This grower is sure of this plant identification.
Ornamental allium, Onion
Allium aflatunense (Ornamental allium). This is a large species ranging in colour from reddish-pink to a deep purple. It will form a perfectly round ball of colour which is mostly attractive to butterflies.
You should plant your bulbs 4-6ins apart and 4-5ins deep in a well drained soil. Give them full sun which is recommended for best blooms, but they will perform well in light shade as well. These plants are very effective planted in large groups of 10 or so.
Border, beds. Ornamental vegetable.