As plant hybridizers are creating new varieties, more and more plants that were once grown solely as houseplants are making their way outdoors. One such plant family is the Cuphea genus. There are over 100 varieties of Cuphea, including a couple of species varieties that are useful outdoors as well as some hybrid varieties perfectly suited for use outdoors.
The first Cuphea that I remember seeing is C. ignea, commonly called the cigar plant. An unusual houseplant, it’s commonly displayed as a hanging plant, with small leaves and bright-red and yellow tubular flowers that resemble cigars. The small shiny leaves are produced in abundance, and this bushy, densely branched plant and its stems all produce the colourful blooms.
Hybridizers have developed outdoor varieties such as Proven Winners “Firecracker” in its “Vermillionaire” series. The plant has more vigour than the original species and its blooms are more prolific and larger in size.
Another is Cuphea hissopifolia, commonly called Mexican false heather. Although the plant might resemble heather, all Cuphea are members of the loosestrife family. The plant’s common name comes from its appearance; it is covered with innumerable small lavender-pink flowers, resembling large swaths of heather growing in warmer climes. This type of Cuphea is also a mounding, densely branched plant. The flowers are small and trumpet shaped and each blossom has six spreading petals. The most common colour is lavender pink, but there are also white and pink varieties. Proven Winners has a pink variety called “Lavender Lace” which is a hybrid whose blooms are larger than those of the species varieties.
Cupheas are actually woody sub-shrubs in their native habitats in southern North America and Central America. This is not unlike the loosestrife (lythrum) we grew before it was found to be an invasive plant and was put on the invasive noxious weed list. It had woody stems even though it died back to the ground each winter. Cuphea is not hardy in our region, but has two great characteristics that make it popular: it is heat tolerant and it blooms from the time it is put out into the garden until fall frost cuts it down. Although it prefers its planting medium to be kept moist, once it is established, it will tolerate some drought without any adverse effects.
Cuphea demands full sun, and even slightly reducing the direct sun it receives will affect how it performs; it will become leggy and the amount of bloom produced will be reduced. Cuphea likes a well-drained soil and responds well to being fertilized throughout the entire growing season. It will grow about 50 cm high and has a spread of at least 50 cm. Although it is sometimes sold as a “basket stuffer,” the plant is a bit too large to be used as a filler in a mixed container. It is better suited to being used as one of the feature plants instead. With its dense growth habit, it will not allow nearby plants to encroach upon its space and if planted too close to its neighbours, they will suffer. When used alone in a container — either a hanging basket or one sitting on the ground — although it has a slightly trailing habit, its branches will not cascade enough to reach the ground.
Mexican false heather is usually grown from seed. Because in its native habitat it is an evergreen plant, it can be overwintered indoors. It should be potted in the fall, cut back severely and located in front of a sunny window where it will receive maximum direct sun. It is generally not bothered by insect pests and experiences few disease problems, making it a relatively easy plant to grow.
Cuphea is not a common plant and you might have to look for it in several places, but it is well worth the search. Connie Langerquist, head horticulturalist at the International Peace Garden, gave a talk on new and exciting plants at a Brandon Garden Club meeting and she strongly recommended it. I do too. Look for one to add to your garden — it isn’t too late!