Māmane (Sophora chrysophylla) “Well, you do know …?”

    Several years ago, I was on a hike in Nānākuli Valley with Joel Lau and several other botanists. We were exploring some of the gulches in the back of the Valley and I was delighted with what I had seen: some beautiful holei, a giant ‘iliahi, the endangered kulu‘i and Abutilon sandwicense. But what excited me most were the dozen or so māmane perched above us now on a cliff face. Māmane are rare on O‘ahu and these were the first I had ever seen. Unfortunately, as I looked up, I could not see a single seedpod on any of the trees. The group had decided to stop here for lunch, but, rather than eat, I decided to look around at the base of the cliff for māmane seeds. I had collected māmane seeds several times before on the Big Island, usually just picking the distinctive pods directly from the tree, but occasionally gathering the bright orange or yellow seeds from the black ‘a‘a lava beneath the plants. I figured that against the dark rich soil at the base of the cliff, I shouldn’t have too much trouble finding the brightly-colored seeds. After fifteen minutes of fruitlessly scratching at the dirt like a chicken looking for bugs, I was getting pretty discouraged. Joel was sitting nearby eating his lunch so I shared my frustration with him, muttering something about how weird it was that I couldn’t find a single seed with so many trees hanging just above me. Joel very calmly looked at me and said, “Well, you do know that the māmane on O‘ahu have brown or black seeds?” “Ahh oh! No. Thanks, Joel,” I sheepishly replied. Fifteen minutes later, we began the long hike out of the Valley. I was now happy as a clam — with my dozen or so māmane seeds safely stowed away in my backpack. 

Habitat & Appearance: Māmane grows on all the main Hawaiian Island except Ni‘ihau and Kaho‘olawe in many different habitats. It can be seen in dry shrublands, dry and mesic forests, and is common in the subalpine areas of Maui and Hawai‘i where its seeds are a primary food for the endangered palila (one of Hawai‘i’s endemic honeycreepers). Reportedly, it is also rarely found in wet forests although I’ve never personally seen a wet forest māmane. All māmane have the same characteristic compound leaves, bright yellow pea-like flowers and oddly constricted and winged seedpods. However, they vary considerably in growth form. For example, in the dry open shrublands of Kona on the Big Island, māmane tend to be short (less than ten feet) and bushy, while in the uplands between Mauna Kea and Mauna Loa they are beautiful small trees (often more than ten feet tall). Here on O‘ahu, nearly all the wild māmane I’ve encountered were small lanky trees with few side branches. 

Māmane in Hawaiian Culture: Tough and durable, Hawaiians used māmane wood for hale, a variety of tools and weapons, and hō‘ula sled runners. It is also excellent firewood and was used by high priests as a symbol of authority or to ward off evil. Later, māmane wood was used for fences and wagon wheels and frames (Lydgate 1883). Māmane flowers and seeds are still strung into lei. (Medieros et al. 1998 has an excellent summary of māmane ethnobotany.)

Collecting Seeds: Observers have reported different flowering periods for māmane at different locations. On O‘ahu, the māmane I’ve seen wild or cultivated normally flower in winter or spring, producing mature (dark brown to black) seedpods in late spring and summer. Often the mature pods remain attached to the plant for many months making seed collection an easy task when using nailclippers to get through the tough pods. Even after the pods have fallen or dispersed, you can usually find good seeds on the ground directly below the plant. Be sure to thoroughly wash and sterilize (10% bleach for 15 minutes) all newly-collected seeds as a precaution against harmful adhering microbes. Māmane seed will remain viable for at least ten years when stored in the refrigerator.

Growing from Seed: After soaking overnight in a shallow pan of water, scar māmane seeds with either sandpaper or a nailclipper and sow them. (Seeds from Maui or Hawai‘i stain the water orange; kapa-makers may want to experiment with this potential dye.) Using Method One or Two, the seed will begin to sprout in about two weeks. Similar to the common garden pea or our native uhiuhi, the cotyledons (seed leaves) of māmane remain below the media while a thin and slightly compound true leaf is the first greenery visible in the germination tray or pot. Seedlings grow at a moderate pace that is dramatically quickened by additions of control-released or foliar fertilizer. With the added fertilizer, the seedlings will be 8-10 inches tall in approximately six months. Normally, I plant them out at this size; however, because subsequent growth in the garden can be slow, you may wish to repot your māmane and keep them in the nursery until they are taller. Māmane seedlings are susceptible to attacks from mites and whitefly. Repeat sprayings of horticultural oil will keep these pests under control.

Growing from Cuttings: I have never tried to propagate māmane from cuttings. 

Growth in the Garden: (Note: My experiences here are restricted to the O‘ahu māmane variety.) Plant your māmane in a location that receives lots of full sun. Once in the ground, māmane tend to grow slowly. A good rain or supplemental watering (in moderation) seems to encourage faster growth. While I have not tried fertilizing, my experience with seedlings suggests it would also help. After three years, a three-foot-tall māmane in one of my restoration sites flowered and fruited. Meanwhile, at another site, I have a six-foot-tall māmane that has yet to flower after five years. Interestingly, most of my cultivated māmane have many more basal or side branches than the wild parent plants, perhaps, because the parents grew in a shadier environment. 

Diseases & Pests: Few pests have bothered my māmane. Occasionally, Chinese rose beetles will chew off the small leaflets or a stem will be killed by a black twig borer or an infestation of hibiscus snow scale. (See Enemies in the Garden for ways to combat these pests.) With that said, I have lost numerous plants over the years. Most have died early, I believe because I failed to water them adequately. These were plants I planted out in restoration plots, not gardens, where the goal was to have them live unassisted. Others, I suspect, were attacked below ground by root mealybugs or, perhaps, a harmful fungus. Therefore, I recommend a regular watering schedule for young plants and frequent visual inspections at the base of your māmane just below the soil surface. 

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