Mentor Barberry

(Berberidaceae - Barberry Family)

Form

• medium-sized foliage shrub
• maturing at about 6' tall by 6' wide, if not pruned or sheared to a smaller dimension
• upright rounded to upright spreading growth habit
• slow growth rate

Culture

• full sun to partial sun
• performs best in moist, well-drained soils, but is very tolerant of various soils, soil pHs, soil compaction, drought, heat, pruning, and pollution
• propagated primarily by rooted stem cuttings
• Barberry Family, with few diseases or pests
• low availability, in ball and burlap or container form
• Mentor Barberry is somewhat sensitive to being transplanted in Autumn, and care should be taken to amend the soil, fertilize, water thoroughly, mulch adequately, and avoid Winter salt spray, to enhance survival chances during the first Winter

Foliage

• new foliage emerges chartreuse, but turns dark green or blue-green by Summer
• semi-evergreen to slowly deciduous leaves are 1" to 2" long, alternate, elliptical, with a cuneate base, no petiole, and have short spines on the mature leaf margins
• fall color is yellow to wine-colored in late Autumn and early Winter

Flowers

• yellow, in late April to early May, in pendulous clusters that hang directly from the stems
• not showy, yet attractive when viewed close-up, and attracting many bees

Fruits

• usually not present, and ornamentally insignificant when present

Twigs

• transition from yellow-green to red to brown stems with maturity, being lightly grooved, with small, scaly buds
• prominent spines are one-, two-, or three-pointed and numerous along the stems
• stems, branches, and roots are slightly brittle and sometimes broken when bent or transplanted, revealing a bright yellow interior wood

Trunk

• not applicable

ID Summary

• alternate, elliptical leaves with no petiole and sparse spines along the margins emerges chartruese, transitions to dark green or blue-green, and often ends up as a marginally effective green-wine late fall color, being semi-evergreen in mild Winters
• small yellow flowers occur in pendulous clusters from the previous year's wood, noticeable but ornamentally insignificant, but attracting many bees
• relatively thick stems and branches have one-, two-, or three-pointed spines, unlike Japanese Barberry, which has single spines covering its twigs

USAGE

Function

• formal hedge, informal hedge, thorny barrier hedge, wildlife refuge shrub, or group planting shrub

Texture

• medium texture when in foliage, semi-evergreen, or bare
• thick density in foliage and when bare

Assets

• good urban stress-tolerant shrub that takes well to shearing
• prominent spines (if they are desired) serve as an effective deterrent
• foliage and stems typically extend all the way to the ground (a desirable trait for a formal hedge)
• small bird refuge; Birds love to have dense, thorny shrubs or trees in which to pause during their daily activities of flight and feeding, or to nest, since the dense twigs and thorns protect them from sudden attack by natural enemies, such as cats. Mentor Barberry is therefore a logical shrub that, when left unpruned in its natural form, is an excellent complement to larger thorny (Crataegus crus-galli, Crataegus phaenopyrum, Rosa multiflora, etc.) or spur-shoot laden (Malus sargentii, Photinia villosa, Viburnum prunifolium, etc.) shrubs and trees in areas where bird feeding or general bird attraction is desired.

Liabilities

• prominent spines (if they are not desired), which can cause injury and pain
• garbage and leaf collector (at the base of the spiny-stemmed shrub)

Habitat

• zones 5 to 8
• a hybrid of Wintergreen Barberry (Berberis julianae, native to China) and Japanese Barberry (Berberis thunbergii, native to Japan), hybridized in Mentor, Ohio (hence the common name)

SELECTIONS

Alternates

• other thorny or spiny shrubs serving as hedges or barriers (Acanthopanax sieboldianus, Berberis thunbergii, Rosa rugosa, etc.)

Variants

• selections of the hybrid Berberis x mentorensis apparently do not exist; however, a listing of the parents of Mentor Barberry and their general characteristics follows:
• Berberis julianae - Wintergreen Barberry - broadleaf evergreen, lustrous dark green foliage becomes bronzed in Winter, but may die and remain on the stems in Winter if the shrub is in an exposed site; prominent marginal tripartite spines to 1" long each; blue-black fruits in Autumn; maturing at 8' tall by 8' wide; zones 5 to 8
• Berberis thunbergii - Japanese Barberry - slowly deciduous small foliage; thin stems with single spines; small ellipsoid red winter-persistent fruits on mature shrubs; species form at 5' tall by 5' wide, but found abundantly in the landscape as cultivars that are bright green, gold, maroon, or variegated, and often smaller; zones 4 to 8

NOTES

Translation

• Berberis is the Arabic name for Barberry fruit.
• x mentorensis recognizes Mentor, Ohio where it originated from the hybridization of Wintergreen Barberry and Japanese Barberry.

Purpose

• Mentor Barberry is a very effective shrub when utilized as a thorny barrier hedge (either sheared or unpruned) or in an informal mass planting.

Summary

• Berberis x mentorensis is a tough, urban-tolerant shrub or hedge with dense foliage and prominent spines, normally used as a barrier hedge or in group plantings, but can also be planted as an unpruned solitary shrub for uses such as a small bird refuge.