Its fragrance isn’t overpowering, but it is immediately and unmistakably identifiable.

Chocolate Cosmos

Many plants are invited into our gardens because they have attributes startling enough to get our attention. Then we find that once they are introduced into our landscape, they are just too startling—too dramatic, too fragrant, too colorful—to cohabit nicely with our other favorites. They may simply overwhelm their neighbors, or they may turn downright nasty and try to take all the space for themselves. I’ve had this experience with night-blooming jasmine (who spilled all that heavy cologne in the yard?!), with love-lies-bleeding (way too dramatic for its companions), and with Houttuynia cordata (how did it grow under that sidewalk overnight?). Others might have similar memories of bamboo, of snow-in-summer (great name and greater tendency to choke out everything around it) or of Bishop’s weed. So I’ve learned to be cautious when confronted with any plant that has the power to startle with color, growth habit, or fragrance.

One startling perennial well worth bringing home from the nursery or plant sale, however, is Cosmos atrosanguineus, commonly and quite affectionately known as the chocolate cosmos. This is a tuberous-rooted perennial, although of course it’s a cousin to the annual C. bipinnatus that is a much-loved staple in many of our summer gardens. Members of the daisy family, all 26 or so species of the Cosmos genus are native to Mexico and the southwestern United States.

C. atrosanguineus smells like chocolate. Its fragrance isn’t overpowering, but it is immediately and unmistakably identifiable. The color of its daisy-like, single blossoms is as rich as my favorite sweet, too; but rather than being “chocolate brown,” it is more of an oxblood red, neither too orange nor too purple. It is a well-behaved plant with an open form, growing to perhaps 30 inches. Its foliage is bright green and deeply lobed, not unlike that of its annual cousin. C. atrosanguineus is a good choice for foreground planting, where its fragrance is accessible. It is quite a conversation piece. Gaura, Linaria, Achillea, and Coreopsis are all fine companions, as is any plant with silver foliage.

The requirements of C. atrosanguineus are similar to many other perennials in your garden: full sun, regular but not excessive moisture, and soil amended with plenty of organic material. It is not vulnerable to any specific pest or disease. C. atrosanguineus will break dormancy relatively late in the spring but will grow quickly and bear flowers from June through September. Propagation is best done in very early spring, by carefully dividing the tuberous roots before growth begins.

Of course, there’s a drawback. C. atrosanguineus is only half-hardy in our area, which means that to be absolutely sure it will survive the winter, you must lift the tubers in the fall as you would with your dahlias. Growing your chocolate cosmos in a container and overwintering it in a sheltered garage or shed is another option.

C. atrosanguineus was chosen as the January selection because it is interesting and attractive, but also because while its blooms have the scent of chocolate, having it around won’t add any calories at all! In fact, I like to think that preparing my beds for C. atrosanguineus and other favorite perennials will reverse the effects of all that real chocolate that gets nibbled each holiday season.

Happy New Year!