Melaleuca

Bottlebrush-like flowers, stiff leaves and peeling bark are all features of this exotic Australian native, says Miranda Kimberley.

M. alternifolia - image: Floramedia
M. alternifolia - image: Floramedia

For those looking for a touch of the exotic in their garden or conservatory, Melaleuca is well worth a punt. Similar in look to the better known Callistemon, with their bottlebrush-like flowers and stiff evergreen leaves, they are also known as the paperbarks for their peeling bark that can be colourful and even scented.

Sadly not everyone will be able to grow Melaleuca because they are Australian natives so can only be grown outside in the milder parts of the UK, doing particularly well on the coast and in sheltered gardens. They can, however, be grown in pots and kept as patio plants during the warmer months and then be brought into a greenhouse or conservatory when the frosts are due.

There are approximately 170 species of Melaleuca. Most are endemic to Australia but there are a few in parts of Malesia, which includes islands such as Borneo and the Philippines. They have several descriptive common names — the paperbark refers to the trees while the smaller forms are referred to as honey myrtles. M. alternifolia is known as tea tree, from which the popular oil is extracted.

Melaleuca are prized for their showy inflorescences, made up of clusters of small flowers with numerous stamens. These are usually brightly coloured in shades of red, pink, mauve, purple and yellow. They are united stamens that are bundled together before joining the floral tube, distinguishing them from Callistemon, which have free stamens.

While Melaleuca flowers are often arranged into a bottlebrush, they may also form a globular or irregular shape. Another nice feature is that after flowering, woody seed capsules develop and will persist on the plant, remaining tightly closed unless stimulated to open by fire or the death of the plant.

While most sources regard them as ranging from half-hardy to frost-tender, there are some species considered a little hardier — down to at least -5°C — and therefore worth a risk outside.

These include M. ericifolia and M. wilsonii. A specimen tree of M. ericifolia has been growing in the gardens at Tresco on the Scilly Isles since the 1980s and has survived periods of frost and snow. M. squamea is also considered tougher, hailing from the more southern island of Tasmania.

Some Melaleuca hail from parts of Australia where they grow in boggy conditions, but there are
also many species from the more Mediterranean climate of Western Australia that prefer well-drained conditions, so it is worth checking their place of origin if growing them.

Give them a position in full light. Water containerised specimens moderately, less during low temperatures. Be careful not to add too much fertiliser — they suffer with excessive nitrogen but slow-release fertiliser can be used. They can be regularly pruned to achieve a good shape and even respond well to hard pruning.

What the specialists say

Alasdair Moore, horticultural manager, Duchy of Cornwall Nursery

"It is commonly understood that for British gardens, except for those in the very mildest of climates, the Melaleuca is a plant that will need protection during the winter. For that reason, UK growers might be advised to grow them in pots and take them into a cool conservatory for the winter months.

"One common name for the Melaleuca is the paperbark, after the layers of thin bark that often cloak the stems. This bark, along with a lignotuber, can help the Melaleuca survive cold conditions as well as bush fires.

"For the really keen Australian-plant enthusiast wanting to grow Melaleuca outside, I would advise hardier species such as M. ericifolia and M. wilsonii. M. ericifolia, known as the swamp paperbark, will tolerate damp conditions and is considered one of the hardier species. In fact, a M. ericifolia tree survived days of frost and snow in Tresco on the Isles of Scilly in the 1980s and continues to flourish today. In terms of hardiness I would tend towards those species native to Tasmania such as M. squamea.

"In addition, I might look at something like M. squarrosa. Not only does it have attractive and scented flowers but it is also blessed with a lignotuber. My own favourite is M. diosmifolia, which I know from Tresco on the Isles of Scilly. It has beautiful clusters of green flowers and is a good coastal plant, but it won’t take a hard frost."

In practice

Ian Garland, owner, Grangehill Landscapes, London

"Melaleuca are not as well-known as their cousins the Callistemon, or even Grevillea or Banksia. They have quite small narrow leaves and in the garden centre, if they are not in flower, the buying public don’t have the impulse to take them home. But when the blooms do arrive they are in brilliant reds, purple and pinks, with their showy stamens.

"They are lovely conservatory plants that can be grown all year round, and if you are lucky enough to live in a southern coastal area you can take a chance on growing them outside, as long as they are offered a sheltered aspect."

Species and varieties

M. alternifolia is the source of tea tree oil, first extracted by the Aborigines to treat skin ailments. It has soft, linear leaves that give off tea tree scent when crushed and fluffy white bottlebrush flowers. Can be grown as a conservatory plant and sometimes used to create a bonsai tree. Minimum 2°C. Height: 3m.

M. armillaris, the bracelet honey myrtle, is an evergreen, rounded, wiry stemmed shrub or tree with needle-like deep-green leaves and dense white bottlebrush flowers in summer. Plants can withstand temperatures down to -5°C. Likely to be damaged or killed in cold winters. Height: 3-6m. Spread: 1.2-3m.

M. decussata is an evergreen shrub with papery bark and bottlebrush flowers that range from pink to purple or white and are produced in late spring to early summer. Can be regularly pruned to keep its compact shape. Height and spread: 3m.

M. diosmifolia is a tall half-hardy shrub that has crowded, spirally arranged oval leaves and beautiful green flowers. Plant can withstand temperatures down to -5°C. Can be grown in coastal and relatively mild parts of the UK but will suffer in severe winters and at risk from sudden early frosts. Height: 3m. Spread: 2m.

M. ericifolia, the swamp paperbark, is one of the hardier species. It is a tall, dense shrub or tree with pale-white or brownish papery bark. Its leaves are linear and dark-green, arranged alternately or sometimes in whorls of three. It produces plenty of creamy white bottlebrush-like inflorescences. A specimen tree has been growing in Tresco on the Isles of Scilly since the 1980s. Height: 6-12m.

M. gibbosa is a densely spreading shrub that produces masses of dainty mauve-coloured bottlebrush flowers in summer. Probably best treated as a patio plant during the summer so that the pot can be brought in over winter. Height: possibly 2m.

M. linariifolia, or snow-in-summer, is a fast-growing small-to-medium tree with attractive foliage and a bushy habit. White paper-like bark produces fluffy creamy white flowers in summer. Height: 8m.

M. squamea, the swamp myrtle, is an evergreen, upright shrub with narrow aromatic foliage and small pink/purple bottlebrush flowers in summer. Best in moist, well-drained soil in full sun. A good coastal plant. The minimum temperature it will cope with is -5°C, so it needs shelter in cold areas. Height: 1-2m.

M. squarrosa is a dense, upright, evergreen shrub or small tree with tiny ovate dark-green leaves and long spikes of lightly fragrant, creamy yellow flowers in late spring and summer. Frost-tender, slightly hardier than other species. Height: 3-6m. Spread: 2-4m.

Thank you to Floramedia, which supplied the images for this article from its photo library
www.floramedia-picture-library.com


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