Starting this weekend, Saturday Oct. 21, the Hawaii Chapter of the American Rhododendron Society is having a tropical vireya outreach at the Pana‘ewa Zoo. Members will be there from 10 a.m. until 2 p.m. to share their knowledge and plants with the public. There is also a vireya garden you may visit at any time at the zoo. For further information call Sherla Berttelmann at (808) 966-9225.
The following Saturday, Oct. 28, from 8 a.m. to 1 p.m. you can meet local growers at the Old Kona Airport for expert gardening advice. According to Bob Harris, event organizer of the ninth Plant People Road Show, nursery folks will be there to answer all the questions you have about gardening. A remarkable variety of common and rare plants will be available as well. Look for native, canoe plants and exotics of all sorts at this one stop shop event.
Master Gardener Gary Kastle just announced the Arbor Day giveaway from 8:30 a.m. to 12 noon on Saturday, Nov. 4 in Ocean View. The location will be next to the Ocean View Swap meet beside the Malama Market grocery store. Master gardeners will be there answer gardening questions. They will also give away native and non-native plants. Call the UHCTAHR Master Gardener Helpline at (808) 322-4893 for details.
Now back to the Plant People Road Show. There will be all kinds of goodies but in particular look for all the exciting orchids. At one time, the island of Hawaii was known as the Orchid Isle due to the commercial production of vanda and dendrobium orchids. Wild bamboo orchids and Malayan ground orchids grew and still grow prolifically in open meadows. The understory of mauka forests to this day are filled with Phaius tankervilleae, or Chinese ground orchids. Fancy varieties of these naturalized species are now being grown by orchid enthusiasts.
There are many orchid species and hybrids that are easy to grow in Hawaii. Orchids are well adapted here and many species need almost no care. Epidendrum radicans, along with the new epi-cats (epidendrum and cattleya), with their attractive pastel shades are becoming quite popular as houseplants and outdoor plantings. Epidendrums produce thin, reed-like foliage with many aerial roots. Tip cuttings with a few serial roots may be potted to increase the numbers of this plant. Flowers are one inch or less in size but are produced in great numbers. They are very effective for arrangements as well as for corsages.
Oncidiums are among the most valuable of the spray orchids. They are commonly referred to as dancing girls or popcorn orchids because of their shape. Flowers come in yellow and brown, white and brown, and other similar color combinations. They may attain sizes of 1/2 to 3 inches across. Many flowers may be produced on a single flower spike.
Strap-leafed vandas have become very popular with growers and hobbyists. The wide range of colors, from blues to orchids to brown to whites, have attributed greatly to its popularity. Vanda flowers are long lasting and excellent for corsages. Each flower spike will produce many flowers, several inches or more in diameter. Plants are excellent for hanging baskets containing only charcoal, but will need fertilizer applications.
For the more advanced gardener, try the butterfly orchid, or phalaenopsis. It is desirable for corsage use. Flower spikes will contain from a few to many flowers. Lavender or white flowers are most common. Flowers will average about two inches across and will remain open for several weeks.
For high elevation gardeners, try the cymbidiums. Cymbidium is an exciting genus with hybrids flowering in a wide range of colors including pink, red, yellow, green, maroon, bronze and white, in bold vibrant tones as well as more delicate pastels and art shades. Their tall, erect, arching or hanging sprays, durability and longevity, ease of cultivation, and usefulness as a potted plant, landscape plant, or commercial cut flower have led to tremendous worldwide popularity. Conventional varieties require cool evening temperatures of about 55 degrees during the late fall and winter months for good flowering to take place. Such conditions occur naturally in Volcano, Kamuela and upper Kona on the island of Hawaii, Kula on Maui, Kalae on Molokai, Pupukea on Oahu, Waimea on Kauai, and other scattered areas, mostly above 1,500 feet elevation, around the state.
The species and hybrids of miniature cymbidiums require basically the same growing conditions as the larger conventional types. A major cultural difference is that most of the miniatures do not require temperatures nearly so cool as their larger relatives. The preferred temperature range for “minis” is 70 to 80 degrees during the day followed by a 10 degree drop at night, a condition much easier to achieve in Hawaii’s lowland areas than that required by the conventional types.
You can minimize orchid care by attaching orchids to a tree like plumeria or calabash, That way you can have dozens of blooming orchids even in a small garden. Other epiphytes like staghorn ferns, bromeliads and some vireya rhododendrons may be incorporated to create air gardens.
Many more rare and interesting species will be available at the plant sale on Oct. 28, along with expert orchid enthusiasts to answer your gardening questions.
Norman Bezona is professor emeritus, University of Hawaii College of Tropical Agriculture and Human Resources.