The southwestern state of Arizona falls within United States Department of Agriculture (USDA) Hardiness Zones 5 to 10. Much of Arizona experiences an arid climate with hot summers and mild winters. Northern Arizona has a higher elevation, which brings milder summers and colder winters. If you live in Arizona, select flowering trees for your zone according to the tree’s cultural requirements, intended use, bloom information and mature size.
The Arizona madrone (Arbutus arizonica), belongs to the heath family (Ericaceae) and prefers dry, rocky soils in fully sunny locations. This slow-growing tree reaches 45 feet in height. The Arizona madrone bears oval, evergreen leaves and pink-brown bark. Small, white or pink blossoms appear from May through August, followed by tiny, red or orange berries that attract birds. The Arizona madrone works well in landscapes at higher altitudes.
Cigar trees (Catalpa bignonioides), sometimes referred to as southern catalpa trees, belong to the trumpet-creeper family (Bignoniaceae) and range from 25 to 40 feet in height and spread. The heart-shaped, pale green, deciduous leaves have prominent veins and a foul smell when they are bruised or crushed. Flower clusters bloom in May and June, featuring white flowers with purple stripes and yellow spots. These blossoms are followed by fruit pods that look like little cigars. This tree prefers moist to wet soils that receive some shade. Arizona gardeners often plant the cigar tree as an ornamental shade tree.
The desert willow (Chilopsis linearis), sometimes called the flowering willow or the willow-leaved catalpa, belongs to the Bignoniaceae plant family and needs fully sunny positions. Mature desert willows range from 15 to 40 feet in height. This deciduous tree features thin twigs, leaning trunks and pale green leaves. Funnel-shaped, deep pink or purple flowers smell like violets and bloom from April through September. This drought-tolerant plant adapts to Arizona’s dry soil conditions. The desert willow performs well along streams, ditches, rivers and desert washes.
Desert ironwoods (Olneya tesota), also known as tesota trees, belong to the pea family (Fabaceae) and reach up to 30 feet in height. This evergreen tree bears thorny branches, dark brown bark and hairy, grayish-white foliage. Many purple or pink, pea-like blossoms appear in April and May, followed by seedpods that attract desert wildlife. Desert ironwoods prefer dry, sandy or rocky soils in sunny positions. Arizona gardeners often plant the desert ironwood in desert washes and lower desert areas.
The wafer ash tree (Ptelea trifoliate), also called the common hoptree, belongs to the rue family (Rutaceae) and bears aromatic, deep green leaves that turn shades of yellow in autumn. Mature wafer ashes reach up to 36 feet in height. Clusters of tiny, green-white flowers bloom in April, followed by winged, bitter fruits that feed the local birds. These fruits are sometimes used as substitute for hops in beer recipes. The wafer ash tree tolerates various lighting conditions, but prefers well-drained, loamy soils. Arizona gardeners often use the wafer ash tree as an understory tree in rocky areas.