Leptospermum lanigerum Karo Silver Ice

Leptospermum 'Karo Silver Ice' is a hybrid variety of tea tree, quite recent, forming a large bush that appears to be covered in silvery snow. It owes this to its abundant and long-lasting white flowering period, composed of a multitude of small immaculate white cup-shaped flowers, and its grey-green foliage abundantly covered with silvery bristles. The ensemble is remarkably bright. This evergreen bush is cultivated in open ground in a mild climate, in well-drained soil, not too chalky to acidic, including by the sea. It accepts pot cultivation very well, to be stored over winter in colder regions.

Leptospermum 'Karo Silver Ice' is a horticultural creation dating from the mid-1980s. It is the result of cross-breeding the L. rotundifolium ‘Jervis Bay’ and L. lanigerum var. lanigerum. Leptospermum are cousins of Mediterranean myrtles, clove trees and Eucalyptus. All from the Myrtaceae family, they share a love of heat and a tolerance to dry and poor soils. With a bushy, dense and spreading habit, it will reach an average of 1.5 m (5 ft) in all directions, but sometimes up to 2 m (6.5 ft) if the growing conditions are optimal. It is provided with alternate, single, rounded leaves, small in size, white at bud burst, later taking on a green hue somewhat masked by numerous silvery bristles. The ensemble of the foliage displays a silver-green colour. The flowers, single, honey producing and rich in nectar, appear for 5 to 6 weeks from April to June in warmer climates, later in colder regions. They are composed of 5 white petals surrounding a green heart and can reach 3 to 4 cm (1.2 to 1.6 in) in diameter. They are followed by small capsules releasing thin elongated seeds. This bush can be lightly pruned after flowering, from May to July.

The 'Karo Silver Ice' tea tree withstands temperatures down to -10°C (14 °F) but the aerial parts can be damaged from -6°C (21.2 °F). It should be placed in a sheltered spot, in full but not scorching sun. It tolerates sea spray well, making it a very beautiful bush for seaside gardens. While it prefers neutral to acidic soils, it also tolerates clay-limestone soils according to some experts, provided they are light, loamy and correctly drained. 

In a flowerbed or border it can be combined with other Australian or New Zealand shrubs such as Callistemon, Grevillea, Melaleuca, but also with South African species: Gomphostigma 'White Candy', Dierama, Aloe arborescens, Anisodontea capensis or Melianthus major should thrive in the same growing conditions. It can also be used in the creation of a medium-sized evergreen hedge (max. 2 m (6.5 ft) tall) in the company of Myrtles, large cistus (Cistus laurifolius, Citus (x) aguilari), Feijoa, or Olearia. In regions with very cold winters this plant should be cultivated in a pot and kept frost-free throughout the winter.

Leptospermum means "thin seed" and gets its common English name of tea tree from Captain Cook and his crew, who used its leaves to prevent scurvy.