Other Names: Bamboo Orchid
Arundina graminifolia is more commonly called the Bamboo Orchid due to its grassy, reed-like foliage and its large clumps of bright, showy flowers.
This tropical orchid is a favorite ornamental flower in its native Hawaii. You'll also find it growing wild in Nepal, Thailand, Sri Lanka, Vietnam, China, and Indonesia.
The reedy stems on this orchid give way to large clusters of up to ten flowers on a single stem. It'll grow to heights that range between 70 centimeters and 2 meters with the long, thin, leaves spreading out from 9 to 19 centimeters. The orchid blooms in late summer to early autumn and the flowers are 5 to 8 centimeters in diameter and feature a bright, lilac hue with a white disk.
As this orchid comes from tropical regions, you'll need to maintain a daytime temperature between 70°F to 85°F (21°C to 29°C) during the summer months from March to October. During the nighttime hours, the temperature shouldn't go below 60°F (15°C), and the closer it stays to the low 70s, the better it is for your plant.
During the winter months between November and February, you can keep your orchid in slightly lower daytime temperatures around 61°F (16°C) with nighttime temperatures around 50°F (10°C). This is when your orchid will go dormant.
Arundina graminifolia does very well in sunny locations, but don't put it in direct sunlight as the leaves can burn due to the higher humidity and moisture levels. You can diffuse the level of sunlight your orchid gets by placing it slightly away from windows. It'll still get a lot of sunlight, but it won't be the hot, direct sunlight you have to worry about.
Water and Humidity
At the start of the growing season from March until June, you should water your orchid sparingly until you start to see buds and signs that it's growing. When you see these, you can start to water it weekly and spritz it between watering to keep it moist until October.
Once October starts, your orchid will start to go dormant, and when it goes completely dormant, stop watering it until it starts to flower again in mid-February or early March.
You also want to maintain higher humidity levels during the early growth stages through the growing season. You should have your humidity levels between 65% to 75% to ensure optimal growth. You can reduce the humidity level slightly when it goes dormant.
You can feed your orchid from March until October when it is in active growth. You should feed your orchid once every two weeks with a quarter of a packet of high-nitrogen fertilizer that you've diluted to half strength until it reaches its dormant period. Don't feed it while it's dormant.
Your Arundina graminifolia is epiphytic, and this means it grows well mounted on bark, in a pot, or in a hanging basket. You'll want to refresh their potting medium every two to three years, and it's best to repot your bamboo orchid in the springtime.
When you've removed it from the pot, cut away any dead or dying roots. You can repot it back into the original container with fresh compost mixed around its roots. Water it sparingly for six weeks to help it reestablish itself, and don't bury the roots completely as they do better when they're semi-exposed to the air and sunlight. You may also want to stake it if it's top-heavy to prevent breakage.
See the Arundina Graminifolia growing in a garden alongside herbs like basil and thyme.