Sumac is a common shrub or small tree found in many landscapes, known for its vibrant fall foliage and distinctive fruit clusters. Understanding the characteristics of its root system is important for anyone considering planting sumac or managing its growth.
Understanding Sumac Root Systems
Sumac species primarily spread through an extensive network of lateral roots, rather than a deep taproot. This root structure allows the plant to form dense thickets and colonies. Smooth sumac (Rhus glabra) and staghorn sumac (Rhus typhina) are notable for readily producing new shoots, often called suckers, from their widespread root systems. The root system is generally shallow and fibrous, which aids in its rapid spread across an area. These shallow roots are effective at absorbing moisture and nutrients from the upper soil layers.
Typical Root Depth and Lateral Spread
Sumac roots are typically shallow, with many species, such as staghorn sumac, having roots that reach depths of about 10 inches underground. Smooth sumac’s rhizomes, which are underground stems, are usually found between 3 to 12 inches below the soil surface. While the majority of the root system remains relatively shallow, the main roots of smooth sumac can extend deeper, potentially reaching 7 to 8 feet.
The lateral spread of sumac roots is significant. Staghorn sumac can extend its wide-spreading, fibrous root system outward by three or more feet per year. Smooth sumac also spreads vigorously through rhizomes, with new shoots emerging as far as 30 feet from the parent plant, forming extensive colonies. Factors such as soil type, moisture availability, and the specific sumac species can influence the exact depth and spread, but the general pattern is one of shallow, wide-ranging root systems.
Implications of Sumac Roots
The extensive and shallow root system of sumac has several practical implications for gardeners and landowners. One significant concern is the potential for competition with other plants. Sumac’s aggressive spread allows it to quickly outgrow and displace other vegetation, monopolizing available water and nutrients in the soil. This can lead to the suppression of desirable plants, as sumac forms dense thickets that can even block sunlight.
The prolific suckering habit makes sumac challenging to contain within a defined area. These suckers can arise a considerable distance from the main plant, leading to the formation of large, interconnected colonies. This characteristic can make sumac a nuisance in cultivated gardens or near structures where its spread is undesirable.
Managing Sumac Growth and Roots
Managing sumac growth, particularly its expansive root system and suckering habit, requires consistent effort. For containment, planting sumac in an isolated bed or using a root barrier can help limit its spread. A metal or heavy plastic barrier around one foot deep is often sufficient to deter new suckers from emerging outside the desired area.
Regular removal of new suckers is crucial. Mowing young root sprouts can help control spread in lawns. For more aggressive control, cutting the plant and treating the stumps with an appropriate herbicide can minimize re-sprouting. Persistence is key, as any remaining root fragments can stimulate new growth, often requiring repeated treatments over several seasons to fully eradicate a sumac colony.