Rocky Mountain Glow Maple lives up to its name in the fall. This seedling selection of Bigtooth Maple (Acer grandidentatum)is proving to be a good smaller tree for the Rocky Mountain states and other areas where it is adapted. Fall color in its native range is bright red, with red to orange tones reported in other regions. This close relative of the Sugar Maple is found in moist canyons throughout the Rocky Mountain Range, from Wyoming south into Mexico. Smaller and slower-growing than Sugar Maple, it is cold hardy (Zone 4) and a nice addition to the handful of smaller shade trees that are suitable for colder climates. Rocky Mountain Glow Maple was selected by Keith Warren, our staff horticulturist, from a group of Bigtooth Maple seedlings grown from a Utah seed source. The parent tree was chosen for good fall color as well as a vigorous growth habit that made it a good performer in the nursery. Our selection matures in an oval shape to an approximate height of 25 feet and spread of about 15 feet. It is budded onto Sugar Maple understock. Though Rocky Mountain Glow Maple was selected for the Rocky Mountain States, it is proving adaptable to other areas. Distributed in 1990 to numerous test sites across the United States, it has received good reviews from several evaluators in North Central and Northeastern states as well as in its native range. Although slow growing after transplanting, it shows good promise as a smaller street tree in areas where it has established itself.