Mountain hawthorn (Crataegus douglasii) is a distinctive deciduous tree or shrub, recognized for its appealing characteristics that contribute to various landscapes. This adaptable plant offers unique features throughout the seasons, making it a notable presence and adding both structure and seasonal interest.
Recognizing Mountain Hawthorn
Mountain hawthorn grows as a thorny, multi-branched shrub or small tree, reaching 6 to 30 feet (1.8 to 9 meters) tall with a rounded crown. Its stout branches are armed with thorns, typically 1 to 2.5 cm long. The mature bark is rough and gray.
Leaves are green, thick, and oval, 1 to 5 inches (2.5 to 12 cm) long, with serrated or toothed margins, often lobed. They display yellow, orange, or red hues in autumn.
In mid to late spring, the plant produces fragrant, five-petaled white flowers, about 1/2 inch (1.2 cm) wide, in dense clusters. These blooms are followed by globular fruits, known as haws, which are about 1/2 inch (1.2 cm) across. Haws ripen from red to shiny black in late summer, often contain seeds, and can persist on branches into late fall.
Natural Habitat
Mountain hawthorn (Crataegus douglasii) is native to northern and western North America, with its most widespread occurrence in the Pacific Northwest, extending from southeastern Alaska south through British Columbia, Washington, and Oregon to northern California. It is also found inland across states like Idaho, Montana, Utah, and Wyoming, with some populations in the Great Lakes region.
This species thrives in diverse environments such as open woods, stream banks, and meadows. It commonly grows in moist to wet, humus-rich soils, but tolerates drier upland soils and various soil types. In its natural settings, it grows in full sun to partial shade, often forming dense thickets.
Growing and Caring for Mountain Hawthorn
For cultivation, choose a site with full sun to partial shade; full sun encourages more fruit. The plant adapts to various soil types but thrives best in well-drained, moist, loamy soil with a pH between 6.0 and 7.5. It tolerates heavy clay soils and some drought once established, though consistent moisture is beneficial. The best time for planting is during spring or fall.
Newly planted trees require regular watering, especially during dry periods, to support establishment. Mature hawthorns are somewhat drought-tolerant but benefit from watering during prolonged dry spells. Applying a mulch layer around the base helps retain soil moisture.
Pruning is best done in late winter or early spring while the tree is dormant, before new growth begins. This helps shape the plant and remove dead, diseased, or crossing branches. Young trees should establish and reach 4 to 6 feet before significant pruning. Fertilization is generally not required; however, if growth is poor, apply a balanced fertilizer in early spring.
Ecological Role and Uses
Mountain hawthorn provides significant ecological benefits, serving as a valuable wildlife resource. Its fruit, known as haws, feed many bird species (e.g., pheasants, quail) and mammals like bears. Dense, thorny branches offer protected nesting sites and cover for small animals. Flowers attract pollinators like bees and butterflies, supporting local insect populations.
Beyond ecology, mountain hawthorn is ornamental. Its white flowers, glossy green foliage, and black fruits add aesthetic appeal throughout the seasons. It can be used as a specimen tree, in native plant gardens, or for erosion control. Historically, fruits were eaten raw or cooked, used in pies and preserves. Its dense wood was used for tool handles, and thorns had traditional uses.
Addressing Common Issues
Mountain hawthorn is generally robust but can face pests and diseases. Common insect pests include borers, caterpillars, lace bugs, leaf miners, and scale insects. Signs include damaged leaves, stunted growth, or visible insects. Diseases like cedar-hawthorn rust, fire blight, fungal leaf spots, powdery mildew, and apple scab can cause discolored foliage, wilting, or branch lesions.
Environmental stresses, such as improper soil moisture (too dry or waterlogged), can weaken the plant. Though it tolerates some drought, prolonged dry periods are detrimental. Proper site selection and consistent care, including watering and soil conditions, minimize problems. Good air circulation from thinning branches also prevents fungal issues.