Plant of the Month for October 2024: Gingers

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Known to us a shampoo ginger, awapuhi is an attractive ginger to include in a tropical garden. (Forest and Kim Starr/courtesy photo)
The ‘Kimi’ cultivar is a popular variety in home and commercial gardens. (Debra Agapito/Courtesy photo)
Red ginger flowers are a wonderful addition to a cut flower arrangement. (Forest and Kim Starr/courtesy photo)
The ‘Jungle Queen’ flower is a lovely light pink. (Debra Agapito/Courtesy photo)
Torch ginger is a dramatic “show stopper” of a flower. (Forest and Kim Starr/courtesy photo)
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The Ginger family (Zingiberaceae) has nearly 1,000 members. The roots of two well-known spices, turmeric or ‘olena (Curcuma longa) and ginger (Zingiber officinale) have been highly prized in international trade for more than a thousand years. Most of the species in the family are tropical plants that grow well here. Several exotic specimens can add interest and beauty to a Kona garden. These plants usually grow from fleshy rhizomes, have aromatic tall, cane-like stems with large leaves and stunning flowers.

Several species in the Hedychium genus are off my recommended list despite their beauty and fragrance. The white, yellow and kahili gingers have proven very invasive particularly in Volcano area and the National Park. Only grow these if you are willing to pick all the flowers when they bloom, never let them go to seed and never dig up the roots and throw them “away.”

That said, let’s talk about some lovely species that make excellent garden specimens, some of which are well suited to spectacular cut flower arrangements.

One of my personal favorites is shell ginger. A member of the Alpinia genus it is known botanically as Alpina zerumbet. The plant can produce multiple stems that can grow eight feet or more and will spread wide to make a lush hedge. It is easy to control the size by merely cutting off any long stems.

Though likely native to Papua New Guinea, the first record of shell ginger plants being cultivated here dates back to 1874. It has become a popular landscape plant since then, partly due to the interesting pendant cluster of flowers that each resemble small sea shells. Though not fragrant. the flowers make up for that by their beauty. Following flowering, the shells become small round seed pods which mature to an orange color before splitting and releasing the multiple seeds within. You can propagate shell gingers from the seeds.

The leafy stems provide a lush tropical appearance. The dark green leaves set off the mostly white flowers nicely. They also offer serve many cultural and medicinal uses throughout the tropics. You may be able to find an interesting shell ginger cultivar has variegated leaves. This is an ideal plant for a medium sized garden with full sun or partial shade.

Sharing the same genus are several species known botanically as Alpinia purpurata. Though these too can become invasive in upland forests, when grown in a controlled environment, they do not pose a threat. They are often used as an attractive addition to a landscape. Both a red and a pink variety are included in A.purpurata.

Native to the Solomon Islands, Vanuatu and New Caledonia these plants were introduced to Hawaii before 1930. They are not often grown in home gardens as well as in commercial operations. They are highly prized as cut flowers. Watch for the plantlets that may appear at the base of the inflorescence. They will drop off and can be propagated as new plants.

Both the red and the pink varieties are long lasting cut flowers that can add drama to a flower arrangement. Look for the ‘Jungle Queen’ and ‘Kimi’ cultivars. Both are robust growers with beautiful flowers. ‘Kimi’ is a deep pink or magenta blossom while Jungle Queen is a lighter, more delicate pink color. These cultivars can only be propagated by root division.

The long leafy shoots of A.purpurata can grow to twelve feet or more. The shoots can be easily cut to maintain a desired height, however. Both colors are well suited to a tropical garden bed in either full sun or partial shade.

Torch gingers known botanically as Etlingera elatior have long leafy stems that support a large red ‘torch’. This is a dramatic specimen in a garden and a stunning addition to a cut flower arrangement.

Likely from Malaysia and Indonesia, the flowers and seeds of this plant are eaten there. Here in Hawaii, we simply enjoy them for their exotic appearance. The Hawaiian name for them is ‘awapuhi ko’oko’o referring to their resemblance to a walking stick when the flower is forming.

Like the other ginger species mentioned here, they can grow in full sun or part shade. All of these gingers do best in rich soil that drains well but gets a regular supply of water. None are drought tolerant.

Two other gingers worthy of mention are both in the Zingiber genus. Zingiber zerumbet is known to us as shampoo ginger or ‘awapuhi. Zingiber spectabile or beehive ginger produces a large waxy yellow flower that is a dramatic addition to an arrangement.

Z.zerumbet plants were likely brought to Hawaii by the early Polynesian settlers. The leafy stems may grow to two feet or more and support a tight inflorescence that resembles a cone. These cones are green when young and turn red as they age. When mature, they exude a fragrant sudsy fluid that early Hawaiians used as a shampoo. They are attractive edging plants and can do well in partially to fully shady locations.

