That age-old problem of several plants having the same or
similar common names holds true for those species of plants known
as “tea tree.” One plant that is sold under the common name
Australian tea tree in California is Leptospermum laevigatum. In
Australia, this species is also known by the common names
Australian myrtle, coast tea tree, and Victorian tea tree. It grows
in much of the southern part of Australia (in the states of
Victoria, South Australia, and Tasmania) in dry forests along the
coast, where it forms dense thickets of twisted, sculptural trunks
topped with evergreen foliage. Small white flowers cover the whole
tree in the spring. As a garden subject, this Australian tea tree
is a tough cookie. It is suitable as a single specimen or planted
as a hedge. Ultimate heights of 15 feet or more may be expected,
but shearing and pruning can keep it much more manageable. One of
its fine qualities for use in our coastal zone is its resistance to
salt spray. Plant it right down to the beach and it should
thrive.
Leptospermum scoparium is also known as tea tree, tea bush, or
manuka by the native New Zealanders. While it grows in southern
Australia as well as New Zealand, it was in New Zealand that
Captain Cook gave it the name tea tree. He remarked that “the
leaves … were used by many of us as tea, which has a very agreeable
bitter[ness] and flavor, when they are recent, but loses some of
both when they are dried. When the infusion was made strong, it
proved emetic to some in the same manner as green tea.” Manuka was
used in pre-European times by the traditional people of New
Zealand, the Maori, and still is. A decoction of the leaves was
drunk for urinary complaints and as a cure for intestinal
parasites. The steam from leaves boiled in water was inhaled for
head colds. A decoction was prepared from the leaves and bark, and
the warm liquid was rubbed on stiff muscles and aching joints. The
emollient white gum, called pai manuka, was given to nursing babies
and also used to treat scalds and burns. Chewing the bark is said
to have a relaxing effect and it enhances sleep.
New Zealand tea tree oil has been on the market since 1993. Most
of the material is from the East Cape region of the North Island of
New Zealand, although populations from various locations produce
potions with discernable chemical differences. The East Cape oil
has the strongest antibacterial action. In fact, New Zealand tea
tree oil is reported to be as much as 20 times more effective as an
antibacterial agent than Australian tea tree oil (see below).
Normally growing to 10 feet or less, this shrubby cousin displays
some variety in form. Its small flowers may range from cranberry
red to pink to white, with double forms also available. Some
selections also have bronzy foliage for further interest. It will
do best with well-draining soils, but once established should
provide lots of good color for much of the year. Its extra gift to
the landscaper is that it will flourish in shade.
Melaleuca alternifolia is also from Australia and is also called
Australian tea tree. Though tea is in its common name, an infusion
of its leaves is a poor substitute for potable tea. And due to some
of its chemical components, may even be toxic if consumed in
quantity. It is, however, the source of an essential oil that is
widely marketed as an antibacterial and skin treatment. This tea
tree oil got its name from the British explorers who observed the
Aborigines brewing leaves of the tree to make a tea that was used
to cure various ailments. For many centuries, the Australian
Bundjalung Aborigines bathed in the healing waters of swampy areas
where the Melaleuca alternifolia plants grew. They also
successfully treated skin conditions by crushing the leaves and
spreading the pulp over the affected area.
Another common name for this species is snow in summer (another
name applied to more than one species!), which aptly describes the
effect of its many bright white bottle-brush-type inflorescences
that cover the shrub in summer. It, too, is an evergreen that grows
more shrublike than treelike to about 18 feet. Because this tea
tree is native to saturated soils, it can take that sort of
treatment in the garden, too. It takes poor drainage in stride and
hates drought.
As with any plants that have herbal or medicinal properties,
grow them for their beauty, but be cautious if you use them for any
other purpose.
Virginia Hayes, curator of Ganna Walska Lotusland, will
answer your gardening questions. Address them to Gardens, The
Independent, 122 W. Figueroa St., S.B., CA 93101. Send email to
vahayes@lotusland.org.