The bur oak is a native tree and broadly distributed throughout the Midwestern U.S. It is known to be tough and drought resistant -- and very large. While its size makes it impractical for most home landscapes, its resilience makes it a good choice for urban parks. The bur oak is one of the signature trees of the savannas characteristic of Illinois prior to settlement.

A thick trunk supports the relatively short, muscular branches of the bur oak's broad crown. The acorns, which mature annually, are easily recognized by their heavily fringed cups. Bur oaks grow in open habitats in full sun, rather than dense woods. There are nearly 500 bur oaks in the Chicago Botanic Garden's collection.

The genus Quercus includes more than 600 species of the oak tree, of which 90 are native to North America; the Chicago Botanic Garden's collection contains more than 60 varieties and over 1,000 individual trees. Twenty oak species are native to Illinois.

Oaks are slow growing, long lived, hard wood trees that produce fruit we all know as acorns. Within the white oak group, acorns mature annually; in the red oak group, acorns take two years to mature (biennial). Oaks are often imposing shade trees at maturity and provide habitat and food for a variety of wildlife.