Surprises from the garden and a Hawaiian souvenir

It's a poisoned gift of age: Surprises tend to be unpleasant and expensive. Fortunately there are still exceptions, many in the garden.

This summer something extraordinary came up in our tropical patch in front, with the banana and cannas and callas and flowering ginger. With its long, bladelike leaves, we figured the mystery plant was some lily relative, maybe in the iris family. It kept growing, to 5 feet tall. Then the flowers popped out.

The flower structure seemed right for iris: six tepals (a handy term for flower parts that might be either petals or sepals). But this was like no iris we had ever seen, with a striking combination of electric blue-purple and chocolate-brown mottling. The flowers only lasted for a day or so each, but they kept coming, all summer and into early fall.

The plant must have emerged from a dormant or concealed bulb that neither of us can recall. (These surprises are that better gift of age.) We might have picked it up at the San Francisco Garden Show - maybe from Annie's Annuals, always good for the unexpected. But when? How long had it been biding its time? And what was it?

Iris relative

Eventually we got around to checking out Peter Goldblatt and John Manning's "The Iris Family," one of those big lavish Timber Press books, from the UC library. Based on Goldblatt and Manning's description, we're calling it a neomarica, most likely N. caerula, a South American iris relative. The clincher was the flattened, leaflike stem from which the flowers emerged.

Neomaricas are known as "walking irises" because their stems bend to the ground, allowing young plants to take root, like walking onions'. Ours has shown no such inclination. Sunset says neomaricas will grow in zone 17, where we are, so we're probably not getting away with much. Still, it was an unexpected pleasure. Would that every memory failure were so rewarding.

Some plants we buy on speculation, not knowing whether they're going to thrive or die. This spring we bought a potted ilima (Sida fallax) at the Hawaiian May Day Festival in Pleasanton. We were just back from Kauai, where we had seen this shrubby yellow-flowered hibiscus relative growing on the cliffs above the seabird colonies at Kilauea Point National Wildlife Refuge. Ilima is the official island flower of Oahu and a popular source of lei flowers. We put it in a pot on the south-facing front porch and hoped for the best.

Well, here it is December and the ilima is still blooming. The little orange-yellow flowers are plentiful and inordinately cheerful. A University of Hawaii website says it blooms year-round; Sunset calls it a zone 23-24 plant, so it will stay in its pot in case of frost.

Scent of carrion

Ron volunteered to drive a couple of visitors to the airport one dark and stormy night, and received a surprise thank-you gift in the mail: root-ready cuttings of an unfamiliar succulent. This one had come the long way, from South Africa via South Dakota; it's a starfish flower, Stapelia grandiflora.

It's also called "carrion flower" and, in Afrikaans, aasblom. We refrain from further inquiry about translation here. When the charming, velvety plant bloomed on the office windowsill, Ron was ready to noodge Joe about taking out the garbage, then looked over her shoulder for the source of an odd, angry buzz - a housefly, marching over the 5-inch hairy orange flower that had just popped open, looking for the rotting meat it too had smelled. As the stench rose, we were moved to look up its habits in the wild.

Like the world's largest flower, Rafflesia arnoldii, our gift is pollinated by flies and attracts them with a stench that, en masse, has been known to attract vultures. Now we're prepared: When they bloom, our stapelias - four of them now - go outdoors to bask near Joe's carnivorous plant collection. One plant's meat is another plant's pollinator.

Joe Eaton and Ron Sullivan are naturalists and writers in Berkeley. E-mail home@sfchronicle.com.

This article appeared on page K - 2 of the San Francisco Chronicle