Leptospermum scoparium manuka, New Zealand tea tree

Leptospermum scoparium, Science & Engineering Quad. Sairus Patel, 29 Apr 2019

James Cook’s “tea plant.” This looks like L. scoparium. Closely related Kunzea ericoides has much longer stamens relative to the petals, and flowers in clusters rather than singly. Plate XXII, Tea Plant of New Zealand. From James Cook’s A Voyage towards the South Pole, and Round the World, 1777

An unassuming shrub or small tree when not in flower, with small, prickly, almost needle-like leaves, and a certain severeness of habit whence presumably scoparium, meaning broomlike. The bright blossoms quite transform it in winter and spring: rounded petals surround a dark center fringed by short stamens. Flowers are usually white in the wild, though pink and reddish-pink forms, mostly from the far north of New Zealand, have given rise to a dazzling array of cultivars in saturated pinks and crimsons, including many with double flowers. Persistent woody capsules follow, holding narrow seeds (Leptospermum means slender seed).

A hand lens reveals dotted oil glands on the underside of leaves. During James Cook’s first voyages to New Zealand, aromatic leaves of what he called the “tea plant” were brewed as a tea substitute, perhaps as part of a broader effort to ward off scurvy. The illustration and description of the plant in his voyage account point only to what we call L. scoparium today; the closely related Kunzea ericoides has much longer stamens relative to the petals, and flowers in clusters rather than singly. The leaves were also added to a podocarp beer to cut its astringency, making the brew “exceedingly palatable, and esteemed by every one on board.” The name tea tree is also used for other myrtle-family plants.

‘Snow White’, with double white flowers, forms a hedge south of the Li Ka Shing Center, and has bloomed as early as mid-January. More are hedged on Campus Drive near the north corner of the Taube tennis pavilion. Two shrubby groupings of crimson, double-flowered ‘Ruby Glow’ can be found on Campus Drive near the south end of Manzanita Field; others once grew on the mound planting in front of the Shriram Center. The cultivar is one of many manuka cultivars selected in California. Another is ‘Helene Strybing’, with large single flowers of a deep pink; one is regenerating from a stump at 680 Salvatierra Street.

Pink and red tree forms can be seen in the faculty housing area, their bark peeling in long strips to good effect. A sizable specimen is at 691 Mirada Avenue; others are at 837 Cedro Way, 824 and 838 Tolman Drive, and 817 Pine Hill Road. A mounding groundcover, L. ‘Horizontalis’, has single white flowers and leaves shaped rather like those of the true myrtle; it grows at the Clock Tower.