Haskap is a deciduous shrub growing to 1.5–2 m (4 ft 11 in – 6 ft 7 in) tall. The leaves are opposite, oval, 3–8 cm (1.2–3.1 in) long and 1–3 cm (0.39–1.18 in) broad, greyish green, with a slightly waxy texture. The flowers are yellowish-white, 12–16 mm long, with five equal lobes; they are produced in pairs on the shoots. The fruit is an edible, blue berry, somewhat rectangular in shape weighing 1.3 to 2.2 grams (0.046 to 0.078 oz), and about 1 cm (0.39 in) in diameter.

The plant is winter-hardy and can tolerate temperatures below −47 °C (−53 °F). Its flowers are frost-tolerant. Fruits mature early and are high in vitamin C.

Haskap cultivars can survive a large range of soil acidity from 3.9-7.7 (optimum 5.5-6.5), requiring high organic matter, well drained soils, and plentiful sunlight for optimum productivity. Lonicera caerulea plants are more tolerant of wet conditions than most fruit species.