The shrubs in your yard have been growing for years, and now that they are reaching their full height, it’s time to trim them back. Pruning is a great way to help keep the plants healthy but also increases air circulation and helps reduce weed growth.
The best time of year to prune shrubs is during the dormant season between late fall/early winter through early spring when there isn’t as much rain or snow melting on the plants.
It’s important to prune those branches you want removed and any dead or diseased branches – this will ensure that new shoots will grow stronger and healthier than before!
What’s the secret of transitioning from a competent gardener to a confident one? Pruning! Though this garden task strikes fear into the hearts of many, it is actually a simple and rewarding process.
All you need to do to master it yourself is to understand a few basic principles behind the why, when, and how of pruning shrubs. Once you implement these ideas and techniques, you’ll see a healthier, more floriferous garden that same season. So let’s get started!
To answer this question, we need to understand what pruning does to a plant physiologically. First, plants are genetically programmed for apical dominance. That’s a botanical term that describes the simple phenomenon that plants always want to grow upward.
Apical dominance is enforced by the terminal bud – the bud at the end of each stem – which produces a constant supply of hormones that keep the buds below it from growing.
When that terminal bud is removed, production of those suppressive hormones ceases, and the lower buds are released. As a result, pruning stimulates a lot of new growth, as multiple buds take over the job that just one single bud was doing previously.
For the gardener, the new growth that results from pruning can accomplish any of the following things, depending on the kind of plant:
- More flowers. This is especially true for plants that flower later in the season, like roses and butterfly bush. Instead of just the terminal bud producing flowers, all of the lower buds will flower as well, multiplying the effect substantially.
- Blooming again later in the season. Reblooming plants like Bloomerang lilac and Bloom-A-Thon azaleas flower more their second time based on how much new growth they put on after their first bloom. A light trim after they’ve finished their spring bloom means a better show come summer!
- Better leaf colour. Many plants with variegated or colourful foliage, like ‘Summer Skies’ butterfly bush or Glow Girl – Birchleaf Spirea, display their best colour and pattern on young growth. Pruning keeps their foliage vivid and showy.
- Brighter stem colour. Plants with attractive stems, like Arctic Fire and Arctic Sun 4dogwood, Plants with attractive stems are the most colourful on stems younger than 3 years old. Pruning encourages the fresh new growth that makes these plants so popular in our gardens.
Pruning may also be used for any of the following purposes:
- First, to neaten the plant’s appearance. Some plants, like ‘Limelight’ hydrangea, keep last year’s flowers on their stems. These can be cut off to keep the new growth and the current season’s flowers looking crisp and clean in spring.
- To control the plant’s height and/or spread. Sometimes, a plant that is really too large for the space will have been planted, and you will want to prune it to stay a manageable size. And some plants, like Sunshine Blue II caryopteris and Black Lace elderberry, are capable of becoming rather large plants, but you may want to use them in a flower bed or a smaller landscape that requires some pruning to keep them tight and compact.
- To rejuvenate an old or overgrown shrub. If you’ve got a very large, very old multi-stemmed shrub on your property, you can give it a new lease on life by cutting it back to short stubs in spring.
- To remove dead, diseased, or damaged wood. For example, sometimes branches of shrubs die from weather, from old age, or are damaged by injury or animals like deer browsing them. Again, pruning is the best way to correct the damage.
Obviously, there are lots of good reasons you might prune a plant, but it’s important to know that pruning is not strictly necessary. No plant dies from a lack of pruning, but plenty die from being pruned improperly! There are plenty of good reasons not to prune a plant:
- If you are happy with a shrub’s size, looks, and performance, there’s no need to prune it.
- It will require little to no regular pruning if it is a dwarf variety, like Lo & Behold butterfly bushes or Show Off Sugar Baby forsythia.
- You should never prune without a reason. Every other decision you’ll make, like when to prune and how much to prune, will come back to the reason you’ve decided to prune in the first place. If you don’t start with a good reason, you won’t be able to determine what to do next!
When is the Best Time to Prune?
Pruning your plant at the proper time is the keystone for success. If you prune a flowering shrub at the wrong time of the year, you will probably miss out on that plant’s blooms for that season.
While this isn’t the end of the world and the plant will recover to flower again the following year, it is definitely disappointing. The risk of missing out on a season’s worth of flowering is probably the main reason most people fear pruning their shrubs. The good news is that pruning shrubs at the wrong time of year almost never harms the plant itself.
