Tradescantia sillamontana aka Velvet Plant

Tradescantia sillamontana is an evergreen perennial in the spiderwort family, Commelinaceae. Common names include cobweb spiderwort, white velvet, and white gossamer. It comes from dry parts of northeastern Mexico, including Nuevo León. Its name refers to Cerro de la Silla near Monterrey. Garden plants grow about 0.5–1 foot [0.15–0.30 metres] tall. They spread about 1–1.5 feet [0.30–0.46 metres] wide. The RHS gives upper limits of 1.6 feet [0.5 metres] for both dimensions.

Dense branches form a low groundcover with upright or trailing growth. The thick, fleshy green stems may bend in a zigzag. White hairs cover both stems and leaves. The folded, oval leaves range from olive to grey-green. Their soft hair coat gives them a silver look. Purple tones may show in sun, with reddish-purple beneath. Leaf bases clasp the stems. Leaves alternate in two rows, each across from the next. Growth is slow, and pinching stem tips makes plants bushier.

Pink to magenta flowers open in summer above the hairy foliage. Each flower has three petals and a broad, shallow shape. Blooms measure about 0.06 feet [0.02 metres] across. NC State describes single flowers near the stem tips. The RHS describes clusters at the ends of stems. Plants can self-seed, which may become a nuisance. Cutting back after bloom limits seed spread and may prompt more flowers.

Grow it in bright, filtered light indoors or partial shade outdoors. It tolerates full sun when soil holds enough moisture. Strong midday sun can scorch the leaves. Use soil that drains well, with loam as a useful base. It accepts acid, neutral, or alkaline soil. Water moderately during growth and reduce watering in winter. Plants tolerate drought, but excess water can cause root rot. NC State lists USDA zones 10–12; the RHS rates it H1C. In cooler places, grow it as an annual or container plant. Stem-tip cuttings offer a way to make new plants.

Its silver foliage suits pots, hanging baskets, and rock gardens. It also serves as a low accent or groundcover. Watch for aphids, mites, thrips, mealybugs, and vine weevils. Snails and caterpillars may also feed on plants. The RHS reports few disease problems under suitable conditions. Leaves can irritate the mouth and stomach if eaten. This risk applies to both people and pets. Cats may also develop diarrhoea and become lethargic. Handling can cause red, irritated skin, so wear gloves.