Are Eucalyptus and Melaleuca Related?
Both eucalyptus (Eucalyptus spp.) , hardy in U.S. Department of Agriculture plant hardiness zones 7 to 11, depending on cultivar, and melaleuca (Melaleuca spp.) Hardy in zones 8 through 11, depending on cultivar, include evergreen shrubs and trees native primarily to Australia — and they are associated. They belong to the myrtle familymembers, or Myrtaceae, and share the characteristic of fragrant leaves which have pungent oils. Their flowers have a similar structure, with often showy color that comes from long stamens rather than petals. Varieties of the Melaleuca and Eucalyptus are grown as garden plants in warm winter areas of the USA.
Development Habits
Melaleuca and eucalyptus have similar growth habits. The Melaleuca species contains about 200 shrubs and small trees. The trees are called paperbark due to their white, peeling bark. The shrubs are called honey myrtle according to their plentiful flower nectar. Melaleucas rise in open woodlands and together with water. Eucalyptus includes mainly trees and shrubby species known as mallees. Over 900 eucalyptus varieties grow throughout Australia, except at high alpine areas, many with peeling bark. They are the dominant forest trees, and also their high-crowned canopies are symbols of Australia. Mallees predominate in the arid shrub lands of Western Australia. Both eucalyptus and melaleuca have woody seed capsules and tiny, fine seeds.
Leaf Chemicals
Crush a leathery, often stiff leaf of melaleuca or eucalyptus and you’ll release noticeable aromasthat can be different depending on the species. Lemon-scented gum (Eucalyptus citriodora), hardy in USDA zones 9 through 11, has a powerful lemon smell. Nichol’s willowleaf peppermint (Eucalyptus nicholii) smells of mint and rises in USDA zones 9 through 11. Both melaleuca and eucalyptus are commercial sources of essential oils. Tea tree oil comes from tea tree (Melaleuca alternifolia), hardy in USDA zones 8 through 11. Eucalyptus oils, used in fragrances, industry and in medicine, come out of numerous eucalyptus species.
Garden Use
In their native habitats, eucalyptus and melaleuca supply nectar for birds and small marsupials such as honey-eaters. In U.S. gardens, they attract butterflies and hummingbirds. Both groups of plants provide scented leaves and aromatic, often showy flowers. A good example is pink bottlebrush (Melaleuca nesophila), also a drought-tolerant bush to little tree appropriate for coastal gardens. It can produce pink, purple or purple flowers at any given season in clusters at branch ends, growing in USDA zones 9 through 11. Melaleuca leaves are usually green, however, shrubby eucalyptus frequently have interesting leaf shapes and colours. Eucalyptus flowers are generally bell-shaped with a cup-like woody base. Lots of little- to medium-sized eucalyptus tree species furnish garden forks or accents. A good example is coral gum (Eucalyptus torquata), with big coral-pink flowers, growing in USDA zones 9 through 11.
Garden Culture
Because so much of Australia is arid, many melaleucas and eucalyptus are drought-tolerant, needing well-drained soil and full sunlight. Mallees benefit from pruning back to ground level every 10 decades. Eucalyptus trees require shaping while they are young, but require little maintenance once established. Few eucalyptus will increase out of gardens, with the exception of red river gum (Eucalyptus camaldulensis), hardy in USDA zones 9 and 10. Introduced to arid lands throughout the world as a forestry, shade and windbreak tree, red river gum is dangerous in some places. One melaleuca, river tea tree (Melaleuca quinquenervia), growing in USDA zones 9 through 11, additionally has invasive potential.