Native Hawaiian Garden (7722)

Achyranthes splendens var. rotundata (‘Ewa hinahina) – The power of volunteers

It was 1997, and I was an Instructor of Biology at Leeward Community College when we received a call for help from Dan Moriarty of the US Navy Staff & Civil Office at the Naval Air Station at Barbers Point. There was a small cluster of about 30 endangered plants, Achyranthes splendens var. rotundata, growing in one corner of the Station that was being crowded out by a very aggressive alien shrub called Pluchea. Dan wanted to know if we could gather some students and faculty together and remove the Pluchea surrounding the Achyranthes. We said yes, and on an early Saturday morning in February, about 60 faculty and student volunteers boarded a white Navy school bus destined for the Achyranthes site. In about four hours, with Dan frantically running back and forth telling us which plants to pull out and which plants to leave in the ground, we achieved our goal. There was now a ring of open space encircling the Achyranthes cluster while nearby uprooted piles of Pluchea were left to rot in the hot sun. We were all very proud of ourselves!

Following the workday, Dan and I began talking about making this stewardship a regular fieldtrip experience for our students. Unfortunately, Dan passed away shortly after these talks began, and we had to start anew with another Navy representative, Ensign Carrie Booth. From 1997 to 1999, about six times a year, students from Frank Stanton’s Environmental Science class and my own worked at removing more and more Pluchea from the Achyranthes site. As this work continued, an amazing thing happened; the open spaces we were creating were being filled not by Pluchea and other weed seedlings but by native plant seedlings of naio, maiapilo, ‘ilima, pā‘ū-o-Hi‘iaka and even Achyranthes! Fortunate would have it that the Pluchea we were removing was a sterile hybrid, Pluchea x fosbergii, that was incapable of producing viable seed. When it was removed, native plant seeds still in the soil began to sprout and grow.

In 1999, the Naval Air Station closed and the US Fish & Wildlife Service took ownership of the 37-acre site (naming it the USFWS Pearl Harbor National Wildlife Refuge, Kalaeloa Unit); the Unit came under the direction of the amazing Nancy Hoffman, O‘ahu Refuges Manager. From 2000 to 2014, with incredible logistical, supply, and equipment support from Nancy, Frank, Nancy, and I, along with over 10,000 student and faculty volunteers (sometimes from places as far away as Alaska and Japan) continued our recovery and restoration visits to the Unit. Later, from 2014 to 2018, we helped to establish a new semi-cultivated population of Achyranthes nearby at The Kalaeloa Heritage Park. When last I checked (pre-COVID-19 for the Unit and 2022 for the Park), both populations were still doing well with, maybe, a hundred Achyranthes at each site.

Habitat & Appearance: Achyranthes is a 3-6 foot tall shrub with silvery (because of microscopic hairs that reflect the intense sunlight) leaves. During the spring and summer, the plant is easily recognizable by the long and numerous flower/fruit spikes that emerge from the branch tips. At one time Achyranthes was likely a common plant on the ‘Ewa Plains. (Under the right conditions, with all those seeds, the plant behaves like a weed!) Today, however, wild Achyranthes splendens var. rotundata can only be seen in four places on O‘ahu: the US Fish & Wildlife Service Kalaeloa Refuge Unit, a few small fenced enclosures in Campbell Industrial Park, a small population at Ka‘ena Point, and on some steep-walled gullies in Mākaha Valley. Wagner et al (1990) also state it grows on Moloka‘i and Lāna‘i but I am unaware of the status of these plants. A more common variety, A. splendens var. splendens is found on Lāna‘i and Maui.

Two-week-old seedlings. Adult Achyranthes at Kalaeloa. Mealybugs on young plant. Deadly brown scale on mature plant. Ripe Achyranthes utricles.

Achyranthes in Hawaiian Culture: Today, no one seems to know the Hawaiian name for Achyranthes. This is indeed sad because with the loss of a plant’s Hawaiian name, its uses and mo‘olelo (stories) also disappear. Today, people have begun calling Achyranthes the ‘Ewa hinahina. This is appropriate since it once occupied much of the ‘Ewa Plains and the tiny white hairs on its leaves give it a silvery or grey color.

Collecting Seeds: The spikes of utricles (a thin-walled fruit containing one seed) ripen in late summer and early fall. Avoid the temptation to collect more utricles than you need. And, to maintain genetic diversity in your garden, it’s better to collect five utricles from ten plants than 50 utricles from one plant. The utricles store well in a refrigerator for future use.

Growing from Seed: Planted in any clean, well-drained media, Achyranthes seeds easily sprout in about two weeks after an overnight soaking in tapwater. (Soak and sow the whole utricle; it’s not necessary to remove the seed within.) Not all seeds are viable, so, it’s a good idea to sow 2-3 utricles per container, or you can sow everything in a single tray and transplant the seedlings. Seedlings grow pretty rapidly and will grow even more quickly if lightly fertilized. However, it’s important to keep the seedlings in full (or nearly full) sunlight. Otherwise, they will grow spindly with poorly adapted leaves (i.e., green instead of silvery leaves). The plants should reach six inches in height in about six months. The seedlings are susceptible to mealybugs and scale insects; bad infestations will kill them.

Growing from Cuttings: It is almost too easy to grow this plant from cuttings. Plant 4-6 inch cuttings in any clean, well-drained media. Treating the cutting with rooting hormone is probably a waste of money, but you can do it if you like. Place individual cuttings in a small humid container such as a clear plastic cup with a lid; a group of cuttings can go into a larger clear storage container. Keep the container in bright light but not direct sun (to avoid overheating) and the cuttings will begin rooting in about a week. (Cuttings will also root under a misting system but be careful the leaves don’t begin to rot.) Wait another 1-2 weeks before removing the rooted cuttings from the clear container. Out of the container, they should be transitioned to full sunlight. Wait another month before transplanting them to a larger container or into the garden.

Growth in the Garden: Achyranthes will grow in about any soil type but do best in well-drained calcareous or cinder-rich soils. They can reach 1-2 feet in height in less than a year and 3-6 feet tall in two. They will begin flowering and fruiting within one year. They are not long-lived plants, lasting two to, maybe, ten years. They actually seem to live longer if you torture them with no watering and no fertilizer. In fact, the longest-living plants I’ve seen are wild plants in Kalaeloa whose trunks are restricted to a tiny hole through a large slab of exposed reef rock.

Diseases and Pests: Achyranthes adults remain targets for mealybugs and scale insects. The mealybugs can cluster at the stem and flower tips. Or, they can infest the roots. Scale insects are usually seen on the stems and leaves. Please refer to the Enemies in the Garden webpage for ways to combat these pests. A particularly nasty scale is a brown, hard-shelled type (see photograph) that reproduces rapidly and can kill your plant in 1-2 weeks. Pruning off the infested branches and treating the remaining plant with horticultural oil and a systemic pesticide works best on this villain. Achyranthes are also susceptible to root-knot nematodes and pathogenic fungi in the soil. Treating these successfully is very difficult. Usually, the best 'cure' is to find another distant location in your garden and try again. Finally, don’t confuse the short lifespan of Achyranthes for a disease or pest problem in your garden. If you want to display this plant for a long time, you’ll need to occasionally replant new plants to replace the senescent ones.

Ā ā Ē ē Ī ī Ō ō Ū ū