Gilia capitata aka Blue Thimble Flower

Gilia capitata is called globe gilia or blue gilia. It belongs to the phlox family, Polemoniaceae. Its native range runs from Alaska through the western United States. It has also reached the eastern United States through introduction. Garden sources describe it as an annual herb. Kew records its life form as annual or perennial. It grows fast and has an upright, branched form.

Garden plants reach about 1.6–2 feet (0.5–0.6 metres) tall. Their spread can reach 2 feet (0.6 metres). Reported height extremes reach 3.5 feet (1.1 metres). Strong green stems have smooth or glandular surfaces. The gray-green leaves bear fine hairs and narrow divisions. They are twice pinnate, giving the plant a light texture. Leaves grow at the base and alternate along the stems. Those near the stem tips are smaller than lower leaves.

Round flower heads rise above the finely cut leaves. Each head holds about 50–100 small, tubular flowers. Their shades range from pale blue to blue-violet. Each flower has five petals and stamens that stand out. The heads measure about 0.07–0.13 feet (0.02–0.04 metres) across. They have a light scent and draw bees and butterflies. Flowers appear from May to July. Removing spent heads may bring another flush of bloom. Small capsules follow the flowers, each holding up to three seeds.

Give this plant full sun and soil that drains well. It prefers dry, sandy or rocky ground. Loam and chalk also suit it. It tolerates clay with good drainage and some shade. It accepts acid, neutral and alkaline soil. Moderate soil fertility suits it, and it withstands drought. Avoid giving it too much water. The RHS assigns it UK hardiness rating H4. Sow seed where plants will grow in mid-spring. Plants may flower, set seed and die during summer heat.

Globe gilia suits borders, rock gardens and informal cottage gardens. It also fits gravel gardens and dry planting schemes. Its nectar adds value to gardens for bees and butterflies. Self-sown plants can help fill meadows and naturalized areas. It fares poorly where other plants compete strongly. Cut plants back once flowering ends. Garden sources report few pest or disease concerns. Neither source provides evidence for edible uses or toxicity.