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Purple allium
Purple allium

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Moderate

Allium caeruleum

Blue Allium

Bulbs and bulblike plants, Perennials

ALLIUM

About 500 species, all from the Northern Hemisphere, many from the mountains of the West. Relatives of the edible onion, they are peerless as cut flowers (fresh or dried) and useful in borders; smaller kinds are effective in rock gardens. Bear small flowers in roundish, compact or loose clusters at ends of leafless stems that range in height from 6 in. to 5 ft. or taller. Many are delightfully fragrant; those with onion odor must be bruised or cut to give it off. Bloom in spring or summer, with flowers in white and shades of pink, rose, violet, red, blue, and yellow.

All prefer well-drained soil (preferably on the sandy side), enriched before planting with organic matter. In fall or spring, plant bulbs as deep as their heigh or width, whichever is greater. Space smaller species 4–6 in. apart, larger ones 8–12 in. apart. Cut back on watering or let soil go dry when foliage begins to yellow after flowering. Foliage dies to the ground, even in mild-winter areas. Lift and divide only after clumps become crowded.

Allium caeruleum

Cornflower blue flowers in dense clusters to 2 in. across on 1–2-ft.-tall stems. Late spring bloom.

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