Burr Oak

zone map
sun
tree shape
Hardiness Zone Mature Spread Mature Height Growth Rate Sun Tree Shape Soil Type
3-8 80' 100+ slow full wide, spreading most types
Photo of bur oak tree

Description

uercus is the Latin name for oak. Macrocarpa comes from the Greek Makros meaning "large" and karpos meaning "seed" in reference to the large acorns. Other common names for bur oak are mossycup oak and scrub oak. The tree is known by the Lakota as u'tahu can, meaning "acorn stem tree." Other American Indians referred to bur oak as tashka (Omaha), chashke (Winnebago), and patki natawawi (Pawnee).

The bur oak is in the family Fagaceae along with the other oaks, beeches and chestnuts. Bur Oak has a very long life span. Trees with a two-foot trunk diameter are often more than 200 years old with 300 to 500 year old-old trees occasionally found. The tree adapts to a wide range of soil conditions from moist, slightly acidic to dry and alkaline. It is considered slow growing but young, properly mulched and watered trees can grow over 15 inches per year. This is a large tree that often reaches over 100 feet tall with a long clear bole. In the open it becomes a very wide, spreading tree.

Photo of bur oak leaf

Leaf

Alternate, simple, 6 to 12 inches long, roughly obovate in shape, with many lobes. The two middle sinuses (define) nearly reach the midrib dividing the leaf nearly in half. The lobes near the tip resemble a crown, green above and paler, fuzzy below. Bur oak usually has a rather poor fall color, yellow-green to yellow-brown.

Photo of bur oak flower

Flower

Monoecious male flowers are yellow-green, borne in long, drooping slender catkins, 2 to 4 inches long; female flowers are green tinged in red and appear as single, short spikes, both appear shortly after the leaves.

Photo of acorn

Fruit

Acorns are quite large (1 1/2 inches long) and 1/2 enclosed in a warty cap that has a long-fringed margin, maturing in one growing season in late summer and fall.

Photo of bur oak twig

Twig

Quite stout, yellow-brown, often with corky ridges; multiple terminal buds are small, round, and may be somewhat pubescent often surrounded by thread-like stipules (define); laterals (define) are similar, but smaller.

Photo of bur oak bark

Bark

Ashy gray to brown in color and quite scaly, but noticeably ridged vertically on large trees.

Bur oak distribution in South Dakotabark

Distribution

Bur oak is one of the most widely distributed oaks in eastern North America. Its natural range extends from New Brunswick to extreme eastern Wyoming. Bur oak is found as far north as central Manitoba and south to central Tennessee and southern Texas. It is found throughout South Dakota except in the extreme southwest corner of the state.

Bur oak tolerates a wide variety of soil and moisture conditions. It is found along the dry slopes of the Ohio River and the moist bottomlands of the Mississippi River. It a transitional species between the prairie and the eastern forests.

In South Dakota, bur oak is found on the terraces along streams and in the adjacent draws. It often grows to the top of the slopes and becomes the first tree to be established on the prairie. The growing conditions near the top of the slope are much harsher. Along the Missouri River, it is not uncommon to find bur oak as large trees near the base of the slopes and as bushes near the top.