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. Each berry has approximately 20 edible seeds that resemble tomato seeds based on their size and shape, but the seeds are not noticeable during chewing.

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.