Hummingbirds have a weakness for red flowers. And I have a weakness for hummingbirds. So even though red is not my favorite color, I always try to grow a few red flowers in the garden — just for the hummingbirds. Some years it’s salvias and hibiscus. Others I may have fuchsias or geraniums. The only plant with red flowers that’s earned a permanent place in my garden is Crocosmia ‘Lucifer’.
What to Know about Crocosmia
These statuesque perennials are native to South Africa, where they grow wild in moist, grassy areas. The plants have sword-like foliage with vertical pleats, and tubular flowers on wiry, arching stems. There are six species of crocosmia and many cultivated varieties that offer different heights, flower sizes and flower colors.
Like crocus and gladiolus, crocosmia grow from flattened, bulb-like corms. The corms are winter hardy in zones 7-11, and most varieties are also hardy in zone 6. Bright red ‘Lucifer’ is the only cultivar that can survive zone 5 winters. Other crocosmia cultivars that are popular with home gardeners include ‘Emberglow’, ‘Emily McKenzie’, ‘George Davison’ and ‘Solfatare’.
Where to Plant Crocosmia
Crocosmia’s brilliant red flowers add midsummer excitement to mixed perennial borders. And even when the plants are not in bloom, their stiffly upright foliage adds textural interest. Crocosmia is a particularly good companion for ornamental grasses and daylilies. Tight on space? Plant the corms in pots for a burst of late summer color that can be added to beds, borders or larger containers.
How to Plant Crocosmia
It’s important to plant the corms in well-drained soil. Though crocosmia grow best when they receive consistent moisture, they dislike heavy soil and will not tolerate soggy conditions.
If you garden in a relatively cold part of the country, plant your crocosmia in a spot that’s warm and in full sun. In moderate climates, it’s best to plant the corms 4-5” deep. In colder zones, planting them an inch or two deeper will provide some additional insulation.
Caring for Crocosmia
In northern areas, it can take a couple years for crocosmia to get well established. Once they do, most cultivars, including ‘Lucifer’, develop into fairly large clumps. There are a few species of crocosmia that are considered invasive, so if you garden in the deep south or Northwest, only plant named cultivars.
Hummingbirds love the tubular flowers of crocosmia, especially when they’re red. Fortunately, deer and rodents usually leave these plans alone. They are also rarely troubled by insect pests or disease.
When the flowers finish blooming, snip off the flower stalks at ground level and allow the leaves to continue growing. The foliage will die back naturally in the fall. When growth resumes in the spring, cut the dead leaves back to a height of 4 to 5”.
When crocosmia is growing vigorously, the corms can multiply quite rapidly. If the plants are robust, yet flower production decreases, it’s probably due to overcrowding. As the corms multiply, they also push their way up toward the soil surface and this can cause the stems to get floppy. Dividing the clumps every 3 to 4 years and replanting the corms at the proper depth, restores vigor and improves flower production.
The best time to divide crocosmia corms is fall. Start by cutting back the leaves to 5”, then dig up and pry apart the clump, taking care not to break off the young shoots. Replant smaller clumps, making sure to set the corms at a depth of 5 to 6”.