An important part of tree pruning and maintenance is dealing with suckers and water sprouts. Especially for many modern grafted plant selections, removing these fast-growing plant parts increases plant vigor and health, while keeping your plants neat and tidy, and in their natural form!
Read on to learn about the causes, prevention, and removal of these common plant occurrences.
What are Tree Suckers?
Suckers are stems or new shoots growing up from the ground or around the base of a tree. These can out-compete or crowd the main growth of a plant quickly and usually signify your plant is in distress one way or another. Other plants naturally sucker and for a more aesthetic look, or to control their spread, removing them is preferred.
Trees that tend to sucker are thicket and colony-forming, such as some native American Hazelnuts, Wild Plums, Hawthorn species, and a few Crabapples, native Redbud, Birch, Flowering Dogwood trees, and Pawpaw, plus a few others. However, any tree in distress will begin to sucker in an effort to stay alive by pushing out lots of growth fast from the root area.
Unless it is a natural feature of your tree, suckers literally suck the life out of your tree by consuming large amounts of water, nutrients, and energy. Reducing vigor, fruiting, and causing irregular growth.
What Causes Suckering?
There can be many factors that result in a tree that normally doesn’t sucker to produce these growths.
- Your plant is stressed or the roots were damaged
- Planting too deep in the ground
- Pruned too much too fast
- Disease or insect pressure
- Failure of the graft or the grafted portion has died or is stressed
Sometimes grafted trees, both those grafted at the top and closer to the roots also sucker when the desirable graft has died or is stressed, causing the rootstock it’s grafted onto to begin growing in a last-ditch effort to survive.
Growing fast and usually away from the main plant, suckers can leech energy and nutrients from your plant and turn the area into a tangled thicket.
How to Control Tree Suckers
Similar to pruning, removing suckers involves cutting away errant growth from the base of your plant, like many thicket-forming style plants tend to have. This is best done in the early spring before your plant has broken dormancy or any time you notice a sucker forming.
Cleanly nip off the suckers as close to the trunk/roots as possible without cutting into the collar or the trunk's bark (which can lead to disease or insects gaining access into the plant's tissues). Other ways to remove suckers may involve getting out a sharp spade and digging down carefully to remove them where they sprout from the roots.
Sometimes these suckers can have their own root systems and are essentially runners - and that means free plants! Sever them from the parent plant and relocate them elsewhere in your landscape with as much of their own root system as possible! This is especially desirable as long as it is not a grafted variety. In those cases, you are transplanting the rootstocks suckers.
Grafted Trees and Suckers
Your 'own-root' trees that die back or are severely cut back, can regrow anew from their roots and suckers, it just takes some time. Unfortunately, if certain kinds of grafted trees develop suckers from the rootstock, it’s a sign of distress. On grafted or budded tree selections, if the sprouts originate below that graft union, the sucker that forms will be from the rootstock and are not the desired cultivar.
Sometimes you will see a Crabapple tree that blooms with both white flowers and pink flowers. This happens because suckers have formed from the rootstock and were allowed to grow alongside the main trunk unnoticed. Those suckers need to be removed as soon as it is noticed.
To determine if the graft is alive or dead, perform a ‘Scratch Test’ on the graft by scraping away a very small amount of bark to reveal the cambium layer beneath. If it's green, then remove the suckers from the rootstock carefully and baby along your plant while it waits for the right conditions to emerge from dormancy. If there is no green beneath the bark, and it's dried up, it’s tan, or brown, then unfortunately something happened to the grafted plant and only the rootstock is alive. This means you will have whatever species the rootstock is and not the desired plant's growth, flowers, or fruit.
What are Tree Water Sprouts?
Also known as water sprouts, these are very fast-growing, nearly perfectly straight stems that sprout perpendicular to the ground. Forming on the branches and limbs of a tree. Sprouting up several feet in a season, these form after similar occurrences as suckers and can have an equally sapping effect on the energy and vigor of a plant.
Often sprouting from dormant buds along the limbs or trunks of the tree, they are easily broken away from the stems and can tear or cause other damage with ease. The leaves on water sprout branching can be different from the more mature leaves on the rest of the plant as well. Water sprouts also crowd the canopy, making it look unkempt, and reducing air circulation and sunlight penetration into the interior of the canopy - leading to an increase in pest or disease issues.
Not only do water sprouts sap energy, but these sprouts also don’t fruit or flower very well - if at all, and reduce a tree's ability to flower and fruit effectively. The weakness of water sprouts leads to damage during windy, stormy conditions and during heavy snow.
What Causes Water Sprouts?
Some plants are a bit more prone to forming water sprouts, while others only sprout water sprouts when stressed. Originally called water sprouts, or water growth, due to the sprouts forming after extended periods of heavy rain, water sprouts also occur during drought, soil compaction, and other stresses.
How to Remove Tree Water Sprouts
Early spring is also the best time to remove water sprouts from your tree, just before deciduous plants break dormancy, the entire canopy is easily accessed and reached without the clutter of foliage in the way. However, it is also best to remove water sprouts as soon as they are noticed - even during the growing season so you don't end up with large amounts of pruning to be done at any one time. Get them when they are small, it is so much easier. As with renewal pruning and shaping your plant, remove no more than ⅓ of the plant at any time each year.
Like pruning for suckers, remove water sprouts flush with the limb they’re growing perpendicularly from with clean, sharp pruners. Being careful not to cut into the collar or into the bark of the tree.
For many types of trees, removing suckers and water sprouts is a normal, year-to-year part of pruning maintenance. Unfortunately, once suckers begin to form on a tree, it may now be a regular occurrence.
How Do You Prevent Tree Suckers and Water Sprouts?
The first line of defense is a good offense. Keep your tree happy and healthy so it is stress-free:
- When planting, it's important to only plant as deep as the roots already are in their nursery container. On bareroot, look for the soil line left from where it was previously planted, or look for a change in bark textured between the upper trunk and the roots.
- Because planting too deep is a very common occurrence and reason for suckers to form, and stress your plant into producing water sprouts, please do pay attention when installing any new tree or shrub!
- Regular slow-release fertilizers if needed, and water during times of drought and extreme heat are essential to bolster your plant's health so it can fight off insects and diseases on its own and reduce stress.
- Provide a 3-4 inch layer of arborist mulch as topdressing to insulate the roots, hold in moisture, and enrich the soil as it decomposes.
- Never prune more than ⅓ of your plant off or remove more than ⅓ when renewal pruning
- Avoid topping or ‘lolly-popping’ trees
- Avoid piling mulch up around the trunk of the tree, allowing water and insects free reign against the bark.
Happy Healthy Plants!
Keep your trees happier and healthier with a mindful approach to pruning away these wild hairs of the plant world! Even the best cared-for plants can develop these issues, so it’s important to survey your woody and deciduous trees each year in the early spring while they are still dormant and the branching framework is easily visible.
You’ll keep the energy coming from the roots pushing into your plant and its flowers and fruit instead of the growth that is sapping energy from the plant! Giving you years of enjoyment for just a bit of maintenance!
Happy Planting!
