Nasturtiums

Family: Tropaeolaceae (Nasturtium family)
Genus: Tropaeolum

Whoops, it’s happened again. Every year at this time I fall victim to a particular malady as I wander through garden centers looking for bargains or maybe just a little inspiration. There are always a number of fresh new plants set out at mid-season, and often they are quite unusual. This seems to be the time when growers stretch their offerings beyond the garden standards available in spring. They might be testing the waters. Perhaps they think if it sells now, it might take root in the hearts of gardeners and move off the shelves quickly next spring. But my heart is available always, and hence I’m vulnerable to the malady I mention: I find myself captivated by some beautiful plant that calls to me now. Buy me, it sings from the garden-center shelf. Ignore the fact that your beds are full already. Ignore constraints posed by budgets and time. Buy me. Take me home and plant me right now.

This year, the plant I think I hear singing to me has caused me to reconsider my opinion of nasturtiums. I gave up the common annual nasturtium, Tropaeolum majus, years ago, when I realized it seemed more interested in singing to aphids than in appealing to me. Even though lovely new flower colors were introduced every year, I enjoyed them only in other people’s gardens or in commercially available salad mixes. The leaves and the flowers are edible, and they share their common name with another spicy plant: Nasturtium officinale, or watercress.

Where they are native—in South America—members of the Tropaeolum genus are typically climbers, a habit that’s clear from the way T. majus sprawls through the flower bed and twines up through other plants if given a chance to grow by the gardener and if ladybugs and birds help it throw off the certain onslaught of aphids. Tropaeolum peregrinum is in fact known as the canary bird vine—it’s an annual climber that grows quickly to 12 feet in one season here, if it’s the sort of summer we’re experiencing this year. It does not grow so robustly during years when our spring and early summer are cool and rainy. In any year, however, it’s well worth growing from seed in late April for its deep-green leaves and its yellow flowers with traces of red, flowers that really do look—from a distance—like little canaries. T. peregrinum seems not as susceptible to aphids as T. majus—or perhaps it’s just that the years I grew mine, my hose and I took special care to blast the aphids off before they had a chance to settle in. A bit of rubbing at them with gloved fingers was required, too, as I recall.

I would like to spot another canary bird vine—sometimes it’s called a canary creeper—this year, since I didn’t start seeds this past spring. What I’ve found instead, however, is a local, in-ground example of the plant that stole my heart in the garden center. It is Tropaeolum speciosum, and unlike T. majus and T. peregrinum, it is a tuberous perennial, rated dependably hardy to USDA Zone 8. A gardener on the south side of Bellingham reports hers is in its eighth year and will likely be in full bloom by mid-August.

If T. majus is the common nasturtium, then T. speciosum must be the royalty of the clan. It is really stunning, with dark leaves that appear almost blue and very beautiful red flowers that are reportedly followed by berries of blue encased in dark red. It is much admired and widely cultivated in Europe, where it is known as the flame vine. Said to be tricky to grow and hard to establish, it is also reputed to be quite an enthusiastic rambler once it takes hold, winding through large hedges and completely covering small shrubs in one season. It has become a pest plant in New Zealand. Therefore, please note this serious disclaimer: because it is a perennial likely to be hardy here and because it is said to appreciate the climate we have, grow it with awareness and proceed with caution. Many noxious weeds started their local careers as much-admired ornamentals.

If you do decide to give it a watchful try—I have, and I’ll keep you posted on progress if you wish—you can find small starts now, with no tuber yet developed. There are also a few mail-order sources that offer very limited numbers of tubers for spring planting. Give your T. speciosum conditions just like those you’d provide to clematis. The roots and base of the plant should be in cool shade; and the top should receive full sun. Keep an eye on it, and be prepared to keep it in bounds and perhaps prevent it from going to seed. Be ready with the hose, too, and put yourself on aphid alert. Remember to blast them off before they have a chance to establish a colony. Don’t overwater your flame vine—all the nasturtiums have low water needs—and certainly don’t overfeed it, or you’ll have lush foliage and few flowers. and the flowers of T. speciosum are what will certainly steal your heart, if it’s anything like mine.