English holly

Ilex aquifolium

Evergreen tree or shrub with glossy spiny leaves and bright red winter berries. The traditional Christmas holly of the British Isles.

Hardiness ratings

English holly hardiness across the four zone systems
SystemRatingTemperature rangeHow to read it
USDA hardiness zone Zone 5–9 −28.9 °C to −1.1 °C Plant tolerates down to this zone
RHS hardiness rating H6 −20 °C to −15 °C Plant needs at least this level of cold tolerance
Canadian plant hardiness zone Zone 6–9 −18 °C and warmer Plant tolerates down to this zone
Australian (ANBG) zone Zone 2–6 −10 °C to 15 °C Plant tolerates down to this zone

About English holly

Holly is dioecious — individual plants are male or female — so berries only appear on female plants, and only when a male is within range of pollinators. This is the usual reason a well-grown holly never berries, and it is complicated by cultivar names that are actively misleading, with some well-known male cultivars carrying female-sounding names. The famously spiny leaves are not uniform: the same tree usually produces much smoother leaves higher up, out of reach of browsing animals, which is a well-documented response to grazing pressure.

Growing notes

  • Larval host plant for the spring generation of the holly blue butterfly
  • Bright red berries through winter are an iconic Christmas / midwinter seasonal marker
  • Separate male and female plants — only female plants set berries, and a male must be in flowering range for pollination
  • Excellent dense windbreak and stockproof boundary

Pet caution: English holly is listed as potentially harmful to cats and/or dogs. Keep pets from grazing on it, and contact a vet if you suspect your animal has eaten some.

Categories

Related plants

Cross-check English holly against your zones

Reference

English holly on Wikipedia