To determine when to prune a plant without interrupting its bloom cycle, you need to know if your shrub flowers are on new wood or on old wood. These two terms get thrown around a lot but are rarely explained in simple terms. So here’s what they mean:
- Flowering on new wood means that a plant does not create flower buds until after growth begins in spring. The new growth – or rather, the new wood – the shrub creates that season will be responsible for developing the flower buds that will open later that year. Plants that flower on new wood typically flower later in the growing season. Some examples of plants that flower on new wood include roses, rose of Sharon, panicle hydrangea, and butterfly bush.
- Flowering on old wood means that a plant forms the flower buds for next year’s blooms during the current year. The buds are carried through winter on last year’s growth – the old wood. After these plants bloom, they begin forming the flower buds for the following year. Plants that flower on old wood typically flower early in the growing season. There is, however, one very important exception to this, and that is bigleaf hydrangea like the Cityline series or the Let’s Dance series. These flower in mid to late summer on old wood. Some additional examples of plants that flower on old wood include forsythia, lilac, and weigela.
Spring is the time to do most of your pruning, but the question is, which part of spring? Plants that flower on new wood can be pruned in early spring, just as the new growth begins.
This leaves them plenty of time to recover from pruning and still create flower buds that will bloom that season. The ideal time to do this is after the buds have emerged on the stems but before expanding.
At this point, you can see where the healthy new growth is located, and pruning before the buds leaf out means that the plant doesn’t waste energy on buds you’ll just be cutting off anyway.
Plants that flower on old wood can be pruned immediately after they finish flowering. If you prune before they flower, you’ll remove the flower buds. However, if you wait too long after they’ve finished blooming, they may not have enough time to create flower buds for next year.
We offer a number of reblooming plants. Reblooming plants are capable of flowering on both old and new wood, so the best time to prune them is immediately after their first wave of bloom, which occurs on the old wood.
This allows you to enjoy their spring display and gives them plenty of time to put on new growth for their rebloom. All they require is a light trim after their first bloom to put on new growth, but if you forget to do this, no worries- you’ll still enjoy a great second show!
When you have dead or damaged wood on a shrub, it can be removed any time. Just be absolutely sure it is dead before doing so! It is sometimes tempting, especially in early spring, to look at a plant and assume it is dead or needs to be cut back, but it’s best to put your pruners down and wait to see if any buds emerge.
Wood that is damaged can be removed any time, too, as can growth that hinders free passage on walkways or makes it difficult to access an area of your yard. When it comes to safety, all of the other pruning guidelines are secondary.
Remember, shrubs do not necessarily require pruning to flower and perform well. So if you’re not sure what to do, or you were happy with the plant’s size and performance last year, go ahead and skip the pruning.
Your Guide To Fall Hydrangea Care
Caring for your hydrangea can make all the difference for next year’s blooms. Hydrangeas are strong and can come back from almost anything when given enough time and proper care.
It is important to identify your variety first because some hydrangea varieties do not like being pruned in the fall.
If your garden has hydrangeas, then you need to know that there are two types of hydrangeas. One type produces flower buds on old wood, and the other produces flower buds on new wood.
Stems are called old wood if they have been on the plant since the summer before. New wood is stems that develop in the current season. Most varieties found in gardens are old wood bloomers, including Mophead, Big Leaf, Lacecap, and Oakleaf hydrangeas. Double-check your variety with your local garden centre.
When to Prune
Hydrangeas can grow for years without being pruned, but if they get unruly, overtake an area of the garden or lose their growing capabilities – it is time to trim. But when to prune them?
Prune fall-blooming hydrangeas, or old wood bloomers, after they bloom in the summer. If you prune old wooded hydrangeas in fall, you are cutting off next seasons blooms. Summer blooming hydrangeas, or those that bloom on new wood, are pruned in the fall after they stop blooming.
Hydrangeas are colourful and vibrant in the early season but are hard to preserve after being cut. However, they are easier to care for after they start drying on the bush.
How to Prune
Near the bottom of your plant, you will see thin, wispy, weak growth. Cut those down. They will take up energy that your plant could use for blooms.
Look for any dead stumps on your stems. They will not have grown any new wood or buds out of the original old wood. Cut the dead stumps down to their base to completely remove them. This will allow the new growth underneath to have a chance to succeed.
Dead and old blooms need to be removed to make room for new buds to come through. Cut the flower head off right above the first few leaves to encourage colours for the next summer.
Stand back from the plant and observe its shape. You’ll want to prune the shrub into the shape you prefer, a sphere is the typical style, but you could prune it into any shape you want!
