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Oak Wilt Update
OAK WILT ADVISORY
July 15th 2008
STATUS: LOW RISK
FORECAST: Expect safe period to begin around November
EXPECT NEXT UPDATE: November 15, 2008
FIELD NOTES: The low risk period has begun. Note that low risk does not mean "no risk." While the threat has decreased, trees should not be pruned or wounded unless absolutely necessary.
J. Juzwik
Northern Research Station, U.S. Forest Service
Tree of the Month
Three-Flowered Maple (Acer triflorum)
A native of Manchuria and Korea, Acer triflorum is an under-used, highly adaptable tree for the urban landscape. It is hardy to zone 3b as long as the soil drains well and is not too alkaline. Three-flowered maple grows equally well in full sun to moderate shade, taking on a dense, rounded growth habit in sunny landscapes, while stretching to a more upright and open form in shadier gardens. Ultimately, it is a small tree reaching a mature size of 25-30 feet in height and close to that in width, perfect for small lawns and gardens.

Its trifoliate, compound leaf is equally attractive in summer and autumn, but many people will mistake it for a small sugar maple from a distance when it turns its fall color. Bright orange and red autumn foliage lasts well into the autumn, similar to sugar and red maples. The samaras are larger than sugar maples but are attached at a narrow angle which is similar to sugar and red maples.

To many people, the most enduring and attractive feature of the tree is its bark. Multi-colored and exfoliating, the bark provides a landscape interest for the entire year. Do not buy this plant for its flower; plant it for its bark, character of its foliage and the autumn color.

Three-flowered maple grows slower than some of the other maples, which makes it a perfect tree for the landscape. It’s easy to prune to a good form and grows tall enough to raise the canopy for a patio or lawn tree. Ten years ago it was difficult to find Acer triflorum in nurseries, but it is now available in many good garden centers and retail nurseries as a containerized or balled-and-burlapped tree.
Photos courtesy of Gary Johnson
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