Boxwoods are a popular choice for many landscapes, offering year-round greenery and structured form. Understanding their root system is important for successful establishment, long-term health, and informed decisions about planting and care.
Understanding Boxwood Root Systems
Boxwoods have a fibrous root system, not a single deep taproot. They produce a dense network of fine, hair-like roots that spread outwards in the upper soil layers. These roots efficiently absorb water and nutrients from the topsoil, making boxwoods responsive to surface moisture and feeding.
Typical Root Depth and Spread
Boxwood roots typically remain in the top 15 inches of soil, with most feeder roots concentrated in the upper 6 to 12 inches. While shallow, their lateral spread can extend 1.5 to 2 times the width of the plant’s foliage, often beyond the visible canopy.
Several factors influence root depth and spread. Soil type plays a role; roots may penetrate deeper in loose, well-draining soils like sandy loam, but remain shallower in compacted or heavy clay soils due to reduced oxygen and drainage. The boxwood’s age and size also dictate root development, with mature, larger specimens having more extensive root systems.
Planting and Care Considerations
Given their shallow root system, plant boxwoods at the correct depth. They should be planted at the same level as their nursery container, or slightly higher, with the top of the root ball just above the soil line to prevent root rot. This elevated planting promotes proper drainage around the root crown. When planting multiple boxwoods, consider their mature size and root spread, allowing adequate spacing to minimize root competition.
Consistent moisture is important for boxwoods due to their shallow roots. Water frequently but avoid excessive deep watering, as feeder roots are near the surface. Applying a 2 to 3-inch layer of organic mulch around the base helps retain soil moisture, regulate soil temperature, and suppress weeds. When fertilizing, surface applications of slow-release granular products are effective, as the roots are positioned to absorb nutrients from the topsoil.
Addressing Root-Related Concerns
Boxwood roots, being shallow and fibrous, can compete with other plants or turfgrass if planted too closely. An adequate buffer zone around boxwoods prevents competition for resources. Concerns about boxwood roots damaging structures like foundations or sidewalks are unfounded. Their fine root system lacks the force to crack concrete or disrupt sturdy structures. Instead, they are more likely to exploit existing cracks than create new ones.