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Norman Bezona Prof emeritus University of Hawaii College of Tropical Agriculture

Norman Bezona
Prof emeritus
University of Hawaii
College of Tropical Agriculture

Are you looking for ritzy gifts with Lei Day and Mother’s Day just around the corner, then consider orchids.  To most people the word “Orchid” immediately brings to mind the purple flowered Cattleyas.  This orchid has been and still is the most popular.  The genus Cattleya contains only 50 species in the orchid family containing over 15,000 known species. More are being discovered each year. Most grow as epiphytes in trees, but some grow in soil and even on rocks.

Many orchids are coming in to bloom now that the rains have returned especially in mauka Kona. Wild Chinese Ground Orchids are in full glory under towering Hapuu and Ohia forests.

For an opportunity to visit the unique Kona Cloud Forests, contact Janet Britt of the Hawaiian Islands Land Trust at 769-4343. The Land Trust has organized the tours to encourage folks to protect our fantastic forests. Kona Cloud Forest Sanctuary is hosting the up coming tour, Wednesday May 4th. Space is limited so call to RSVP your spot ASAP.   

Cattleya_labiata_rubra_schuller

A Purple Cattleya –

There are a number of orchid species and hybrids that are easy to grow in Hawaii.  Orchids are well adapted here and many species need almost no care.  In fact, several orchids have naturalized and can be found growing like in abundance.  These include the Bamboo Orchids, or Arundina, from the East Indies.  This orchid is common in open, grassy areas of the Big Island.  The Phaius or Chinese Ground Orchid is found in moist forested areas along with the Spathoglotis or Malayan Ground Orchid.

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.

The Epidendrums are a staple for the Hawaiian Lei

The Epidendrums are a staple for the Hawaiian Lei

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.

Vandas at Kew Botanical Gardens. Some of the most exotic colors in the plant world.

Vandas at Kew Botanical Gardens. Some of the most exotic colors in the plant world.

The Terete Vanda “Miss Joaquim” was for years the major orhcid produced in Hawaii for leis.  Now dendrobiums are becoming more popular. 

There are more than 700 species of dendrobium including the “Honohono” which resembles the Wandering Jew in the shape and arrangement of its leaves.  The more common ones grow with ease.

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.

The cool weather Cymbidiums will grow well outside the tropics

The cool weather Cymbidiums will grow well outside the tropics

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 F 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 1500 feet elevation, around the state. 

Oncidiums - easy and fun. Plant in trees and anywhere epiphytic and watch the show.

Oncidiums – easy and fun. Plant in trees and anywhere epiphytic and watch the show.

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 F 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.

To grow most orchid species, here are some hints:

Most orchids require partial shade for best growth.  A good rule to follow is to give the plants all the light they can stand without scorching.  Excessive shade will result in lush, dark green foliage and few flowers.  Too much light may produce scorched spots on the foliage.  This means shade is needed immediately.  Saran, lath or trees may be used for overhead shade.

Many Cattleya, Epidendrum, Oncidium and Vanda species will tolerate temperatures down to 45 degrees if in a sheltered location.  But most orchids prefer minimum night temperatures of 55 – 60 degrees F.  In Hawaii, there really is no maximum temperature for orchids if the humidity and ventilation are increased in proportion to the rise in temperature.  In general, temperatures that are comfortable for people also are agreeable for orchid plants.

Nun's Orchid

The Nun’s Orchid – growing wild throughout the cooler areas of Kona’s Cloud forest.

Watering orchids must be adjusted to the need of each plant and the media in which it is grown.  Many orchids can be grown in coarse cinder or even gravel.  A large plant will require more water than a small one; orchids in large pots will dry out slowly compared to plants in small pots.  Orchids in active growth will require more water than those in a semi-dormant state.  This means that plants will require more frequent watering during the warm summer months than during the cool winter season.  Over-watering has been the main cause of death of orchid plants.  Roots will rot, and the medium becomes soggy and soft, which is harmful to the plant.  Remember, never water a wet plant under any circumstances.

Fertilization can be a controversial subject.  Plants growing in cinder or rock may be fertilized with a complete liquid fertilizer of a 1-1-1 ratio.  Follow the directions on the label.  You may apply this mixture every 3 to 4 weeks during the year in place of a normal water application.

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. 

Insects like the orchid fly, orchid weevil and scale insects are seldom a problem but may be controlled with insecticides as necessary.  Mites may also give you a little trouble occasionally.  Again, be sure to read and follow label directions.  There are also many garden books on orchid care as well as opportunities to get involved in our local orchid clubs.

U.H. College of Tropical Agriculture and Human Resources