A Guide to Planting, Growing, and Caring for Crocosmia Plants
From the best soil for planting to watering tips, two gardening experts share their advice.
Known for their colorful blooms and sword-shaped leaves, crocosmia plants, also known as coppertips, are beloved by gardeners for their flashy, fragrant flowers. "crocosmias are members of the iris family; blooms start in May and can continue all summer," explains Dr. Gladys Mbofung-Curtis, a plant scientist at Spectrum Brands Home & Garden. "Their blooms have a subtle saffron scent that intensifies when the flowers are dry, and their bright tubular flowers can attract hummingbirds, butterflies, bees, and other pollinators."
However, for as rewarding as having crocosmias in your garden may be, growing them can be tricky. "If they aren't planted in well-drained soil, the roots of crocosmia plants can rot," explains Samantha "Foxx" Winship, founder of Mother's Finest Family Urban Farms. "Handle the bulbs carefully when planting and make sure to get them from a reputable nursery."
When to Plant Crocosmias
According to Winship, spring is the best time to plant crocosmias because the soil is warm and the danger of frost is gone. "If you're experiencing cooler temperatures in your area, delay planting until the soil has warmed up," she says. "They'll bloom for five to eight weeks from midsummer to late fall."
How and Where to Plant Them
For optimal growth and flower production, Mbofung-Curtis says to plant crocosmias in full sun. "In overly shady conditions, the plants might strain for light, which causes them to flap over," she explains. If you live in a hotter climate, Winship suggests planting them in partial shade, so they will still receive sun exposure without the soil drying out. "To ensure the best blooms, choose a spot sheltered from cold and drying winds," she says. She also says that crocosmias thrive in slightly acidic soils that are well-drained and rich in nutrients. "Adding a thick, dry, organic mulch around plants can help retain moisture in the soil during growth while providing protection and warmth for corms [a vertical underground stem that acts as a food storage structure] in the winter," she explains. If you're located in an area with a hot climate and dry soil or that receives a lot of rain, she recommends growing crocosmias on a flattened, raised bed to ensure proper drainage.
If you aren't planting your crocosmia corms with the pointed tip facing up, Mbofung-Curtis says you're doing it wrong. "Plant corms with the pointed tip upward, six to eight inches apart, to a depth of three to five inches," she says. When planting in groups, she suggests increasing the distance between groups of corms to 18 to 24 inches to ensure they receive adequate airflow and light.
How to Care for Crocosmia Plants
Moist soil is key to growing a healthy Ccocosmia, which is why Mbofung-Curtis says you should water the plants once a week. "Remember, croocosmias do not grow well in water-logged soils," she says. "Water them weekly and early in the morning when the top of the soil feels dry."
A little maintenance goes a long way when cultivating crocosmia plants in your garden. "Prune spent blooms by cutting their inflorescences back to encourage new blooms," Mbofung-Curtis says. However, she advises not to prune the leaves of the plant after the flowers have bloomed, because they can photosynthesize and help your bulbs grow stronger next summer.