Elevation makes all the difference for cool-climate plants in Hawai'i
By Heidi Bornhorst
Kwai fah or osmanthus fragrans is a plant we cherish in Hawai'i for its tiny, intensely scented blossoms. In the lowland areas where most of us garden, it is a rather pitiful plant, with scraggly branches, lots of dieback, scorched leaf edges and so on. I remember that a gardener friend from the South told me that they are big trees there.
We were in the Volcano area of the Big Island recently, and as we walked beneath arching hapu'u fronds into our friend's garden, we were greeted by that lovely perfume. I found a kwai fah tree greeting us. The tree was about 30 feet tall, with a trunk about a foot in diameter. It was full of blossoms and every leaf was perfect.
This just helps us see how important elevation, microclimate and soil are. The cool temperatures of higher elevations, the wonderful, rich, young volcanic soil, abundant rain and other factors help this plant, camellias, azaleas, hydrangeas, Japanese maples and other plants from cooler climates thrive in Hawai'i. Many native Hawai'ian rain-forest plants also thrive in this kind of climate, while they struggle and look kind of junk no matter the care you lavish on them or won't even grow at all down in the lowlands.
I loved seeing keiki hapu'u, olelo, 'ohi'a lehua and all kinds of plants sprouting on hapu'u (tree fern, the mother of the Hawai'ian forest) trunks. The climate is so hospitable up there that I even observed two keiki 'ohi'a lehua sprouting in a crotch of an old ti plant. Talk about hapa-haole horticulture!
The delicate white poinsettia, Euphorbia leucocephala, also known as snow on the mountain or the Christ child's flower, is just coming into bloom in higher elevation areas such as Kurtistown and Mountain View. They are already lovely round shrubs full of white flowers up there, whereas I haven't seen any on O'ahu yet. Have you? Please tell us about any good ones that our fellow readers can enjoy.
Protea were abundant and gorgeous in farmers and community markets, which are showcasing many great horticultural products for local growers.
Those crazy out-of-season gold trees are still showing off around town. Some lovely ones can be seen along the freeway near Liliha at Kauluwela elementary school. These lovely large flowering trees are a legacy of state Department of Education and Honolulu Botanical Gardens visionary plantsman Paul Chang, who grew a wonderful legacy of flowering trees at public schools.
News and notes
Mark your calendar for some great upcoming events: The Lyon Arboretum holiday plants sale, featuring lots of ti and Christmas cactus, is up at the arboretum in the back of Manoa Valley. Lots of great holiday garden and gift shopping here; 9 a.m. to 2 p.m. Nov. 23. Information: 988-0456.
The Hawaiian Urban Forestry Field Day includes a walking tour and tree give-away; 9-11 a.m. Nov. 23. Meet at Ho'omaluhia Botanical Garden; call 537-1708.
Heidi Bornhorst is director of Honolulu's botanical gardens. Submit questions to email@example.com or Island Life, The Advertiser, P.O. Box 3110, Honolulu, HI 96802. Letters may be published or distributed in print, electronic or other forms.
Correction: The Hawaiian Urban Forestry field day Nov. 23 is at Ho'omaluhia Botanical Garden; call 537-1708 to R.S.V.P. The location was unclear in an earlier version of this story because of an editor's error. In the same column, the scientific name for Kwai fah, Osmanthus fragrans, was incorrect because of an editor's error.