ample sun and air. Don't forget to provide light nitrogen fertilization in the spring to ensure your pear tree stays healthy and fruitful.
Pruning Plum Trees: Tips and Techniques
Plums are a delicious fruit that require some specific care when it comes to pruning. There are some awesome plums for Alberta! Although they have complex pollination requirements, the pruning process is slightly less onerous than that for apples and pears. Here are some tips to ensure your plum trees thrive:
- Prune into a bush form, which is recommended as the most productive for fruit growth.
- Plums are not suited for espalier or cordon pruning, so for a technical form that can grow against a fence, pruning into a fan shape is best.
- Plums can be susceptible to pathogens like canker and silver leaf, which can enter through pruning wounds. To prevent this, prune them in the early spring to summer when they can heal quickly.
- You can remove dead wood in the summer when it is easily identifiable.
- Plums fruit at the base of one year old shoots and along the stem of 2 year old and older wood, so young growth is not as vigorously cut back as it is for apples and pears. If you have achieved pollination, you may need to thin the fruit buds 4-6" apart.
To prune a standard plum tree into a bush:
Year 1: Early Spring
- Shorten 3-4 well-spaced laterals by two-thirds to an outward-facing bud.
- Cut the leader back to the highest of the selected laterals.
- Shorten low or narrow-angled laterals to 2 buds.
Year 2: Early Spring
- On each lateral, shorten 2-3 strong sub-laterals by half to a bud that will help produce an open-centered crown.
- Remove any weak, badly placed or narrow-angled shoots.
Year 3: Spring to Early Summer
- Prune horizontally growing or weak branch leaders by a quarter in early spring.
- Cut to a bud where a new branch will grow to fill in gaps in the canopy.
- Remove badly placed vigorous new shoots.
Pruning Apricots: Tips and Techniques
Don't forget apricots in your orchard! When planting apricots, avoid warm and sunny south-facing spots to prevent early bud break from the risk of frost damage. Apricots produce fruit on wood that is two years old or older, as well as at the base of one-year-old growth. Train and prune the tree when buds start to break. If you are pruning the tree into a bush shape, aim for 8-10 branches on a short, clear trunk. Follow the 4'D's pruning until the tree is established and begins fruiting, then prune annually in the early spring. The objective is to maintain an open-centered, healthy and strong bush. Maximize fruiting potential by removing old wood in favor of new growth. Keep the crown as open as possible while still leaving some shading branches. Cut strong lateral branches in half in the spring and trim other laterals to 2-3 buds. If growing in a warm climate the fruit may need thinning, if over burdened by the weight of the fruit the branches will snap.
Burn the branches if there are any signs of pest and disease, otherwise you can chop them up and add them to a compost pile, use them as mulch or wood chips for pathways.
Horticulturist at DNA Gardens