Why some leaves are purple underneath
Many houseplants have leaves that are green on top and purple, burgundy or magenta on the underside. The colour comes from pigments called anthocyanins. One commonly suggested role for them is helping leaves in shady forest floors make use of light that passes through, but the exact reasons vary by species. For gardeners, the practical effect is a plant that looks different from every angle, which is especially striking when stems hang or trail.
Trailing plants with purple undersides
- Wandering jew / zebrina (Tradescantia zebrina): Silver-striped green leaves above and glowing purple below. A classic hanging basket plant.
- Purple heart (Tradescantia pallida): Deep purple on both sides, so it is more purple all over than underside-only.
- Tradescantia ‘Nanouk’ and related hybrids: Pink, purple and green patterns, with trailing stems.
- Purple waffle plant (Hemigraphis alternata): Puckered metallic leaves with purple undersides. It can trail, but is often more compact.
- Purple passion plant (Gynura aurantiaca): Fuzzy leaves with purple hairs. Stems can droop or be trained.
These are good companions to the plants in indoor plants that grow downwards.
Upright or clumping plants with purple undersides
- Moses-in-the-cradle (Tradescantia spathacea): Rosette of sword-shaped leaves, dark green above and purple below. Also called oyster plant or Rhoeo. See oyster plant care indoors and is Rhoeo an indoor plant.
- Prayer plants (Maranta, Calathea): Patterned leaves with purple or magenta backs that fold up at night. They generally prefer humid, bright indirect conditions. See the calathea care guide and Is a peacock plant a prayer plant?
- Peperomia ‘Napoli Nights’: A compact, slow-growing peperomia with silvery leaves and a reddish or purple underside. See Napoli Nights plant care.
- Persian shield (Strobilanthes dyerianus): Iridescent purple foliage, usually with a metallic sheen.
- Purple shamrock (Oxalis triangularis): Triangular purple leaves that fold at night. See Is Oxalis triangularis an indoor plant?
Tradescantia care in brief
Most tradescantia like bright, indirect light, which also brings out the strongest colour. In low light, stripes and purple tones can fade and stems become long and sparse. Water when the top of the soil begins to dry, and avoid leaving the pot in standing water. Trimming the tips encourages bushier growth, and cuttings usually root readily in water or moist soil. Some tradescantia tolerate a little direct morning sun, but strong afternoon sun may scorch leaves.
Keeping the colour strong
- Give bright, indirect light.
- Rotate the pot so all sides get light.
- Avoid overfeeding, which can lead to greener, less colourful growth.
- Prune leggy stems to refresh the plant.
Safety
Some of these plants can irritate skin. The sap of tradescantia, including oyster plant, can cause rash in some people, so consider wearing gloves when pruning. Tradescantia is generally listed as mildly toxic or irritating to cats and dogs, and other plants on this list have varied safety records. Keep all of them out of reach of pets and children and check each plant against a trusted source such as the ASPCA list. If anyone has eaten a plant or shows symptoms, call a vet or poison helpline.
FAQ
What plants have purple leaves on the underside?
Tradescantia (zebrina and spathacea), prayer plants, purple waffle plant and purple passion plant are common examples.
Do tradescantia like sun or shade?
Usually bright, indirect light. Too little light dulls the colour; harsh sun can burn leaves.
What are examples of purple trailing indoor plants?
Wandering jew, purple heart and tradescantia hybrids are widely grown.