Watersprouts appear as strange, out of character growth from the older branches of a tree (usually) or large shrub. They tend to grow fast, often uncannily vertically, sometimes in clusters at a single point. Removing them is a typical no-brainer pruning task.
You can think of watersprouts as suckers that come from above ground instead of below ground. If this makes sense to you, you can absolutely understand and treat them in this way.
What Are Watersprouts?
Watersprouts are the growth resulting from buds on the surface of or (commonly) buried in the old wood of a plant. The growth is very thin relative to the parent branch and the joint between the sprout and branch is weak. Like a sucker, the sprout wood is juvenile and fast-growing, fed on ample water and nutrients from the large parent wood.
Though they happen naturally, and rather frequently in some species, watersprouts are generally regarded as something going wrong in the plant. They originate from old buds often buried in the wood and invisible. In nature, they are perhaps a way for a damaged plant to recover, but in the garden, they are considered to be a waste of energy put towards weak, out of place growth.
As tender, young growth, watersprouts are believed to be a vulnerable access point for pathogen attacks. Certainly in an orchard and other situations of highly regulated growing shapes they are a nuisance, breaking the good architecture of the plant with weak wood that won’t bear fruit.
In most cases, though, water sprouts are just an aesthetic problem. We remove them because the little twigs squirting from the side of a majestic trunk or branch look silly to us.
Recognizing a Watersprout
Thin growth, especially clusters of thin growth, from places where there did not seem to be a node or bud are suckers.
They don’t occur on younger wood, where the buds are at the surface and strongly under control of the hormones of the healthy growing tip that keep other buds dormant.
Watersprouts, like suckers, often bolt for the sun. When protruding from the top of a branch, they are strangely upright, fast-lengthening stems that break the character of a good scaffold branch. When they come from the side of a plant, rather than stretch out they will sometimes curl upright.
Like suckers, plants produce more water sprouts if under stress or badly pruned. To reduce watersprouts you should just keep up with the normal good pruning you always strive for. Factors related and unrelated to pruning that can cause watersprouts include:
- Making a heading cut on a large branch rather than cutting it back to its base is almost guaranteed to produce watersprouts near its tip. Cutting a major branch back to its base may still cause some sprouting around the wound.
- Exceeding the 1/3 rule of pruning makes watersprouts more likely.
- Major die back, which is essentially the same as too-hard pruning but not your fault. Drought or winter kill are examples I have both seen cause watersprouting. A wound to a trunk may cause sprouting around the wound.
Most of the time, you’ll be removing watersprouts as waste. There is no skill to it; just cut them off any convenient way. For first-year sprouts, it is not important to make a clean cut at the base with an appropriate tool because the wounds from removing these are minor and will heal quickly. If you catch the shoots very early, you can even rub them out with a thumb. In a pinch, I’ve even sloppily wielded a shovel to knock young watersprouts off my trees. They are weak and easily detach.
Sprouts that have hardened (older than a year) do need to be cut at the base off with whatever tools are appropriate to their thicknesses. When these are high in the tree and growing up from a branch, this is a real pain in the butt.
Using Watersprouts in Grafting
While they are a detriment to mature, established plants that need to have fast growth only at their tips for good structure, watersprouts are perfect wood for use as scions in grafting. Because of watersprouts, it is possible to get young cuttings from a tree without going high into the crown. One-year-old wood is typically the ideal for scions.
The wood of suckers is juvenile and thus fast-healing and fast-growing. It is also thin and flexible, just what you want for many types of grafts.