Maiapilo (Capparis sandwichiana) – “This can’t be a native plant!”

It was the early 1990’s, and I was touring Maui with a former girlfriend, Katharine. We'd started out early that morning and were headed south past Mākena in our rental car. The dry rocky landscape was dotted with wiliwili trees and large ‘ilima. As we drove through a small grove of wiliwili near the road, Katharine spotted a bright green shrub with many large white flowers under two wiliwili trees. “What type of plant is that?” she asked me. Not recognizing it, I pulled over and we got out to take a closer look. The plant was flawless, not a single dead branch or deformed leaf. Katharine cupped one of the large pinkish-white flowers in her hand and beckoned me, “Bruce, come and smell this flower – it’s wonderful!” She was right; this beautiful flower had a delightfully sweet fragrance. “So, what is it?” she asked me again. With most of my knowledge of Hawai‘i’s native flora coming from books, not experience, and wishing to impress Katharine, I said, “This can’t be a native Hawaiian plant! It’s just too showy. Look at all those big flowers. And, the leaves are perfect – no insect damage at all! It must be an introduced shrub – maybe, something that escaped from one of the golf courses we past by earlier.” Satisfied with my answer, she and I got back into the car and continued our adventure. It wasn’t until later, back at our hotel room with my assorted plant books that I discovered my error. The shrub with the big white fragrant flowers and perfect leaves was – you guessed it – a maiapilo. So much for impressing my girlfriend.

Habitat & Appearance: Maiapilo is most often seen in coastal environments. However, it also grows in open dry forests and shrubland. It’s found on all the main Hawaiian Islands, as well as some of the Northwest Hawaiian Islands. Some varieties of maiapilo are extremely prostrate, spreading over sand and rocks, while other forms grow into a small tree; the tallest maiapilo I have ever seen was a ten-foot-tall tree with a trunk four inches in diameter growing in leeward East Maui. Maiapilo leaves are papery and oval. The flowers are large, sometimes six inches across (but wild plants at different locations often vary in flower size), white, and have a very pleasant fragrance – unlike the fruit. The flowers last just one night, opening in the evening and collapsing with a pinkish tinge by midmorning (except on rainy days when they will stay open a few hours longer). One would guess maiapilo flowers attract moths to aid pollination. The size and shape of maiapilo fruit can also vary from site to site; some have fruits that look very much like a small pickle while others have smaller more rounded fruits. Regardless of the size and shape, the fruits all turn from green to yellow when ripe. Inside is a stinky yellow-orange pulp containing many round black seeds.

(Top to Bottom) Ripe maiapilo fruit peeled open to reveal seeds (photograph courtesy of Forest & Kim Starr ©). New seedlings. Mature plant at Leeward Community College. Header photograph courtesy of Sebastian Marquez ©.

Maiapilo in Hawaiian Culture: I’m often asked why I became interested in native Hawaiian plants. I must admit my initial interest was their endemism and a desire to help save these unique plants from extinction. However, in addition to this, what sustains my interest today is the many meanings and mo‘olelo (stories) associated with native plant names. Maiapilo is one such example. When Hawaiians first saw this endemic plant they noticed the small oblong fruit. The fruit is green when immature and growing, turning yellow when mature and ripe. It must have reminded them of a fruit they knew well, the mai‘a (banana). However, unlike the mai‘a fruit with its sweet fragrance and taste, when they peeled away the skin of the maiapilo fruit, the flesh had a foul odor (pilo). Putting the two words together gives you an excellent description of the plant: the plant with fruits that look and turn yellow like a banana but smell bad when you peel them – the stinky banana plant.

Marie Neal (In Gardens of Hawai‘i) states that Hawaiians used maiapilo to heal broken bones by applying the pounded plant to body joints (but not directly on the injured site). Flower buds of a maiapilo relative, Capparis spinosa, are harvested and eaten worldwide; we refer to the buds as capers.

