Warty barberry

Synonyms: Berberis verruculosa, tuberous barberry, small-warty barberry

Warty barberry – a species of barberry from the genus Berberis (Berberis) of the family Berberidaceae. Native to western China (Gansu, Sichuan, Yunnan). In cultivation since 1904. The species has received the Award of Garden Merit (AGM) of the English horticultural society.

It is an evergreen shrub 1–1.5 m high and up to 1.5 m in diameter with a rounded or broadly upright crown. It grows slowly. Branches are directed vertically upward and arch at the tips, stiff, brown. Shoots are yellow-brown, cylindrical, densely hairy and covered with a large number of warts, which gave the species its name.

Thorns up to 2 cm long, single or divided into 2 or 3 parts, narrow.

Root system superficial, well branched, with a large number of fine roots.

Leaves alternate, up to 2.5 cm long and 1.2 cm wide, elliptic or obovate, with an acute tip and finely serrated margin, with 2–4 thin spiny teeth on each side. Above the leaves are green, glossy; beneath they are covered with a waxy coating, bluish-gray, leathery, stiff, with almost no veins. In autumn they turn bright red, after frosts they acquire a bronze tint.

Flowers in May–June. Flowers small, 1–2 cm in diameter, golden-yellow, borne singly or in pairs. Pedicels 0.4–0.8 cm long.

Fruits ovoid or pyriform, 1 cm long and 0.8 cm wide, purplish-black with a bluish waxy bloom, without a style.

Cultivars: Berberis verruculosa 'Apricot Queen'.

Hardiness zone: 4 (-29°C). May suffer some frost damage in severe winters.

Location: winter-hardy, drought-tolerant. Undemanding. Grows well on dry and sandy soils. Prefers acidic or slightly alkaline soil. Does not tolerate waterlogging. Light-loving but shade-tolerant. Tolerates urban conditions well, wind-resistant.

Planting: best carried out in spring or autumn. If soil pH is above 7, liming is recommended. Planting mix: peat, topsoil, humus, 400 g slaked lime (if pH>7) and 200 g wood ash. Planting hole size: 40×40 cm. For single planting, spacing between plants should be 1.5–2 m. For creating a hedge, prepare a trench and place shrubs at a rate of 2 shrubs per linear meter.

Care: care consists of shallow cultivation of the root circles and mulching. Watering is recommended at least once a week with 2–3 buckets per plant. In spring, one year after planting, nitrogen fertilizers may be applied. Further nitrogen feeding should not be done earlier than every 3–4 years.

Pruning: tolerates clipping well.

Propagation: spring-sown seeds require stratification at 1–5°C for 3–4 months. Seeds can also be sown in autumn without stratification immediately after harvest or cleaned of pulp. Sowing depth 2–3 cm. Rooting of summer cuttings 80–90%. Seed viability 92%.

Diseases: bacterial canker, powdery mildew, Septoria leaf spot, infectious branch dieback, Phyllosticta leaf spot, leaf spot. Not affected by rust.

Pests: barberry aphid, barberry sawfly, barberry fruit moth, leaf-eating insects.

Uses: Good honey plant. In landscape design used in solitary plantings, in landscape compositions, and also as a border plant.