Clean the Debris
Remove any debris that fell off from the base of the plant. In addition, you want to make sure your soil is free of any weeds, leaves and dead flowers.
For the best hydrangea care, feed 2-3 times throughout the growing season, which is from spring until fall. Follow these few steps, and your hydrangeas will be happy and vibrant for years to come.
Plum trees do not require as precise pruning as apples and pears but still benefit from initial training and the thinning of old wood to ensure they produce as much fruit as possible. Plums are pruned in early spring or mid-summer to avoid infection by silver leaf disease.
When to prune plums
Avoid pruning plums in winter, as it increases the risk of infection by silver leaf disease to which plums and other Prunus species are prone. The best time for pruning is usually spring for young trees and mid-summer for established ones.
How to prune plums
There are three commonly used methods of pruning plums: bush, pyramid and fan. Plums trained as cordons are gaining popularity too.
The bush is perhaps the most popular method of training and pruning and creates an open-centred tree with a clear stem of 75cm (2½ft). Its ultimate size will depend on the rootstock it is grown on. Trees grafted onto ‘Pixy’ rootstocks will reach 3m (10ft), ‘St. Julien A’ 3.6-4.5m (13-15ft) and the ‘Brompton’ and ‘Myrobalan B’ 6m (20ft).
The overall aim of pruning is to create an open-centred tree. This begins with the same formative pruning as apples and pears but, importantly, is carried out in early spring.
On established trees, rub out any buds developing on the lower trunk and carefully pull off suckers arising from the rootstock. Pruning is mostly limited to removing crossing, weak, vertical and diseased material. If the plum tree is still crowded, then further thinning can be done in July.
A pyramid plum tree is considerably smaller than a pruned bush, making it practical to net against birds. Plums on ‘St. Julien A’ rootstocks are kept to 2.4m (8ft) and on ‘Pixy’ rootstocks to 1.8m (6ft).
The pruning of a newly planted tree is the same as for apples and pears. Remember: carry out in April, not winter, to avoid silver leaf disease.
After the initial pruning, follow these steps: During the first summer:
- Prune in the third week of July when the young shoots have finished growing. Shorten new branches to 20cm (8in), cutting above a downward or outward-pointing bud
- Cut side branches back to a bud at 15cm (6in)
- Train and tie in the central leader to the stake
In subsequent years:
- During April, shorten the central leader by two-thirds.
- Repeat annually until the tree has reached 2.4m (8ft) on a ‘St. Julien A’ rootstock, or 1.8m (6ft) for ‘Pixy’, after which, shorten the central leader to 2.5cm (1in) or less each May, to keep the tree at the same height
- Vertical shoots at the top that compete with the central leader should be removed in late June.
- In the third week of July, shorten branch leaders to 20cm (8in), pruning to a downward or outward-facing bud in the axil of the leaf. Cut side branches back to a bud at 15cm (6in)
A fan-shaped tree is created by training against a wall or fence with horizontal wires fixed 15cm (6in) (or two brick courses) apart. Trees can be bought as maidens or partly trained. Expect the height and spread of trees on ‘Pixy’ rootstock to be 3m (10ft) high by 2m (6½ft) spread and trees on ‘St. Julian A’ to be 3.6m (12ft) by 2.4m (8ft).
Neglected and overgrown bush trees
Renovating an old, neglected plum tree should be staged over several years. Aim for a well-balanced tree, keeping the centre of the crown free from shoots to allow good light penetration. Trees respond to larger pruning cuts by sending up a mass of new shoots. Where this happens, the shoots will need to be thinned in the summer to leave just one or two.
The tying down of young, flexible branches to the horizontal can reduce excess vigour in large, unruly trees. This technique is known as festooning and is best done in the summer. It can help prevent trees from becoming overgrown and is also effective for pyramid plums.
Ties are left in place until the branch stays naturally at the new position, usually the following spring. Then, attach one end of the tie to the branch tip and the other end to a stake or the trunk.
Plums can be heavy croppers, leading to branches breaking under the weight of fruit, so thinning is important to prevent damage. Branches already broken should be pruned back into undamaged wood, ideally cutting back to a natural fork to avoid leaving stubs.
Bare wood areas can be difficult to remedy on fruit trees. However, here are a few techniques to try:
- In spring, stimulate dormant buds by pruning back to just above the bare section.
- For large branches, before new growth starts in spring, remove a small section of bark from just above a dormant shoot where you want to encourage growth. This technique is known as notching and aims to restrict the flow of suppressive growth hormones from further up the shoot to stimulate growth in the treated bud.