Sumac (Rhus spp.) is a deciduous shrub or small tree known for its attractive fall foliage and colonizing habit. Its vigorous growth, particularly its expansive root system, often concerns gardeners, highlighting its management needs.
Understanding the Sumac Root System
Sumac develops a distinctive, colonizing root system. Its roots are shallow, typically extending only about 10 inches deep, spreading horizontally as an extensive, fibrous network near the surface. This wide-spreading habit allows sumac to quickly establish and thrive in various soil conditions, including dry or disturbed areas.
Sumac’s aggressive spread relies on rhizomes, underground stems that function like roots. These extend outward, often several feet per year, producing new shoots (suckers) far from the original plant. This suckering allows sumac to form dense thickets and rapidly colonize areas, as each sucker can develop into a mature plant.
Challenges Posed by Sumac Roots
Sumac’s aggressive root system presents several landscape management challenges. Its prolific suckering leads to rapid colonization into garden beds, lawns, and natural areas. This unchecked growth transforms single plants into large, dense thickets, creating an unruly appearance.
Removing established sumac is difficult; cutting the main plant often stimulates more suckers from its extensive underground root network. Mechanical removal is a continuous battle, as new shoots frequently emerge from remaining root fragments. The dense root system also competes with other desirable plants for water and nutrients, displacing existing vegetation. Sumac colonies can alter soil chemistry and light levels, hindering other plant growth.
Though less common than with large trees, sumac’s shallow, spreading roots can cause minor structural issues. Extremely shallow roots might, in rare instances, lift pavement or crack shallow foundations. However, primary concerns for most property owners relate to the plant’s aesthetic impact and its tendency to overwhelm other garden plants.
Managing and Controlling Sumac Roots
Effective sumac root management begins with careful pre-planting consideration, ideally choosing less aggressive species for smaller spaces. If sumac is desired, planting it with a root barrier, at least 24 inches deep, can contain its spread by preventing rhizomes from unwanted areas.
For existing sumac, physical removal methods are effective, especially for smaller plants or new suckers. Digging out suckers and their connecting root sections prevents regrowth. Repeated efforts are often necessary, as any remaining root fragments can produce new shoots. Mowing new suckers regularly can also deplete the root system’s energy reserves.
Chemical control using systemic herbicides is another approach, especially for larger infestations. Herbicides like glyphosate or triclopyr can be applied to cut stems or directly to foliage. These systemic chemicals are absorbed and transported to the root system, killing the entire plant. Follow product instructions carefully, applying herbicides during the plant’s active growing season for maximum effectiveness. Consistent monitoring and removal of new suckers, manually or chemically, remain crucial for long-term control and re-establishment prevention.