Metrosideros is a genus belonging to the Myrtaceae family that contains around 50 species of vines, trees, and shrubs. Some species of Metrosideros are popular in cultivation due to having flowers that are considered attractive. Plants in this genus are native to Pacific islands such as New Zealand and the Philippines, as well as a few others. The seeds of these plants can propagate through the air, and the coloring of their flowers is fairly diverse, ranging from red and orange all the way to white.
As of 2010, only 34 adult trees of Metrosideros bartlettii are known to exist in the wild. This rare tree has notable white flowers, a bit of an aberration among its genus. In cultivation, these trees can grow from hardwood cuttings and fresh seed, though they grow more easily from seed. John Barlett, a school teacher from New Zealand, discovered this tree in 1975. The whitish-grey bark of the tree is believed to be somewhat resistant to fire; this is speculated to have something to do with its survival in regions subject to forest fires.
Metrosideros excelsa, one of the species in this genus that is native to New Zealand, is notable for its ability to thrive on rocky cliffs. These trees used to be so common on New Zealand that they could be spotted continuously along some coasts. However, their populations were damaged considerably in the 1990s by farming and invasive pests. This plant is also known as the New Zealand Christmas tree due to its crimson flowers that peak in bloom during December. As of 2010, this tree is even further threatened by the common brushtail possum that was introduced from Australia.
Another tree endemic to New Zealand, Metrosideros umbellata, typically has scarlet flowers, though it can also have yellow and white ones. This tree thrives in a region with regular rainfall and a cool climate. It has sharply pointed leaves and occasionally grows as an epiphyte. In cultivation, it is important that it is grown in its ideal climate, with close attention paid toward keeping its soil moist. This plant does well in coastal regions, showing good resistance to the pressures of salt and wind.
Due to this genus’s popularity, there are many cultivars or varieties available. These names, such as Metrosideros vitiensis and Metrosideros villosa, are frequently confused for actual species. Horticultural catalogs and other reputable sources have also made this mistake, further adding to the confusion.