The garden’s transition from late spring into early summer can be spectacular when awash with flowering ornamental onions known as Alliums.
For years the most popular ornamental onion was Allium ‘Purple Sensation’. This bold, round headed pom-pom onion, some 70 cm. tall flowers at the time many gardens have a gap between the bright colours of spring and the start of the taller-growing perennial flowers of summer. When planted in bold drifts amidst the emerging perennials and ornamental grasses it stands bold and powerful, the perfect companion of yellow flowering euphorbias and flowering shrubs such as Viburnums and Deutzia.
Allium ‘Purple Rain’
Time moves on and every year I try new bulb introductions including alliums. As good as ‘Purple Sensation’ still is, I have two new ornamental onions that have become my standard choices. Allium ‘Purple Rain’ is a great improvement. Slightly taller growing, its round flower heads are larger and more open. It is a crossing between ‘Purple Sensation’ and Allium christophii. Christophii ( Syn. Allium cristophii) is a wild species with very large, open flower heads in a delicate shade of amethyst. Itself brings drama and structure to late spring borders and I consider it essential. Its character is now to be seen in the much taller and stronger coloured Allium ‘Purple Rain’.
Allium purpureum with Allium nigrum
Allium purpureum has smaller, half-round flower heads in a dark shade of purple. I regularly plant it amidst emerging ornamental grasses. Allium shubertii has a larger, more dramatic flower than Allium christophii; if that was possible. When crossed with Allium purpureum it has produced a truly bold improvement called Allium ‘Miami’. I am growing it for the first time this year and definitely want more next year.
Allium ‘Miami’
All ornamental onions remain attractive after flowering as their flowers fade and turn into dried seed heads. These structures can persist in the border for many months. Seeding can occur but is usually something to be welcomed.
Alliums come in a wide range of options, but these two: Allium ‘Purple Rain’ and Allium ‘Miami’ are well worth your while giving a go.
