Quaking Aspen
(Populus tremuloides)
Quaking Aspen fall color
Quaking Aspen (Populus tremuloides) grows in groves throughout the cooler climates in North America. Groves are characterized by a number of stems rising from the same root system, sharing the same DNA. One Utah grove has nearly 50,000 stems, weighs 6,000 tons and covers 100 acres. It is believed to be the largest living thing on Earth. While what appears to be a single tree may live only 50 or 60 years, new stems can keep a grove going for tens of thousands of years.
Flat, heart-shaped leaves with finely toothed margins extend alternately from branches on long, thin petioles (stalks) allowing them to flutter in the slightest breeze. This is the origin of the common names Quaking or Trembling Aspen.
Individual trees can grow to 90 feet in height. The bark is gray-white with horizontal black markings and knots. While the bark resembles Paper Birch, it does not peel. Quaking Aspen is deciduous, shedding its golden yellow leaves each fall. But unlike most deciduous trees, the bark has a layer that uses photosynthesis during the winter, producing sugars for energy.
Quaking Aspen bark
This perennially green bark layer attracts deer, moose and elk during hard winters as a food source. Vertical black marks on Quaking Aspen trees are the scars from wild herbivores seeking nutrients.
Quaking Aspen flowers appear as catkins in spring usually before the leaves. Male and female flowers are on separate plants. The female catkins produce tiny seeds covered in fluffy cotton-like fibers. The seeds burst free when mature and are dispersed by wind.
In the wild, Quaking Aspen serves as a food source and shelter for many creatures. Nuthatches and owls nest in old trunks. Beaver girdle and cut trees for their dams. Ruffed grouse depend on Quaking Aspen for food and nest sites. Buds, bark, twigs and fallen leaves serve as food for a variety of wildlife.
Mankind also has many uses for Aspen varieties. Because the wood is relatively hard and does not splinter, it is ideal for playground equipment, popsicle sticks and tongue depressors. It is also used in furniture, particle board and paper. Light in weight relative to its strength, Aspen is favored for shipping crates and pallets.
Because of its unique underground root system, Quaking Aspen survives wildfires and regenerates quickly providing a canopy for native conifers and other species to re-establish. In the fall, the trees in a Quaking Aspen grove all turn color at the same time creating a breathtaking display of brilliant yellow patches against dark green, conifer covered mountainsides.
In the garden, this member of the willow family seeks moisture and should be planted away from drain fields, septic systems and water lines. Quaking Aspen is fast-growing and can be aggressive. It is best planted in moist soil as windbreaks and for visual screening. It tolerates part shade, but does require at least four hours a day of full sun. The fluttery leaf movement and fall color add visual interest.
There is a Quaking Aspen grove in the North Idaho Native Plant Arboretum. Open to the public, parking for the Arboretum is at 611 S. Ella Ave. in Sandpoint, ID. The tree is described and pictured on page 52 of the KNPS publication, Landscaping with Native Plants in the Idaho Panhandle, available at local bookstores and the Bonner County History Museum.
Native Plant Notes are created by the Kinnikinnick Native Plant Society. To learn more about KNPS and the North Idaho Native Plant Arboretum, explore www.nativeplantsociety.org.