They are not the hazels that produce the delicious edible nuts, but are in fact a relative of witch hazels, both being in the Hamamelidaceae family.
Waterfall effect
Flowers are the spectacular feature of Corylopsis and show at this time of year as small pendant racemes of fragrant lemon-yellow flowers, resembling catkins. Even though each flower is small, they appear en masse before leaves emerge, giving an overall yellow waterfall effect.
Woodland plant
This east Asian native will often form a multistemmed shrub to 3 metres in height and spread.
Propagation is easy, from seed or from semi-ripe cuttings in summer.
Corylopsis responds well to pruning, which means its height can be controlled. Pruning is best done immediately after flowering. With a fibrous root system they also respond well to pot culture and can be used for bonsai.
Whether in the ground or a pot, they prefer acidic moisture-retentive, but not waterlogged soil and a site in partial to full shade. Even though fully hardy, their wood is brittle so choose a sheltered site away from potential for heavy snow and strong winds.
Corylopsis species can be seen in the lower garden car park and in the north Asian border in the upper Botanic Garden near the junction of Lovelock Ave and Opoho Rd.
• Dylan Norfield is geographic and arboretum collection curator at Dunedin Botanic Garden.
