Berberis x gladwynensis William Penn

Gladwyn Barberry, William Penn Barberry

Berberis × gladwynensis ‘William Penn’ — commonly known as William Penn Barberry — is a semi-evergreen to evergreen barberry valued for its glossy, dark green foliage, dense branching, and excellent performance as a formal or informal hedge. Unlike Japanese barberry, this hybrid offers a cleaner look with fewer invasive concerns and a more refined, boxwood-like appearance.

Clusters of small yellow flowers appear in spring, followed by blue-black berries that add seasonal interest.

Key features
Width / spread: 4–6 ft
Height: 5–7 ft
Foliage: Glossy dark green; semi-evergreen to evergreen
Flower color: Yellow (spring)
Fruit: Blue-black berries (fall)
Form: Dense, upright to rounded shrub
Life cycle: Semi-evergreen shrub

Growing conditions
Sun: Full sun to part shade
Soil: Well-drained; adaptable to a range of soils
Water: Moderate; drought tolerant once established
Hardiness:



Zone Low: 6a



Zone High: 9a



Landscape use
Formal and informal hedges
Screens and boundary plantings
Foundation plantings
Mixed shrub borders
Security plantings (thorny stems)

Notes
Excellent substitute for boxwood in warmer climates
Denser and glossier than most deciduous barberries
Spiny stems provide deer resistance and security value
Responds very well to pruning and shearing
Less invasive concern than Berberis thunbergii

Plant type

Deciduous Shrub

Height

5-7'

Width

4-6'

Hardiness zones

6–9

Sunlight

Full Sun

Growth rate

Moderate

Bloom time

Spring

Flower color

Yellow

Leaf color

Dark Green

Fall color

Bronze

Attracts

Butterflies

Soil

Clay, Loamy, Normal

Landscape use

Foundation

Shape

Broad Upright

Bark

Smooth

Fruit

Yes

Fragrant

Yes

Deer resistant

Yes

Drought tolerant

Yes