I HAVE referred in the past to some of the best allium varieties (ornamental onions) for sunny or lightly shaded borders, one in particular a great favourite of mine sold as Allium ‘Christophii’.
This has huge rounded flower heads atop stout, two foot stems, each of which comprises a mass of star-shaped lilac-pink/electric blue blooms.
They glisten in direct sunlight and quiver with their own lightness and buoyancy even in the gentlest breeze, but they also dry spectacularly when cut as soon as the flowers have faded.
These dried brown seed-heads then look like a large drum-major’s drumstick in which the black onion seeds glisten and rustle ready for collection.
A planting of six bulbs will cost you less than £8, more than enough to make an impressive impact even on those who wouldn’t know a flowering onion bulb from a marigold.
Allium sphaerocephalum has a very different appearance to Christophii and is unequalled in providing extra interest in the late summer border.
With dense umbels of dark purple, bell-shaped flowers it is a versatile plant that prospers in sun or partial shade.
Allow it to grow up through low growing plants such as Cranesbill ‘Orion’, ‘Rozanne’ or ‘Jolly Bee’ for its foliage is often tatty and way past its best as flowering commences.
Those geraniums have exceedingly good foliage and the contrast between both works well.
For a strong sculptural statement, grow Allium sphaerocephalum with domes of lavender ‘Hidcote’ or Santolina chamaecyparissus (cotton lavender) and delight in the combination.
Alliums fall into two distinct groups for cultivation purposes.
Those sold in dry bulb form during autumn (and planted before the onset of winter) will grow through late winter and spring and after flowering, die down for the rest of summer.
These (including sphaerocephalum) generally prefer well-drained soils and sunny positions.
Those with rhizomes or slender bottle-shaped or cylindrical bulbs (chives) will need summer moisture (they detest dryness at their roots) dying down completely for winter.
See More: Allium Christophii, Cranesbill, Flower, Geraniums
