Allium

With a flowering period from late spring into summer (for many of the species and cultivars) the ornamental onion is ubiquitous at RHS Chelsea. With good reason, as they add a different dynamic to a border, with their rounded heads hovering above other plants, either dotted through, or creating a naturalistic looking drift. Lower growing forms can be suited to a rock garden, or to flower before a neighbouring companion produces too much growth. Taller forms are good growing through purple sage  (Salvia officinalis 'Purpurascens') or growing behind Hylotelephium for example, as a good way of hiding the deteriorating foliage. Either way an essential component to a sunny border.

Allium now includes the old genus Nectaroscordum.