Crocus vernus aka Spring Crocus

Crocus vernus is a small spring plant in the iris family. Gardeners call it spring crocus or Dutch crocus. It comes from mountain regions of Europe. Kew places its native range from the Alps to the western Balkans. Other garden sources give a wider range, including the Carpathians. It is not native to Britain or Ireland. It grows from a corm, though garden guides often call it a bulb.

Plants reach about 0.3–0.5 feet [0.1–0.15 metres] tall and wide. The RHS gives the smaller size; Missouri Botanical Garden gives the larger. Narrow, dark green leaves rise from the base. They start upright, then spread out as they grow. The leaves look much like grass. They turn yellow and die back after flowering. The plant then rests through its dormant season. Its small size suits the front of beds and borders.

The goblet-shaped flowers come in white or shades of purple. Missouri Botanical Garden lists April as the main bloom month. Its account also notes late March flowering in St. Louis. The display lasts about three weeks there. Flowers open in the morning and close at night. They may stay shut during rain or cloudy weather. Plant groups in lawns, rock gardens, or beside paths. They also suit spots beneath trees and sunny woodland edges. Plants can spread over time to form patches in grass.

Give plants full sun, though they also tolerate some shade. Use soil that drains well, with grit where needed. Avoid heavy clay and ground that stays wet. The RHS lists acid, neutral, and alkaline soils as suitable. Supply moderate water during growth, then reduce watering as leaves fade. Drier soil suits the dormant corms. Plant corms in autumn, and divide crowded groups every four or five years. Leave lawn foliage uncut until it yellows, about six weeks after bloom. Hardiness ratings are USDA zones 3–8 and RHS H6.

This crocus needs little care and no routine pruning. Divide clumps or separate small cormlets to raise more plants. Serious insect and disease problems are uncommon. Stored corms can rot. Birds and rodents may cause damage; squirrels can dig up new plantings. Deer tend to leave plants alone. The RHS warns that the corms must not be eaten by people or pets. It also advises gloves and protective gear when handling them.