— Perennial alliums are hardy to around -20C and can be planted straight outside in the spring.

— Soak the roots in water for 3-6 hours prior to planting.

— Plant the roots with the crown or buds just below the soil surface. Plant directly into a weed-free space in borders or pot up and grow on first to transplant as a potted plant later in the season.

— Plant in free-draining soil in borders or containers in full sun. If planting in containers, you can use multipurpose or soil-based compost.

— Space the plants 15-25cm apart from each other.

— Water-in after planting and keep hydrated when in growth in the first year.

— Read further general instructions about planting bare-root perennials