Myrtaceae, the Myrtle Family
This is a well-branched shrub growing to 6 feet tall. The glossy, leathery evergreen leaves have three conspicuous main veins, and they are usually densely hairy on the underside with gray or tawny hairs, but occasionally, plants have leaves which are nearly glabrous (without hairs). The leaves are oval in shape, blunt at the apex, and 2 to 3 inches long. The flowers are about 1 inch across, and they are borne singly or a few together in the axils of the leaves. Flowers have five rose-pink petals and a central mass of numerous pink stamens. The juicy berry is about a 1/2 inch across, and it turns dark purple when ripe, strongly resembling a blueberry in shape.
The downy myrtle is native to southern and southeastern Asia, from India to the Philippines and Indonesia, where it grows in a variety of habitats from sea level to 7,000 feet elevation. It has been introduced into the Pacific Islands where it has become seriously invasive. In the United States, it has only been recorded from Florida and Hawaii.
This species has invaded a variety of plant communities, including scrub, coastal strands and flatwoods in scattered counties, from Central Florida to Collier and Palm Beach counties in the south.
Another species in the Myrtaceae, the pineapple guava (Acca sellowiana) has similar flowers and foliage. However, the leaves of this commonly cultivated plant are whitish beneath, at least when young, and they are not three-nerved. Pineapple guava flowers have four fleshy, edible petals that are cupped and somewhat reflexed, accentuating the central mass of stiff, dark red stamens. A native plant in the Melastome Family, Tetrazygia bicolor, the Florida clover ash, has opposite, three-nerved leaves that are tomentose beneath, but its flowers are white and are borne in terminal panicles.
The fleshy berries are eaten by various fruit-eating species of birds and mammals, which then disperse the seeds widely. Each fruit contains as many as 200 small seeds, and these germinate readily. Evidently the plants do not spread by suckers or other vegetative means.
This is an attractive ornamental, and the fleshy fruits are sweet and edible and can be made into jams and pies. It was introduced into Florida in the 1920s, where it soon escaped and rapidly became a serious pest. It is fire-resistant, resprouting rapidly after being burned, and it forms dense stands in pinelands and other habitats, mostly in the central part of the state. Downy myrtle is included on Florida's noxious weed list, and it is also listed as a Category I invasive by the Florida Exotic Pest Plant Council (FLEPPC). University of Florida/IFAS staff warn that this species has the potential to become a more serious invasive threat in Central Florida than Brazilian pepper (Schinus terebinthifolia).