Eucalyptus robusta aka Swamp Messmate

Eucalyptus robusta, or swamp mahogany, is an evergreen tree. It belongs to the myrtle family, Myrtaceae. Its native range runs from southeast Queensland to eastern New South Wales. It grows near coastal rivers, lagoons, and swamps. These sites flood from time to time. People now grow it across many warm parts of the world.

Trees usually reach 82–98 feet [25–30 metres] tall. Their spread can reach about 66 feet [20 metres]. Planted giants in Hawaii have reached 180 feet [55 metres]. Growth is fast, and trees can live for 200 years or more. The trunk tends to be straight. It often lacks branches along its lower half. Open-grown trees form dense crowns with long, spreading branches. These branches can be brittle and grow in uneven shapes. Crowded trees have more upright branches and narrower crowns.

The thick, reddish-brown bark has a spongy texture. Broad, dark green leaves stay on the tree year-round. White or cream flowers grow in clusters. Bees and other insects pollinate them. The tree also forms seed capsules. In humid plantations, some trees grow roots from their trunks. These aerial roots can start 20 feet [6 metres] above ground.

Swamp mahogany grows in sun and tolerates light shade. It accepts sandy, loamy, and clay soils. It also grows across mildly acid to mildly alkaline conditions. PFAF lists dry or moist soil and a preference for drainage. Its natural habitat also shows that it tolerates periodic flooding. It suits subtropical climates but can adapt to warmer regions. It withstands light frost, though severe frost limits its range. PFAF lists USDA zones 8–12.

Growers plant this tree for timber, shelter, and ornamental use. Its wood supplies fuel, charcoal, fencing, and furniture. Plantings can help restore woodland and hold dunes in place. Trees stand up to wind, but constant exposure can distort them. Salt spray is a limit on coastal use. Both plant databases flag weed potential. PFAF gives it no food value and lists no known edible use. It records traditional leaf remedies for fever and breathing complaints. These records do not establish safe or effective treatment. Useful Tropical Plants reports no known hazards for this species. The supplied evidence does not establish its safety for pets.