Cast-iron plant (Aspidistra elatior) is an herbaceous perennial that has earned its reputation as a nearly indestructible houseplant, though it's also hardy outside in USDA growing zones 6 to 11. It has arching deep-green glossy leaves and is so undemanding that it survives neglect that would easily kill lesser plants. Cast-iron plant practically grows in the dark, making it an excellent choice for those difficult-to-fill areas in deep shade.
When grown outdoors, it produces creamy purple flowers near the base of the plant, but the blossoms usually do not appear with indoor plants.
|Botanical Name||Aspidistra elatior|
|Common Name||Cast iron plant, bar room plant|
|Plant Type||Flowering perennial, houseplant|
|Mature Size||24 inches tall and wide|
|Sun Exposure||Full shade|
|Soil Type||Indoor: Potting soil; Outdoor: Sandy, clay|
|Soil pH||5.5 to 6.5|
|Bloom Time||Early summer|
|Flower Color||Cream with maroon on inner surface|
|Hardiness Zones||6 to 11|
|Native Area||Taiwan, Japanese islands|
How to Grow Cast Iron Plant
For a gardener with a brown thumb, this sturdy, long-lasting plant can be used in areas where all else fails. It is always green and can handle deep shade under deck stairs or along foundations that receive almost no sunlight. This hardy plant thrives in very hot, dry summers and is not easily damaged by cold winters. Insects seem to leave it alone, and it very rarely is bothered by disease of any kind.
When used in outdoor landscaping, cast-iron plant is common as a ground cover under trees. You can also use it as a background plant in your flower bed or along with azaleas for a nice in-between filler plant. They feature upright, strappy leaves that grow from an underground rhizome. The plant has small purple flowers that only appear near the soil surface and are hidden in its foliage.
These are highly dependable, attractive, and tolerant plants. The vast majority of mistakes with cast-iron plants are caused by either too much water coupled with dark corners (they dislike waterlogged soil) or by direct sunlight, which will cause leaves to turn yellow, then brown, before they die. Older plants can often be rejuvenated from intact rhizomes, even ones that might seem to be dried out from lack of water. These are also great potted patio plants.
Keep cast-iron plants away from direct sunlight, which can burn the leaves. If you're using it as a houseplant, you can place it away from the windows or near north-facing windows. Outside, place cast-iron plants in a shady area that's away from direct sunlight.
If your cast-iron plant is a houseplant, use potting soil with a compost base with a pH value between 5.5 to 6.5. Outside, the plant can grow in sandy or clay soils.
Cast-iron plant is drought-tolerant, but it does need some water—just be sure not to overwater it, which can lead to plant death by root-rot. Let it dry out between watering, checking with your fingers to see if the soil is moist.
Temperature and Humidity
A. elatior can be grown in temperatures between 45 and 85 degrees Fahrenheit—they're not picky about temperature or humidity. If you're growing the cast-iron plant outdoors in a container, take it inside before the first frost to allow the plant to hibernate in slightly warmer temperatures.
Fertilize your cast-iron plant every two weeks with an all-purpose liquid fertilize during the spring and summer months. It's not necessary to fertilize during the fall and winter months. Only apply fertilizer after watering the plant to avoid burning the roots. Keep in mind that cast-iron plants grow slowly, even when fertilized.
Potting and Repotting
Repot every other year as needed, ideally in the springtime. As rhizomatous plants, cast-iron plants can tolerate less frequent repotting, even going as long as four to five years without potting. Look for when the plant has outgrown the pot, and its roots are growing over the edge.
Propagating Cast Iron Plants
Aspidistra plants propagate by division. To start a new plant, take pieces of the rhizome that include at least two leaves. Pot into pieces of the rhizome that include at least two leaves. Pot into fresh potting soil and keep moist and warm until new shoots begin to emerge. Although new plants are slow to grow, with some patience and time, the new plant will thrive.
Varieties of A. Elatior
There are three varieties of Aspidistra elatior:
- 'Okame,' also known as 'Variegata': Instead of deep green foliage, this plant has white and green variegated leaves.
- 'Ashahi': This variety develops white tips as the plant grows.
- 'Lennon's Song': The leaves have light green or yellow vertical stripes.
Common Pests and Diseases
Aspidistra elatior can be affected by leaf blotch, which presents as brown or black spots that continue to grow before the leaves fall off. Remove the leaves that are infected and use a broadband fungicidal on the plant.
Cast-iron plants can also be affected by mealy bugs, scale insects and spider mites. Separate healthy plants from those affected by the insects. To fight mealy bugs, use a compound containing neem oil, while scale insects can be attacked with systemically acting chemicals. To get rid of spider mites, wash away the insects with water and, if necessary, use neem oil.
Aspidistra Elatior. Missouri Botanical Garden
Clausen, Ruth Rogers, et al. Essential Perennials: the Complete Reference to 2700 Perennials for the Home Garden. Timber Press, 2015