Heliotrope

Family: Boraginaceae (Borage family)
Genus: Heliotropium
Species: arborescens or peruvianum

We all enjoy flowers that have a sweet fragrance. I think that’s why peonies are such favorites: they smell as good as they look. But their bloom time is short, and over by summer. What can we plant that has a continuous show of pretty flowers with a sweet scent that lasts well into fall?

Roses are perennial favorites, but many of them bloom intermittently and a few of the new ones have no scent at all. Besides, they take lots of care. We may be unwilling to give them what they need or unable to provide them with enough space to grow. So we choose a good-looking little plant that’s scaled just right for containers and we grow it in a hanging basket outside a window or in a pot by the door so we can appreciate its flowers and fragrance all summer.

Like many traditional cottage-garden flowers, heliotrope was prized by our grandmothers. For more than a few years it was hard to find in the marketplace but now it’s available just about everywhere. There are named varieties galore, with flowers in white and pale lavender. But I prefer the species, the old-fashioned kind with dark green, crinkled leaves and deep purple flowers. It’s most dependable, both in ease of care and reliable fragrance. Reminiscent of vanilla, the heliotrope’s scent gave rise to its common name used years ago: the cherry-pie plant.

Heliotrope has also been called “turnsole,” after its tendency to turn its flowers and leaves toward the sun over the course of each day. And at night it readjusts itself to face eastward, to be ready for sunrise. That tendency is at the root of the name heliotrope, too. It means to move with the sun.

In fact, heliotrope wants plenty of sunlight, at least through mid-day. The positioning it prefers is full sun in the morning but some shelter in the late afternoon, lest its leaves burn. Beyond that, it appreciates rich soil kept evenly moist—easy to manage, in a container—and regular feeding with a diluted, water-soluble fertilizer that’s higher in phosphorus than nitrogen. Look for a formulation that “encourages blooms.” The one I use is 10-60-10: something I would never apply to plants in the open ground, but it suits my containers just fine. In the full heat of summer, I water my heliotropes every day and give them a feeding once each week. That’s one of the nice things about growing pretty plants in containers. Even in times of drought, there’s plenty of water left over from household use to keep the plants happy, and they can be fed extravagantly so they’ll put on their best show. My heliotropes will be tuckered out by late September and they’ll end up in the compost pile to make their contribution to next year’s garden that way. Yes, I could take cuttings. And yes, I could go to the trouble of trying to keep them alive indoors. But neither is worth the trouble, particularly when I can buy new starts next spring for less than 2 dollars at any nursery center I care to visit.

Heliotropes get along fine with other plants in containers, so long as they’re adequately fed and frequently watered. They don’t respond to crowded conditions by developing powdery mildew, and they’re not prone to pests. What they do require is frequent pinching when they’re young.

It may seem heartless, but pinch them anyway. We know that pinching stimulates growth, and that lesson is particularly true where heliotropes are concerned. If you don’t steel yourself and do it, you’ll end up with a spindly plant with one or two long-lasting flower heads, and that’s it.

There are two approaches to pinching a heliotrope. One is to remove side shoots until the plant attains the height you have in mind—it might make it to 20 inches—and then start pinching back the top growth. This is not what I do, because I prefer bushy plants. My technique is to pinch back the tips all over the plant early on, which forces lots of new side growth. I wait longer for flowers, but I get more of them eventually. Removing faded blooms promptly results in a continuous show of pretty flowers starting in July and lasting till fall. Their fragrance is heavenly.

Nothing about the heliotropes we grow here can turn invasive. There is a creeping heliotrope—Heliotropium amlexicaule—that has become a plant pest in some warm-winter areas of the world. It’s caused problems by invading forage fields, because it’s poisonous to cattle. That attribute is shared by Heliotropium arborescens—all parts of the plant are poisonous and will cause gastric distress in humans and animals. So just enjoy its scent and don’t eat it. Turn to a real cherry pie for that pleasure, another of summer’s favorite treats.