Collecting Seeds: I most often find ripe fruits during the fall but have collected as early as May and as late as January. Look for the yellow-orange mature fruit. Unfortunately, even though humans find maiapilo fruit disagreeable, birds do not and often you will only find the hollowed-out skin of the fruit. (Securing a small net bag around the immature fruit such as the one pictured to collect hao fruits is one way to discourage hungry birds.) Still, look carefully because the birds sometimes leave a few seeds behind. Another source is the older, dried and brown fruits (sometimes on the ground beneath the plant). These too may have seeds missed by the birds. However, if you collect these older fruits be sure to thoroughly clean and sterilize the seeds. Finally, green but full-size fruits will ripen and yield viable seed if you treat the fruit as a cut flower, placing the fruit’s stem in water and recutting and replacing the water each day. However, this will only work if the fruit truly is full-size and not still maturing. Often, a ripe fruit will contain both viable black seeds (that look a bit like a tiny snail shell) and nonviable white/yellow seeds; viable seeds will sink if cleaned and placed in a pan of water.

Growing from Seed: Fresh maiapilo seeds seem to germinate more quickly than cleaned seeds stored (five years and counting) in the refrigerator. If you use refrigerator-stored seeds, let them initially rehydrate for a day outside the refrigerator, then, soak the seeds an additional 2-3 days in a shallow pan of water. Using either Method One or Two, maiapilo takes 1-4 weeks to sprout. If this is your first time with maiapilo, I encourage you to use Method One; you’ll likely get a greater percentage of seeds sprouting and you can better protect the seeds and young seedlings from predators such as slugs, insects, birds and mice. Very young seedlings are also susceptible to damping-off fungi, particularly, if watered too frequently. Either foliar or controlled-release fertilizer works well to speed the growth of young seedlings through this vulnerable period. Occasionally, spider mites will attack seedlings in the nursery; repeated sprayings of horticultural oil will normally control this pest. When the main truck/stem of your maiapilo is about ¼ inch in diameter, you can consider planting it into the garden or repotting.

Growing from Cuttings: I have never grown maiapilo from cuttings but others have. According to them it’s not that difficult provided you have a mist chamber (see Plants from Cuttings).

Growth in the Garden: While the majority of native Hawaiian plants look their best during the cool wet cloudy winter, maiapilo is a clear exception being exceptionally vigorous and beautiful in the middle of the hot dry sunny summer. Therefore, pick a location in your garden accordingly. If your plant is small, consider protecting it from larger pests (e.g., snails, mice) with a wire cage until it has grown large enough to endure such occasional abuse. Good soil drainage is important; planting your maiapilo on a mound of cinder and soil is an easy way to meet this requirement if you’re in doubt. Sometimes, even when done with care, a newly-transplanted maiapilo will drop all its leaves. Don’t panic. Continue to lightly water the plant once a week and it will likely flush out with a new leaf set within a month. Once establish, cut way back on watering. Overwatering is a sure way to kill a maiapilo. With lots of sun, your plant should grow quickly and begin flowering and fruiting within a year or two. While maiapilo has a long flowering period, the plants I’ve grown do occasionally take a break, so, don’t expect to see those big fragrant flowers every evening. Treated properly (i.e., full sun, good drainage, little water), maiapilo have a moderate lifespan of ten-plus years.

Diseases & Pests: The most serious killer of maiapilo in the garden is overwatering. Cabbage butterfly caterpillars and leafcutter bees sometimes target maiapilo leaves making them unsightly. Powdery mildew will afflict maiapilo mistakenly planted in a wet shady site. After more than a decade of observation, I still cannot explain why, occasionally, one or two of the plant’s stems will quickly yellow and wither, although this phenomenon is more common during Hawai‘i’s wetter winter season. Until someone does figure this out, the safest thing to do is quickly prune and discard the dead stem.

Ā ā Ē ē Ī ī Ō ō Ū ū