Winterberry Holly

Size, growth and what to expect

Winterberry holly comes as male or female plants, and only the females carry the bright red quarter-inch berries. Our growth estimator models it as a medium shrub, roughly a foot and a half of new height a year in its youth on an average site. It makes a rounded shrub 6 to 12 feet tall and as wide, and it often suckers into a thicket.

Small greenish-white flowers open in the leaf axils in June and July, and one male within 50 feet pollinates a group of females. The berries ripen from August into fall and hang on the bare stems through the winter and often into early spring. More than 48 kinds of birds eat them, and the shrub hosts the caterpillars of Henry's elfin butterfly.

It grows wild from Nova Scotia west to Minnesota and south to the Florida panhandle and east Texas, in swamps, damp thickets and low woods and along ponds and streams.

How to grow Winterberry Holly

Winterberry holly takes full sun or light shade, in moist soil or ground that floods, with more berries in sun. Soil must be acid; in limey ground the leaves yellow and the plant dwindles. Shrubs slowly widen by suckers, so space a group 5 feet apart.

Plant dormant bare-root or potted plants between leaf fall and bud break, in a hole wider than the roots and no deeper. Set the crown at grade, put the native soil back in, and lay a mulch ring that stops short of the stems. No amendments, no stake. Seed needs a warm spell and then a winter. Sow it outdoors in fall a quarter inch deep, and seedlings come up the second spring. For a spring sowing, keep it in a damp bag for two months at room temperature and then two months in the refrigerator.

Water weekly the first two summers unless the site stays wet. Deer browse the young growth and rabbits cut stems in winter, so cage it for two years. It flowers on new wood, so any pruning goes in late winter, and little is needed; cut a few of the oldest stems out every few years to keep it full.

Winterberry is male or female and seedlings do not show which until first bloom, a few years in, so plant a group so that a male lands among the females. The berries are toxic to people and pets, though birds take them once winter hardens.