Aspen 'Quaking' (Populus tremuloides) is a deciduous tree known for its distinctive white bark and quivering leaves that rustle in the wind, hence its common name. It typically grows to a height of 20 to 50 feet and a spread of 15 to 30 feet at maturity, with a narrow, upright habit. However, it can grow up to 70 feet tall in optimal growing conditions. The leaves of 'Quaking' aspen are small, round, and bright green in the spring and summer, turning to shades of yellow in the fall. This tree is tolerant of cold temperatures and can grow in a wide range of soil types, making it a popular choice for landscaping and gardens in colder regions. Keep in mind that the growth rate and size may vary depending on the specific growing conditions and location.