Bur Oak

BUR OAK—QUERCUS MACROCARPA-MOSSY CUP OAK

         One of the most successful oaks for Colorado is the Bur Oak. It is adaptable to our clay soils and tolerates our alkaline conditions better than most oaks. In harsh, droughty areas this tree can be a low shrub, but on rich, river-bottom land can get 170’ high and 6’-7’ in diameter; but most often grows 50’-70’ high. The trunk is often thick and short with deeply furrowed bark, and the stout branches often extend almost straight out making the tree as broad as tall. The leaves are deeply lobed only in the bottom half and these lobes are rounded not pointed as with many other oaks. The acorns are distinctive in that there is a mossy fringe around the cap. The overall effect can be quite grand and sculptural, sometimes like a Chinese painting. The short taproot is surrounded by a massive root system which is strongly competitive. This is why old specimens often are standing alone.

         The Bur Oak is hardy to zone 2, withstands strong wind, city pollution and drought. However even a little extra water will make them grow faster and larger. Since they are somewhat difficult to transplant, pot-grown seedlings are a good choice, as are smaller ball-and-burlap plants. Fall color is usually yellow turning to brown, but sometimes red. They can live for 300 years or more.

         This is a tree we can plant for our children, for future generations or even for our old age. One of the difficult tree questions is, “What is a good tree to plant on the west side of a house in a windy area?” Quercus macrocarpa is a good choice because it is strong and holds up well. In our later years, it will need little maintenance and will provide great shade from the late afternoon sun. True, oaks are slower-growing than maples and ashes, but there are some wonderful specimens around to attest to the worthiness of patience.