Old Canaan Building Materials

Boxwood is the hedge plant of the traditional New England garden. Low, dense, evergreen, slow-growing, easily sheared to any form — it defines the edges of parterres, frames the entries of paths, borders the kitchen garden, and gives winter structure to landscapes that would otherwise disappear entirely under the grey of a Connecticut December. It has been doing these things in this region since the colonial period. It is also, at this moment, under serious pressure from a fungal blight that has killed boxwood plantings across the Northeast and forced a genuine reconsideration of the plant.

Boxwood has a smell. It is specific and not universally loved — slightly acrid, vegetable, dense. On a warm afternoon in a walled garden where old boxwood has been growing for decades, the smell is the garden's signature as much as its form. Visually, boxwood at its best is dense and dark, holding a crisp edge for months after shearing, reading from any distance as a firm line between the cultivated and the uncultivated. Nothing else does this quite as well over quite as long a season in a New England climate.

Boxwood blight, caused by the fungus Calonectria pseudonaviculata, arrived in the United States around 2011 and has spread rapidly across the Northeast. English boxwood is highly susceptible. Resistant varieties have been developed — NewGen Independence shows strong blight resistance in trials and maintains the tight growth habit and dark color that makes boxwood useful as a hedge plant. The honest assessment: boxwood is not going away, but the species requires more careful selection than it once did.

Inkberry holly, Ilex glabra Shamrock, is the most useful native alternative for low hedges. It holds its form well, is deer-resistant, tolerates wet conditions that would kill boxwood, and takes shearing adequately. Its color is slightly lighter and its texture slightly coarser than boxwood, but from a distance a well-maintained inkberry hedge is a credible substitute in many applications.

Bayberry, Myrica pennsylvanica, grows more loosely and does not take shearing as precisely, but has a native legitimacy that makes it right for informal hedge applications along driveways and at property boundaries. Japanese holly, Ilex crenata Helleri, closely approximates boxwood in texture and color and takes shearing precisely — appropriate for low formal hedges where inkberry's coarser texture is not quite right.

For new formal hedge plantings, specify boxwood in blight-resistant varieties in areas with good air circulation and well-drained soil. In areas with known blight pressure or poor drainage, substitute inkberry Shamrock. For existing boxwood, improve air circulation through thinning, remove and destroy affected plant material, avoid overhead watering, and replace losses with resistant varieties rather than like-for-like replacement with susceptible material.