Saturday | August 19, 2017
About Us | Contact | Subscribe

Plant of the Month for August – Cardboard palm

Updated: 
August 6, 2017 - 12:36pm

The plant known as cardboard palm is neither cardboard nor palm. This low growing species, Zamia furfuracea, is actually a close relative of ancient cycads which have survived since the time of the dinosaurs. The circular crown of the Zamia leaves does resemble palm fronds and the name “cardboard” probably refers to the stiff leathery texture of the leaves, but this member of the Zamiaceae or coontie family is a separate species. Other closely related cycads include the coontie and sago palms, neither of which is a true palm.

The Zamia’s lineage in the cycadophyta as well as its long earthly history makes it an interesting specimen plant. Even a single cardboard palm can add an unusual tropical touch to any garden. It is especially well suited to lower elevations in West Hawaii where the soil is slightly basic and the climate is hot and dry. An excellent xeriscape plant, a cardboard palm will grow well in slightly salty air with very little water.

Cardboard palms are native to the eastern coasts of Mexico and Belize but have been widely cultivated in many tropical and subtropical locations as landscape plants and in colder climates as house plants.

The plant has a short, fleshy trunk that is partly submerged. It collects and holds water for use during droughts. The numerous pinnate (feather-like) leaves radiate out from the trunk in a symmetrical rosette that can get up to 4 feet long. The six to 12 stiff and somewhat fuzzy olive green leaflets that grow along the petiole are often five inches long and an inch wide. They actually do feel like cardboard when touched.

When young, the plant grows very slowly, but growth accelerates with maturity. Healthy specimens in ideal locations can reach over 5 feet tall with a spread up to 6 feet wide when mature.

This plant is considered a gymnosperm, which is an ancient group of plants that produces what is referred to as “naked” seeds. Conifers including pines, cycads and ginkgo are all gymnosperms. Rather than flowers, cardboard palms produce male and female cones as part of their reproductive cycle. A cluster of tan-colored cones rise from the center of female plants ready to receive pollen from the barrel shaped cones produced by male plants. The insects that usually pollinate these plants in their native environment are not present in Hawaii, so hand pollination from male to female plants is needed for production of viable seeds.

Once pollinated, fertilized seeds begin to form within the female plant’s cone. When they are ripe, the cone breaks open to reveal fleshy bright red seeds that are about an inch long. Though they may appear tasty, they are actually poisonous to humans as well as animals. They are, however, the best way to propagate cardboard palms.

Plant mature seeds in a planting mix and keep the medium moist until germination. Seed germination of this species is quite slow, sometimes taking nearly a year. Some of the seeds may not be viable, so plant a few in each pot. The process of hand pollination, along with the lengthy and somewhat iffy germination time, means that many plants on the market today have often been illegally collected from the wild. This practice has reduced the wild population to the point that cardboard palms are now classified as vulnerable. Unless this practice ceases, the plant might soon appear on the endangered species list.

Cardboard palms grow well in sunny locations as well as in partial shade. In full hot sun the leaves can get slightly burned but they will grow more upright. In partial shade the growth will be more horizontal.

This species grows best in slightly basic soil (pH between 7-7.5) that drains well. Though the plant will grow well in moist soil, it is fairly drought, salt and wind tolerant once established. It may only need irrigation for the first year but can live with only our occasional rain water after that.

Very little maintenance is needed for cardboard palms. Lower leaves can be removed as they die but no other pruning is needed. Few if any insects or diseases attack this plant so it will usually remain healthy. Any insects that do appear should be controlled quickly to prevent further damage. Small amounts of fertilizer can be applied occasionally to keep the plant well nourished.

Though somewhat tough and prickly, leaves of the cardboard palm are often used in decorations. The unusual and tropical appearance of the plant makes it a wonderful specimen for a garden or an interesting houseplant. Knowing that you are growing a plant whose ancestors lived when dinosaurs roamed the earth adds to the charm of the cardboard palm.

Call around to local nurseries and gardening departments to see who has them. You might even try some plant suppliers in Waimea or East Hawaii if you can’t find them in Kona.

Diana Duff is a plant adviser, educator and consultant living on an organic farm in Captain Cook.

Gardening Events

Saturday: “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. Volunteers will be able to help with garden maintenance and are invited to bring a brown bag lunch. Water and snacks provided. Call Peter at 323-3318 for more information.

Farmer Direct Markets

Wednesday: “Sunset Farmers Market” 2 to 6 p.m. in the HPM parking lot, 74-5511 Luhia Street in Kailua-Kona (across from Target)

Wednesday &Friday: “Hooulu Farmers Market” 9 a.m. to 2 p.m. at Sheraton Kona Resort &Spa at Keauhou Bay

Friday: “Pure Kona Market” 9 a.m. to 5 p.m. at Amy Greenwell Garden in Captain Cook

Saturday: “Keauhou Farmers Market” 8 a.m. to noon at Keauhou Shopping Center

“Kamuela Farmer’s Market” from 7 a.m. to noon at Pukalani Stables

Sunday: “Pure Kona Green Market” 9 a.m. - 2 p.m. at Amy Greenwell Garden in Captain Cook

Tuesday–Saturday: “U-Pick greens and produce” 10 a.m. to 4 p.m. Tropical Edibles Nursery, Captain Cook.

Plant Advice Lines

Anytime: konamg@ctahr.hawaii.edu Tuesdays &Thursdays: 9 a.m. to noon at UH-CES in Kainaliu - 322-4892

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

Rules for posting comments