Growing Vireya Rhododendrons in Coastal California
By Tyson Curtis in Partnership with Flora Grubb Gardens
It’s well known that at Flora Grubb Gardens we love epiphytic forest dwellers. Epiphytes are plants that grow on trees such as bromeliads, orchids, staghorn ferns, rhipsalis… and vireyas!
Vireya are rhododendron and azalea relatives from southeastern Asia, growing from eastern India through Malaysia and down into Northern Australia. There are hundreds of species and even more hybrids, all grown for their umbels of trumpet-shaped or bell-shaped flowers. Vireyas bloom from white into warm tones. Many are sweetly fragrant. The size of both plants and flowers vary dramatically by selection, from the miniature Vireya ‘Little Bo Peep,’ with quarter-sized flowers on a tabletop-sized plant, all the way up to Vireya macgregoriae, which can grow to fifteen feet tall.
Since vireyas only thrive in a thin strip along our California coast, they are rarely grown in production and quite hard to find. Our Flora Grubb buyers have long been cultivating relationships with mom-and-pop growers, who provide the vireyas we carry. Vireya are almost always in stock at our retail nurseries in San Francisco and LA.
Vireya are cool-growing tropical plants, requiring similar care to other epiphytic orchids and cactus: good drainage, frequent watering, bright dappled light, and a lightly acidic medium.
In habitat, Vireya grow at higher altitudes where temperatures are mild. This makes them a durable element for cool weather gardens with marine influence. Their flowers arrive when temperatures drop in fall and re-bloom through spring. Deadheading encourages repeat flowering. They also respond well to a yearly pruning to maintain their size or shape. They do not grow well in cold or hot areas, such as the inland zones of California. Vireya will take a light frost with a bit of damage, but not much more. They love humidity and resent dry winds.
Surprisingly, these plants do well indoors and can be moved in when winter temperatures are severe and later be returned to a mild summer outdoors. With fragrant cultivars, this brings the wafting perfume of a tropical mountainside inside your home. Vireya perform well in Sunset Zones 16,17, 20, 21, 23 and 24. If you live near one of our retail stores in San Francisco or Marina del Rey, you are probably in one of these zones!
Their natural habit of growing in the cracks of trees makes Vireya amazing choices for pots, even very small ones, and in fact they prefer to be a bit rootbound. They're right at home in living walls or even mounted on a tree or rock, making them a great plant for urban gardens without much space. Vireyas love terra cotta pots that allow their roots to breathe. In pots we grow vireya in orchid or cactus mix. Many vireyas also grow terrestrially in nature; to grow yours in the ground, amend heavily with pumice or lava rock to add adequate drainage.
Lovely vireyas get passing tropical showers, but also dry out in the days between, due to their quick draining medium. Water your Vireya when it is mostly dry, but never let it dry out completely. If the medium is well-drained it is safer to overwater than underwater. Give more water during budding and blooming, in winter, and then dial back in summer.
Imagine your Vireya is growing in a treetop in Borneo. It may have a splash of direct sun bathing the plant for an hour or two, but most of its day is spent with dappled light filtering across its leaves. A similar exposure in your garden will make your plant feel at home.
These wonderful plants are fed by decomposing leaf litter in nature. This creates a mildly acidic environment. Many of our customers report that their plants thrive and bloom without additional feeding, but vireyas will appreciate a light acidic fertilizer such as cotton seed meal or diluted liquid acid fertilizer.