Allium nigrum multibulbosum is also known as Black Garlic or Flat Leaved Onion. The spherical flowers are white with hints of green, at the top of the straight stalks about 70 cm high. The stately balls of petals will punctuate the back of the border. Flowers May-June. Just dig a small hole about 10-20 cm deep, put the bulbs in and cover with soil then water. Please contact us for any other gardening advice.