For Coleus, Unpredictability Is Second Nature

By Adrian Higgins
Thursday, September 25, 2008

Coleus has had a long run in gardens and greenhouses since 19th-century explorers brought this garish, nettle-leafed plant back from Java to help satisfy the Victorian mania for tropical plants.

Like heliotropes and zonal geraniums, coleus got bumped off the A-list of plants to party with many years ago. Perhaps it was that all-too-familiar leaf of chocolate brown edged with apple green or the excessive use of coleus as bedding annuals. But today, you guessed it, the coleus is back with a vengeance, riding the crest of popularity for tropicals that so define the contemporary patio garden. Just as this craze has brought weird and wonderful bananas, cannas and taros out of the woodwork, the interest in coleus has created some wonderful versions.

In its 21st-century incarnation, however, the coleus goes beyond its tropical playmates in the sheer breadth of its variety. It is hard to imagine that something as trendy and delicate as the Line, acid green with the thinnest dark strip along the leaf's midline, is the same plant as Kathryn Rose, a bicolor of purple-black and hot pink that suggests, balefully, a river of lava.

Many of these varieties are new, and they have been eagerly developed and promoted by a few coleus adventurers across the country, not least Ray Rogers, a horticulturist and author in New Jersey who invited me the other day to Atlock Farm, the nursery of his friend Ken Selody in Somerset, N.J.

Rogers was staging Coleus Day in the pretty, English-inspired display gardens of Selody's nursery, and as someone who hadn't focused on this plant for six or seven years, I found some of these varieties truly mesmerizing.

Late in the season, they were full of robust, heat-coaxed growth but remained clean and attractive for the most part. Wine Country is a bright green with complementary red margins. Jo Donna has an underlying yellow-green leaf with heavily marked red venation, a striking effect. Max Levering has golden leaves with random crimson spots and is beautiful. Schizophrenia has a golden base heavily flecked with oranges and reds. Saturn is a delight, featuring maroon leaves with yellow-green centers.

Most of them were planted in a bed Rogers called "The Paintbox." Certainly nature has gone to town with the pigments with rare zeal. Rogers can't think of another single garden plant that is so varied and genetically unpredictable.

"The question I constantly get is why is there so much variability, and who knows," he said. "Obviously, it's explainable on the molecular or genetic level with all kinds of switcher genes that for some reason are extremely active in coleus." His new book on the genus, "Coleus" (Timber Press, $29.95), doesn't seek to explain this scientific mystery but revels instead in the diversity of the plant.

Perhaps more important, apart from enjoying coleus and pairing it with other plants, is what makes a good coleus. Rogers wants his yellow-leafed varieties free of gray tones and his red selections unmuddied by brown tones, and he is drawn to varieties that are shy to bloom and don't need a lot of pinching to stay bushy. Coleus flowers can be pretty blue bottlebrushes and they remind you of the plant's relation to mint, but flowering typically causes a decline in leaf ornament and general vigor.

One thing is certain: Coleus is the shape-shifter of the gardening world, a trait that is often magical and sometimes maddening. A branch may develop leaves that are quite different from the rest of the plant's. This can be used to advantage: You can snip off a mutant stem and root it as a new variety. In the case of one coleus, Careless Love, this variability is left to do its thing. Rogers showed me one plant of Careless Love that started out with a variegated leaf in maroon and lime but produced five other leaf decorations, including foliage in solid colors, flecked and a blushed green.

Gardeners call a mutation a sport, but with coleus it's just as likely that the variety you are growing is a sport itself, and an aberrant stem merely a desire of the plant to revert to its original look. "They're the king of variability," Rogers says.

With so many varieties (Rogers displayed 120 variants at the event), he pointed out that the notion that coleus is a shade plant no longer applies. "Most coleus like morning sun and afternoon shade, some like full blazing sun and some must have shade all the day," he said. If the light conditions are not right for a variety, it will tell you. If it's in too much shade, the colors get darker and lose their brilliance; if it's too sunny, the pigments bleach.

One of the beauties of growing coleus in pots is that you can move them to their optimum site. But planting them in the ground, in enriched and free-draining soil, allows you to incorporate them into displays that come into their own in September and October.

At Atlock Farm, Rogers had integrated various coleus into borders with purple fountain grass; a mounding yellow daisy named melampodium; the leafy, purple cordyline; and a dark, low-growing, massed tropical named waffle leaf, or hemigraphis.

The Line might show up in my garden next year. I see it in a border of partial shade alongside Chocolate, the prolifically self-seeding eupatorium, and one of the late-season salvias, perhaps the Mexican bush sage or the gentian sage.

I could see the warm orange coleus, Rustic Orange, in a pot with spiky angelonias and the trailing scaevola, both blue-flowered.

Rogers loves a coleus he grew from a sport that he has named Black Radish. It is a deep purple that has both blue and red in it so it goes with both hot- and cool-colored companions. To make the point, he positions a pot of it next to Sedona, a dark orange, and Freckles, with orange and yellow variegation.

I am drawn to an old variety that the Victorians knew: Pineapple Queen. Its lime-green foliage contrasts with its dark, almost black stems. Seeing it so full and well groomed in a clay pot, I wonder why coleus was left in the wilderness for so long. But then I remember something Rogers said early in the day: "There's an awful lot about coleus that defies answers."

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