Prickly-ash is a tall, colony-forming small tree or large shrub reaching 15 to 25 feet tall and wide. Twigs and stems are covered in 1/2 inch prickles making it difficult to use in the landscape. In spite of its common name, it is not related to ash trees (Fraxinus spp.) of the Olive family. Rarely found in the nursery trade.
This species is native to the Chicago Region according to Swink and Wilhelm’s Plants of the Chicago Region, with updates made according to current research.
- Family (English) Rue
- Family (botanic) Rutaceae
- Tree or plant type Tree, Shrub
- Foliage Deciduous (seasonally loses leaves)
- Native locale Chicago area, Illinois, North America
- Size range Large shrub (more than 8 feet), Compact tree (10-15 feet), Small tree (15-25 feet)
- Light exposure Full sun (6 hrs direct light daily), Partial sun / shade (4-6 hrs light daily)
- Hardiness zones Zone 3, Zone 4, Zone 5 (Northern Illinois), Zone 6 (City of Chicago), Zone 7
- Soil preference Moist, well-drained soil, Wet soil
- Tolerances Alkaline soil, Clay soil, Dry sites, Occasional drought, Occasional flooding, Wet sites
- Season of interest late summer
- Flower color and fragrance Inconspicuous
- Shape or form Multi-stemmed, Thicket-forming
- Growth rate Moderate