Boxwood Tree Moth

The future for Boxwood looks grim.

Boxwood, abroadleaf evergreen, has long been a staple for landscaping.  It is appreciated for its hardiness, smallglossy leaves, and slow growth.  Boxwoodgrows in sun or shade, and in poor or rich soil. 

The enemy is BoxTree Moth and it is at our doorstep.   Firstdetected in Toronto in 2019, the pest has since been found in NiagaraPeninsula, Ontario’s breadbasket of nurseries. Earlier this year it was discovered in London and Windsor. 

How quickly itarrives in Sarnia Lambton is anybody’s guess, and how quickly it will affectall boxwoods is another guess. 

Box Tree Moth,like all moths, goes from larvae to caterpillar to adult moth.  Eggs are laid near the host plant and thecycle repeats itself.  It is thecaterpillar stage that does most damage. 

Fortunately,BTK, a natural insecticide, is an effective control to prevent the spread ofBox Tree Moth.  If applied whencaterpillars are active, BTK will keep Boxwoods free from danger.  But spraying Boxwood plants for the nextseveral years seems impractical. 

Nursery growershave been quick to get on the bandwagon to find alternatives to Boxwood, shouldthe inevitable happen quickly. 

For gardenerswho don’t mind switching from evergreen to deciduous there are plenty options,including Spirea, dwarf varieties of Hydrangea, Deutzia, Weigela andBarberry. 

For gardenerswho prefer evergreens, Yews are the obvious choice.  Yews come in several shapes and sizes, allwilling to grow in sun or shade, and in poor or good soils.  Nursery growers in Ontario are already reportingthat Yews of all kinds will be in short supply in coming years, because ofanticipated demand. 

Yews are darkgreen, soft needled evergreens that will make a fine substitute forBoxwood.  Most varieties are faster andlarger growing than Boxwood but can easily be pruned to keep in check.

The most popularYew, Hicks, is a taller growing evergreen that makes a wonderful hedge to offeryear-round privacy.  Hill’s Yew is like ayounger sibling, growing slower, and denser than Hicks. 

Fairview andDense Yew have a spreading habit with a tendency to grow wider than tall.  Both are easy to trim and keep shaped in atight globe or dwarf hedge. 

The odd Yew, myfavorite, is Emerald Spreader, a low-growing plant that will not grow more than12 inches high.  Slow growing and wellbehaved, Emerald Spreader is ideal for planting under low windows.  If planted in groups, and if not pruned,Emerald Spreader Yew will eventually form a dense groundcover.