A sago palm can add interest and beauty to a tropical garden. Its arching frond-like leaves that emanate from a central crown create a palm-like appearance, hence its name.
Sago palms are not palms, however. Their appearance is only part of their long story.
The sagos that grow here in Hawaii are actually gymnosperms and are more closely related to ancient conifers. Sagos are primitive members of the plant kingdom, native to India, southern China and several Japanese islands. Along with other members of the primeval Cycad genus, sago palms grew in great numbers during the Mesozoic era that ranged from 66 to 252 million years ago. These plants are old souls.
Sago palms are in the ancient Cycadaceae family which contains the single Cycad (Cycas) genus. Of the approximate 50 species in this genus, two are frequently grown here. Both the king sago (Cycas revoluta) and the similar queen sago (Cycas circinalias) often appear as specimen plants, in massed clumps or as potted plants in local Japanese-style gardens. They can add an almost prehistoric focal point to any tropical garden.
The two sagos vary only slightly in appearance and characteristics. Both the king and queen sagos produce long, arching, frond-like leaves and have a wide growth habit 3 or more feet across. They both can remain low to the ground for many years. Both species show tolerance to wind, salt and drought conditions, making them adaptable to lower elevations as well as dry, windy uplands. Their leathery, leaflets have pointed, spiny tips that are sharp to the touch. This feature has protected the species for millennia and continues to do so while making it a good barrier plant.
The king and queen sagos do have slight differences. Both are slow growing but mature queen sagos can develop single or multiple trunks that can reach 20 feet high within a decade. The king sago grows even more slowly but can develop a stout trunk nearly 10-feet tall over time.
As sagos age, they produce attractive light green flushes of new leaves called breaks from their center. This flush, which occurs annually at maturity, adds interest and beauty to these plants. The tender new leaves appear all at once in a feather-like rosette in an upright crown surrounded by soft new leaves. It slowly opens and the leaves become longer and stiffer and create a new layer of arching fronds.
Mature king and queen sagos bear central pollen cones on their male plants. The pollen, when transferred to wooly central ovule-bearing structure on the female plant, produces seeds. These seeds, as well as the offshoots that appear at the plant’s base, can be used to propagate these attractive, slow growing specimens.
Mature sagos will also put out suckers at their base. These can be left in place to create a clump of plants or they can be removed and planted elsewhere. If you decide to remove them, you may want to don some long leather gloves so that you can cut off some lower leaves and avoid getting painfully poked. Once you get to the offshoots, you need to cut them off cleanly from the base. The cut basal end should be allowed to dry before dusting it with rooting hormone and placing it firmly on a rooting medium like a 50:50 mix of perlite and vermiculite. New roots may take up to four months to develop.
Propagation from seeds takes a bit longer requiring removal of the outer fleshy layer and scarification of the inner layer followed by dry storage for six months. After the waiting period, seeds can be planted in shallow flats and covered with porous soil. Again, patience is required for the seedlings to put out a tap root and enough supportive lateral roots to prepare it for successful transplanting.
The resulting plants from either propagation method will have sensitive roots that need to be handled carefully. Once removed from the rooting medium, the plantlets should be placed in the soil at the same level as they were growing in the medium. Sagos can grow well in full sun if given adequate water but may do better in a partially shady location if the sunny location is too hot. When getting established, sagos may need to be watered deeply once a week. Once established they need very little water. Be sure the soil they grow in is porous and drains well as sagos are susceptible to root rot in soil that remains wet.
With such tough armored leaves, sago palms are not often attacked by insects or diseases. Luckily, these spiny specimens require very little pruning or other maintenance. An annual application of a balanced fertilizer can help them thrive and frequent checking for health issues will catch problems early.
About 10 years ago, we lost many sago palms in Kona to cycad scale. Though the widespread infestation has been brought under control, this insect is still here. A scale infestation first appears as tiny white dots on the underside of the leaves. The scale insect (Cycad aulacaspis) usually travels by wind blowing from affected plants. If the scale arrives, persistence is required to effectively treat a sago palm. If the scale appears, you need to prune off infested leaves and move them off site to prevent spreading. The scale can be killed by spraying wherever the insect appears with a combination of neem oil and safer soap. This combination smothers the insect on contact. Repeat the spraying weekly for several weeks being sure to spray both the top and underside of the leaves as well as the trunk and surrounding soil. When the scale is dead it becomes dry and will eventually fall off. Carefully scraping or hosing the dead scale off the plant can hasten removal. Be vigilant and repeat treatment if a re-infestation occurs.
Despite the misnomer of sagos as a palm, the sago part of their name is descriptive. Sago is an edible starch that is obtained from the pith inside the trunk of various palms and cycads and is a staple food in parts of the tropics. The pith from the stems, roots and seeds of sago palms is traditionally scraped out, washed, and dried to a course flour which is washed repeatedly to leach out the natural toxins. Sago flour as well as all parts of the sago palm are toxic to humans and their pets if eaten untreated.
In his book, “The Island of the Colorblind,” which includes the shorter Cycad Island, neurologist and author Oliver Sacks discusses the widespread traditional use of cycad sago flour and its possible effects on the native population of Guam.
A disease called lytico-bodig locally which includes symptoms including progressive paralysis and/or symptoms resembling Parkinson’s disease and dementia has often been linked with the use of sago flour in their diet. Though indications of the link between this plant and the disease are, it remains unproven. Despite the continued consumption of sago in traditional cultures, reading Sack’s book made it clear to me that I would not be eating any part of my sago palm.
Many gardens in Kona have at least one sago palm. If you want to acquire one or some, you can always ask a neighbor for seeds or an offshoot. Otherwise look for them at local nurseries or call Margo from Sunrise (at 640-9191) to see if she can find one for you.
You might want to consider including at least one of these ancient specimens in your landscape. They are attractive, slow growing rugged plants that can, with minimal care, grace your garden for a lifetime and then some.
Diana Duff is a plant adviser, educator and consultant living in a dryland forest north of Kailua-Kona.
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: “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 and Thursdays: 9 a.m. to noon at UH-CES in Kainaliu – 322-4892
Mon., Tues. and Fri: 9 a.m. to noon at UH CES at Komohana in Hilo 981-5199 or himga@hawaii.edu