Oaks are venerable trees. They can make us feel protected and provide shade in an otherwise unsheltered prairie. Oak trees are majestic beauties and symbols of strength in many cultures. The oak is the national tree of not only the United States, but of England and Germany as well.
There are about 400 species in the oak genus (Quercus) worldwide. The Oak Collection at The Morton Arboretum contains many well-documented oak species and hybrids. The collection features 98 unique taxa, or different kinds, and over 468 plants in the collection from North America, Asia, and Europe.
In 2009, Botanic Gardens Conservation International determined that the Oak Collection at The Morton Arboretum is the most significant botanic garden collection of oaks among 198 botanical institutions worldwide.
The collection is distributed across 12 acres on the East Side of The Morton Arboretum. The site was originally an oak-dominated upland forest before European settlement. During the 1800s, forest products were harvested and the cleared areas were farmed. As evidence of this original landscape, many mature white oaks (Quercus alba) and bur oaks (Q. macrocarpa) commonly occur in the Oak Collection and throughout the Arboretum.
Oak Species at The Morton Arboretum
Native oak species are particularly well represented. Seventeen species out of the total 21 Illinois native species, including white oaks, are growing in the collection. The white oak is the Illinois state tree and a symbol of Midwestern history and landscape.
Another exciting and native oak species is the bur oak (Q. macrocarpa). Look for this oak’s large acorns with their tough bristly caps, and spreading horizontal branches. Find the swamp white oak (Q. bicolor), and look at its leaves to figure out how it got its scientific name.
Some new and interesting species added to the collection include a Turkey native, Hartwiss’ oak (Quercus hartwissiana); a Chinese native, Liaotung oak (Quercus liaotungensis); and a Japanese native, gland-bearing oak (Quercus serrata).
The Oak Collection provides an excellent site to study the diversity of oaks.
