Scilla verna aka Sea Onion

Scilla verna, or spring squill, is a small bulbous perennial. It belongs to the asparagus family, Asparagaceae. Its native range spans northwestern Europe to the western Mediterranean. It is native to Britain and Ireland, too. This plant grows in temperate regions. Other common names include spring-flowered squill and sea onion. Botanical synonyms include Tractema verna, Scilla umbellata, and Tractema umbellata.

The plant forms small tufts with narrow, linear leaves. Its deciduous foliage does not stay green year-round. The RHS describes plants reaching about 0.7 feet [0.2 metres]. Its broader height range spans 0.3–1.6 feet [0.1–0.5 metres]. Spread reaches about 0.3 feet [0.1 metres]. Plants take two to five years to reach mature size. Small violet-blue flowers open in early spring. Each bloom has a star-like shape. The flowers form a dense raceme or corymb.

Choose a sunny site with soil that drains well. The RHS also lists partial shade as suitable. The soil may stay moist, but must shed excess water. Suitable soils include chalk, loam, and sand. Acid, neutral, and alkaline soils all suit this species. It can grow in exposed or sheltered sites. The RHS gives it a UK hardiness rating of H5. This covers winter lows of 5–14°F [-15 to -10°C]. Plant bulbs at two to three times their own depth.

Spring squill suits grass plantings and gravel gardens. It also fits rock gardens, borders, and informal cottage gardens. The RHS lists it for wildflower meadows and wildlife gardens. Its small size suits low planting schemes. No pruning is needed, and pests rarely cause trouble. Anther smuts and virus diseases can affect the plant. To raise new plants, sow ripe seed in pots. Keep these in a cold frame, shaded and moist. Another option is to remove offsets in summer.

Treat spring squill as an ornamental, not a food plant. Its bulbs are harmful to people and pets if eaten. Keep them away from children and animals that might eat them. Wear gloves and other protective gear when handling the plant. The common name sea onion does not imply an edible crop.