Burr Oak – Simcoe County Master Gardener

Simcoe County Master Gardeners

Grow Natives!

PLANT PROFILE

COMMON NAME: Bur Oak

SCIENTIFIC NAME: Quercus macrocarpa

Family	Beech
Cdn Native Range	all of SK, MN, ON, NB
Natural habitat	Deep, rich bottomlands to rocky uplands; grasslands
Features	The most common native member of the white oaks. Showy acorns are large, knobby and often fringed. Its fall colour is less interesting compared to other oaks.
Growth habit	Trunk grows straight to the upper crown. In exposed shallow soil, trees may be stunted; deep taproot; slow-growing.
Mature height	24–36 m
Mature trunk width	60–80 cm
Life span	200 years
Cdn Hardiness Zone	3a–8b
Growing conditions	Sun to part shade
Soil conditions	Dry to moist
Watering needs	Supplementary watering for the first 2–3 years
Tolerance	Drought and salt tolerant; some shade tolerance; fire; urban conditions
Pruning needs	None beyond removing dead, diseased, or damaged branches.
Bloom	Tiny male (yellowish) and female (reddish) flowers bloom in spring
Fruit	acorns as noted above
Pollinator support	Nectar and sap for pollinators; early spring pollen for bees. Larval host for 8 butterflies including the banded hairstreak and white admiral; larval host for hundreds of moths including eclipsed oak dagger and waved sphinx.
Environmental support	A biodiversity hub hosting insects over their life cycle. Overwintering shelter and leaf litter habitat for insects that are the base of the food web for birds and their young. Birds also eat oak foliage and acorns and find nesting sites in oaks.
Garden Use	Roadside, boulevard, woodland, fence lines; shade; ornamental
Risks & Cautions	Massive root system, limb drop, leaf drop, shade, oak wilt disease, some insect pests
Cynthia’s Notes	World-renowned environmentalist Doug Tallamy advises everyone to have at least one oak tree (especially a white one like the bur oak) due to its status as a keystone species.

References: John Laird Farrar, Trees in Canada; Linda Kershaw, Trees of Ontario; Lorraine Johnson’s and Sheila Colla, A Garden for the Rusty-Patched Bumblebee; Heather Holm, Bees: An Identification and Native Plant Forage Guide.