Hawai'i Gardens
Rogue eggplant classified as noxious weed

By Heidi Bornhorst
Special to The Advertiser

Here are some recent letters:

Can you identify this plant (tree) that cropped up in my tiny flower bed? It is now about 6 feet tall, full of thorns and has green berries that turned to gold. None of my gardening friends can ID it. Is it worth keeping?

— Laura McLeod, Mililani

Dear Laura,

It is a weedy type of eggplant. Some people like to eat it, according to Nathan Wong of Honolulu Botanical Gardens and the community garden coordinator.

However, it has been classified as a noxious weed by the U.S. Department of Agriculture, so you should get rid of it, bag it and trash it. Don't try to compost something like this, as the many tiny seeds could grow and the thorns are hard to deal with as you are sifting your compost.

It is called Solanum torvum by plant scientists. Ma khuea phuang is the Thai name. It is used as a vegetable by Thais and others from the region. It is also called Turkey eggplant, pea aubergine, nightshade. In the Philippines it is called talong na ligaw and tandang-aso; in Okinawa, seiban nasubi; and in Vietnam, ca phao.

We often get new weeds or even interesting plants in our gardens.

Many are "gifts" from the birds. If a plant has fruit that are 'ono to birds, or has red fruit that attract hungry birds, the plant can become a weed. This one must be 'ono to them. I have seen it a lot in Mililani Mauka in the old pineapple lands. People may have planted the original ones up there as it is a favored plant, reminding some of the home, gardens and food they left behind.

Some examples of bird-spread plants are strawberry guava and octopus tree (red fruit, lots of tiny seeds and a weedy, easy and fast-growing nature). The Mickey Mouse plant, maile pilau and Fukien tea are other plants that often pop up in Island gardens. Maile pilau has small orange fruit with one sticky seed inside. Birds eat the fruit, and the seed will stick to them until they can drop it off — maybe in your garden.

The birds can't help but eat and spread some of these weeds, but we can. Our precious native Hawaiian forests and unique plants deserve our TLC and nurturing garden care, while weeds, especially aggressive alien ones, should be yanked.

This weedy eggplant is native to the West Indies but has been spread all over the tropics. The fruits are used green in curries, sauces and salads. The fruits are very bitter and need to be blanched in several changes of hot water before using them. Some people love that bitter flavor and use them raw in salads. For more information on this and other tropical vegetables and herbs, check out the book "Ethnic Culinary Herbs" by George Staples of the Bishop Museum.

Heidi Bornhorst is the director of the city's five botanical gardens: Foster, Liliu'okalani, Wahiawa, Koko Marina and Ho'omaluhia. Write to her at The Honolulu Advertiser, P.O. Box 3110, Honolulu, HI 96802, or e-mail her at islandlife@honoluluadvertiser.com.