Coleus argentatus aka Silver Spurflower

Coleus argentatus, or silver spurflower, belongs to the mint family. It comes from Queensland and northeastern New South Wales, Australia. Its native range has a subtropical climate. Gardeners may also know it as Plectranthus argentatus. This evergreen subshrub grows fast and forms a spreading bush. It keeps its leaves where the climate stays warm.

Garden plants reach about 2–3 feet (0.6–0.9 metres) tall and wide. RHS gives an upper size of 3.3 feet (1 metre) each way. Plants take two to five years to reach full size. Dense silver hairs cover the square stems. The simple leaves grow in opposite pairs along them. Each leaf has an oval shape with a pointed tip. Scalloped edges frame the soft, felt-like surface. The leaves look green-grey beneath their coat of silver hairs. They can reach about 0.33 feet (0.10 metres) long.

Small flowers appear in July and August, above the foliage. Their fused petals form pale blue-white tubes. Upright terminal racemes reach about 1 foot (0.3 metres) long. Each bloom reaches about 0.04 feet (0.013 metres) in length. Bees visit the flowers. Though the flowers add summer interest, gardeners grow this plant chiefly for its leaves. The silver foliage also supplies material for cut arrangements.

Give it partial shade or bright light without direct sun. Under glass, protect the leaves from hot sun. It grows in loam or sand with good drainage. RHS lists acid, neutral and alkaline soils as suitable. Keep the soil moist, but avoid leaving it soggy. The plant tolerates some dry soil once growing. Its outdoor hardiness range covers USDA zones 10–11. RHS rates it H1C for UK conditions. In colder places, grow it as a summer annual or houseplant. Beds, borders, foundation plantings and large patio pots suit its spreading form.

Routine pruning is not needed, according to RHS. Grow new plants from seed or stem cuttings. Pest and disease trouble is often limited. Still, check for scale, mealybugs, aphids and whiteflies. Slugs may also cause damage. Too much water can lead to root rot. Leaf spot can occur as well. Deer seldom damage the plant, which adds value in exposed garden beds.