Fleshy stems and deep purple to metallic-violet leaves makes purple heart (Trandescantia pallida "Purpurea") a popular annual container plant or tropical groundcover. Tolerant of heat, drought and sandy soils, this succulent plant bears small three-petaled flowers in summer. Also called purple queen, it grows outdoors successfully in USDA zones 8 and warmer; a light freeze kills the foliage to the ground, but will rejuvenate from the roots.
Purple heart tolerates a wide range of bright light exposures. If soil is fertile and moist, it grows well with a full sun exposure: more than 8 hours of direct sunlight daily. It also tolerates lightly shaded locations or where dappled sunlight reaches leaves across the day when soil moisture is drier. Less than 4 hours of direct sunlight each day causes the purple leaf coloration to dull, stems to weaken or leaves to drop off.
Plant purple heart in any soil, whether sand, clay or loam. Acidic to slightly alkaline soils must remain moist and drain well for best growth and to reduce chances of stem rot. Sandy soils need much organic matter to sustain healthy-looking leaves, as it dries out quickly. Amend heavy clay soils with organic matter, too, to encourage better drainage, especially during wet, rainy bouts during the summer.
Although drought tolerant, providing one inch of irrigation to plants promotes even, continual growth in the growing season. To conserve water, withhold water until the leaves become curled or limp. In winter when sunlight intensity diminishes and temperatures are cooler, watering can be withheld. Provide one inch of water every 14 to 21 days until the vernal equinox, then resume the weekly watering schedule.
Use either a granular, slow-release fertilizer or water-soluble liquid fertilizer according to product label directions only during the spring and summer months. Over-use of fertilizer results in voracious growth of purple heart, leading to frequent pruning maintenance and increased need for watering. Do not fertilize in fall or winter. Adding a soil top-dressing of compost substitutes for artificial fertilizer applications.
This plant grows quickly and becomes strong when heat and soil moisture abound, often overtaking nearby plants or out-competing plants in container plantings. Prune back stems as needed to control size, but remove all clippings, as leaf and stem fragments may root to become new plants. Cuttings of stems taken in fall before frost root in water or moist soil and may grow as an indoor plant for transplanting outdoors next spring.
Some people may develop a rash when they come in contact with purple heart foliage. Contact dermatitis occurs most frequently during maintenance pruning as the sap from cut leaves and stems touches and dries on bare skin.