Leatherleaf Mahonia (Mahonia bealei)
Miller, J.H., E.B, Chambliss, N.J. Loewenstein. 2010. A Field Guide for the Identification of Invasive Plants in Southern Forests. General Technical Report SRS-119. Asheville, NC. United States Department of Agriculture, Forest Service. 126 p.
Evergreen shrub up to 10 feet (3 m) in height and branching to 4 to 8 feet (1.2 to 2.4 m) wide, erect and gangly or multi-stemmed from a pronounced root crown (with shallow roots). Leathery, odd-pinnately compound leaves radiate outward from the stem on long stalks with spiny, holly-like leaflets. Terminal, radiating stems of fragrant, yellow flowers in late winter to spring yield robin’s egg blue fruit covered by whitish wax, maturing to bluish black. Wood and inner roots bright yellow.
Terminal stem growth comprised of crowded and overlapping broad leaf bases, light green or purple on seedlings, soon developing thin, tan to gray, fissured bark. The clasping leaf bases remain greenish and spaced at intervals along stout stems.
Odd-pinnately compound, over 1 foot (30 cm) long on purplish stalks, stiff and spiraling out at intervals from the main stem with 9 to 13 leathery leaflets, 1 to 4 inches (2.5 to 10 cm) long. Leaflets with 5 to 7 extremely sharp marginal spines, holly-like, with no petioles and the terminal leaflet being largest. Lustrous green above with a lighter midvein and pale green beneath. Seedlings initially have simple heart-shaped leaflets on long petioles with many spines around the margins and often very white waxy beneath.
January to April. Plants are topped with 6 to 12 unbranched, bluish to purplish stems with lateral dangling yellow fragrant flowers, opening from base to tip.
Fruit and seeds
March to August. Many fleshy-skinned, egg-shaped berries, 0.4 to 0.7 inch (1 to 1.8 cm) long, dangle from bracts on a purplish stalk. Berries white waxy coated, light green turning robin’s egg blue and ripening purplish black, each with 2 to 3 seeds.
Moderate in growth rate in a full range of soil textures and light conditions, but prefers moist soils. Tolerates cold, however, young plants can be damaged by late frosts. Pollinated by insects. Colonizes by basal sprouts and spreads by many bird-dispersed seeds from ornamental and escaped plants. Seed from ripe fruit can immediately germinate. Hybridizes with other mahonias.
Resembles native subshrubs hollyleaved barberry [M.aquifolium (Pursh) Nutt.] and Cascade barberry [M. nervosa (Pursh) Nutt.], which are small, low growing, and have 6 to 13 spiny teeth around their leaf margins.
History and use
Introduced in 1845 from China, Japan, and Taiwan as an ornamental. Still being sold and planted by unsuspecting gardeners.
Found as scattered plants and new infestations in AL, GA, FL, SC, NC, and VA.
- Do not plant. Remove prior plantings, and control sprouts and seedlings. Bag and dispose of fruit in a dumpster or burn.
- Treat when new plants are young to prevent seed formation.
- Manual pulling is hindered by spiny leaflets.
- Manually pull new seedlings and tree wrench saplings when soil is moist, ensuring removal of all roots.
Recommended control procedures
- For stems too tall for foliar sprays, cut stems and immediately treat the stump tops with one of the following herbicides: Garlon 4, Garlon 3A, or a glyphosate herbicide as a 25-percent solution (3 quarts per 3-gallon mix). ORTHO Brush-B-Gon, Enforcer Brush Killer, and Vine-X are effective undiluted for treating cut-stumps and available in retail garden stores (safe to surrounding plants).
- Thoroughly wet all leaves with one of the following herbicides in water with a surfactant: a glyphosate herbicide or Garlon 3A as a 5-percent solution (20 ounces per 3-gallon mix) during the growing season above 70 °F (21 °C). When nontarget damage is not a concern, use one of the following herbicides: Arsenal AC* as a 0.12-percent solution (0.5 ounce per 3-gallon mix) or Arsenal PowerLine* as a 0.25-percent solution (1 ounce per 3-gallon mix) plus a glyphosate herbicide as a 2-percent solution (8 ounces per 3-gallon mix) plus Escort XP* at 0.4 dry ounce per 3-gallon mix in water. Spray as a low-volume application to lightly wet leaves.
* Nontarget plants may be killed or injured by root uptake.