The prickly ash (Zanthoxylum americanum) also known as the northern prickly ash or the toothache tree, is a shrub that grows 4 to 10 feet (maximum 25 feet). It has paired prickles flanking the leaf scars and buds, and encountering a specimen without prickles is very rare.
Habitat: This thicket forming shrub or small tree can be found in clearings, open woods and woodland edges on wet or dry soils.
Hardiness: Zones 3 through 9
Growth Rate: Moderate to Fast
Mature Shape: Slightly pyramidal, upright with a rounded crown
Height: 50-80 feet
Width: 50-70 feet
Site Requirements: Native to Iowa, ash trees grow best in full sun and moist, well-drained soils. Ash trees are tolerant of a wide range of soil conditions.
Flowering Dates: May - June
Seed Dispersal Dates: September - October
Seed Bearing Age:
Seed Bearing Frequency: Yearly
Seed Stratification: Prechill for 4 months at 34°F to 40°F
The leaves are 3 to 10 inches, compound, 5 to 11 toothed egg-shaped leaflets with prickly leafstalks.
Flowers are small, green, clustered and bloom in April and May. Fruit are small, dry, red-brown, 1 to 2 seed pods that produce from August to October.
Chewing the leaves, fruit, or bark was once thought to cure a toothache, and if you crush the foliage it will emit a distinctive lemon scent.