Z.spectabile is native to Malaysian forests where it provides an interesting element to the understory. The stems can grow quite tall, over 6 feet in sunny locations, but in partial shade will maintain a lower profile. The flower heads are large layered cones that are an attractive species in the garden and as a cut flower.

All gingers require warm temperatures and some protection from wind, strong sun and salt spray. They prefer rich, moist soil and some shade or afternoon cloud cover. They are a perfect addition to gardens above 1,000 feet in elevation but can do well at lower elevations with some shade and adequate irrigation. Gingers need space. The leafy shoots of some varieties can grow more than 10 feet tall.

Few pests attack ginger, perhaps because of the strong gingery aroma in the stems. If any Insect attacks are caught early and treated, you can prevent them from spreading. Preventing insect attacks on succulent new leaves and avoiding problems like root rot relies on good cultural practices. Though gingers prefer moist soil, good drainage is essential to prevent root rot. Monitoring your plants regularly is essential to maintaining their good health.

Selective fertilization will encourage blooming rather than leaf production. A fertilizer low in nitrogen but with more phosphorus and potassium and some micronutrients can accomplish this. Gingers, do very well in soil that is kept mulched. This will retain moisture and help keep the soil alive.

These plants grow well here and offer lots of beauty in the garden and in arrangement. Consider finding a place in your garden for one or more of these gingers.

Gardening events

Saturdays: Work Day at Amy Greenwell Garden from 9 a.m. to 12:30 p.m. Meet at the Garden Visitor Center across from the Manago Hotel in Captain Cook. Come with a mask and be prepared to practice social distancing. Volunteers can help with garden maintenance and are invited to bring a brown bag lunch. Water and snacks provided.

Saturday-Sunday, Oct. 5-6: The 34th annual Hawaii Tropical Fruit Growers International Conference continues at the Maui Food Innovation Center with off-site farm visits. Talks and workshops ongoing. For more information go to htfg.org.

Saturday-Sunday, Oct. 5-6: 13th Annual Hawaii Farmers Union United Convention at the University of Hawaii Maui College. Joining with the Hawaii Tropical Fruit Growers and the Maui Food Innovation Center, the convention will focus on sustainable and regenerative agriculture for Hawaii. Presentations, workshops and community networking on a wide range of topics. Free to the public. Go to www.hfuuhi.org for more information.

Save the dates

Saturday, Nov. 2: Arbor Day Celebration, from 9 a.m. to 2 p.m. at Amy Greenwell Ethnobotanical Garden in Captain Cook. Featuring a free tree giveaway of useful and beautiful native trees and shrubs. In addition, the garden will hold a plant sale and host displays on horticulture and conservation. Activities for children, and even a public display by some talented conservation dogs will be available as well.

Thursday, Nov. 7: Coffee Tasting Workshopmorning session, 9 to 11 a.m.; afternoon session 1:30 to 3:30 p.m. at the Kona Research and Extension Center Conference Room in Kainaliu. Learn how to brew the perfect cup of Kona coffee. Registration is required at www.hawaiicoffeeed.com/kccfcoffee. Donation of $25 includes a 2024 Kona Coffee Cultural Festival button.

Friday, Oct. 11: 10th Annual Landscape Maintenance Conference from 8 a.m. to 4 p.m. at the Westin Hapua beach Hotel on the Kahala Coast of Hawaii. The conference theme is Fire and Water.

Farmer direct markets

(Check websites for the latest hours and online markets)

Wednesday and Friday: Ho’oulu Farmers Market, 9 a.m. to 2 p.m. at Sheraton Kona Resort at Keauhou Bay

Saturday: Keauhou Farmers Market, 8 a.m. to noon at Keauhou Shopping Center; Kamuela Farmer’s Market, 7:30 a.m. to noon at Pukalani Stables; Waimea Town Market, 7:30 a.m. to noon at the Parker School in central Waimea; Waimea Homestead Farmers Market, from 7:30 a.m. to noon at the Waimea middle and elementary school playground.

Sunday: Pure Kona Green Market, 9 a.m. – 2 p.m. at Amy Greenwell Garden in Captain Cook; Hamakua Harvest, 9 a.m. to 2 p.m. at Hwy 19 and Mamane Street in Honokaa.

Plant advice lines

Anytime: konamg@hawaii.edu

Tuesdays and Thursdays: 9 a.m. to noon at UH-CES in Kainaliu: 322-4893 or walk in.

Mon., Tues. and Fri: 9 a.m. to noon at UH CES at Konohana in Hilo, 981-5199 or himga@hawaii.edu

Diana Duff is a plant adviser, educator and consultant living part time in Kailua-Kona.