Tree suckers are fast-growing, opportunistic shoots that emerge from the base of a tree or directly from its root system. These growths are essentially clones of the rootstock, and they rapidly divert energy and nutrients away from the main, desirable canopy of the tree. Left unmanaged, suckers can quickly mar the appearance of a landscape tree and compromise its long-term health and structure. Successfully eliminating them requires understanding their biological origin and applying targeted removal techniques.
Understanding Why Tree Suckers Form
Suckers are a tree’s natural response to stress, injury, or genetic programming designed for survival. These shoots originate from adventitious or latent buds located on the tree’s roots or the trunk below the soil line or graft union. Their rapid growth is an attempt to restore a balanced canopy after a loss of foliage or to reproduce if the main trunk is struggling.
It is helpful to differentiate suckers from water sprouts; suckers emerge from the roots, while water sprouts arise from latent buds on the trunk or upper branches. The underlying causes for both are similar, often including excessive pruning, physical damage from lawnmowers or construction, drought stress, or disease. Suckering is common in grafted trees, where the hardier rootstock attempts to re-establish itself, often resulting in shoots with different, less desirable characteristics than the intended tree variety.
If suckers are allowed to grow, they compete directly with the main tree for resources like water and nutrients, which can diminish fruit production. The dense, upright growth of suckers can also create a haven for pests and diseases, increasing the tree’s vulnerability to infection. Removing these growths is necessary for both aesthetic maintenance and health management.
Step-by-Step Guide to Mechanical Removal
The most effective method for managing suckers is mechanical removal, but simply clipping them at ground level often stimulates vigorous regrowth. This happens because the cut leaves behind dormant buds activated by the removal of apical dominance. The goal is to remove the growth point as completely as possible.
The proper technique involves tracing the sucker back to its point of origin on the root or trunk and removing it with a tearing action. For young, pliable suckers, grasp the shoot firmly and tear it downward and away from the parent plant. This action removes the basal meristematic tissue, which contains the dormant buds, significantly reducing the likelihood of immediate re-sprouting.
For thicker suckers that cannot be cleanly torn, use a sharp utility knife or bypass pruners to make a slicing cut directly against the trunk or root. If the sucker emerges from a root below the soil, scrape away soil to access the base and cut flush with the root surface. Leaving a small stub will result in multiple, more persistent shoots.
Mechanical removal is easiest when suckers are young and herbaceous, minimizing the wound size. Avoid using power tools like string trimmers or lawnmowers near the tree base, as the minor wounds they inflict on the bark and surface roots trigger new sucker growth. Consistent, early intervention is necessary to manage suckering without resorting to chemical measures.
Chemical Application and Long-Term Prevention Strategies
Chemical controls are reserved for persistent or widespread suckering, such as in commercial orchards. Applications fall into two categories: contact herbicides, which burn down foliage, and plant growth regulators (PGRs), which interfere with hormonal signals. Contact herbicides, such as those containing Carfentrazone-ethyl, must be applied cautiously, targeting only the sucker foliage to avoid drift damage to the parent tree.
PGRs, like formulations containing Naphthalene Acetic Acid (NAA), are often applied as a localized spray or paste to the cut surface of a removed sucker or the base of the tree. These chemicals suppress the activation of latent buds, preventing new shoots. Follow label directions precisely when using chemical solutions, using low-pressure sprayers with large-droplet nozzles to minimize drift.
Long-term prevention is the most sustainable approach, focusing on minimizing environmental stresses. Adequate water and proper fertilization help maintain a stable system less inclined to produce stress shoots. Avoid deep cultivation or tilling within the tree’s dripline, as root damage stimulates new sucker growth.
When planting new trees, selecting species or cultivars known to sucker minimally reduces future maintenance. For grafted trees, choosing stock grown on its own root system or a rootstock known for low suckering prevents the genetic incompatibility that drives the problem. Protecting the tree’s root zone offers the best defense against recurring suckers.