Skill Level: Intermediate
Allium forrestii is one of our favourite ornamental onions. Rather than forming the typical onion orb, it produces clusters of nodding bells that dangle gracefully from slender, arching stems. In bloom it has a jewel‑like intensity—compact, upright, and unexpectedly elegant. Mature plants typically reach 10–12 inches tall and 6–10 inches wide, making it ideal for troughs, crevice gardens, and sunny, well drained borders where a pop of late spring colour is welcome.
This species thrives in full sun and sharp, gritty, free draining soil, echoing the alpine screes and open slopes of its native range in Yunnan and Sichuan. We grow ours as part of our clay pot garden. It is reliably hardy in Zones 5–8, provided winter moisture is not excessive. In the garden, A. forrestii blooms in late spring to early summer, often just as early bulbs are fading and before the high summer alliums begin.
Our Seed Germination Experience
In our experience, A. forrestii seed requires intermediate skills because of its short period of cold stratification to break dormancy. The seeds are orthodox, but with a caveat: although they tolerate drying, viability drops noticeably after 12 months, so sowing within the first year is strongly recommended for best results.
We sow our seed in February in an unheated Zone 8 greenhouse, allowing the remaining winter chill to provide the cold period this species expects. This can be duplicated in the fridge without a drop in germination rates. Germination begins in under 30 days at temperatures near freezing, with seedlings left to grow as temperatures rise through spring. They remain in their pots during the first season, forming small but sturdy bulbs by autumn.
From seed to bloom, A. forrestii is pleasingly efficient for an alpine species—typically flowering in its second or third year, depending on growing conditions.
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