Curly onion

Questions about curly onion

Does curly onion need sun or shade?

Curly onion grows in full sun (6 or more hours of direct sun a day).

It wants dry, sharply drained soil, on the lean side, with no feeding, and little watering once settled.

What zones does curly onion grow in?

USDA zones 4 to 9. It is hardy to zone 4, which means it survives winter nights down to about −20 °F (−29 °C).

Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.

When does curly onion flower in my zone?

In zone 5 it flowers late July to early September. As a summer flower it moves about half a week for every zone: earlier where it is warmer.

Worked out from Hopkins' bioclimatic law: spring arrives about four days later for each degree of latitude north, and one zone is roughly two degrees. A warm spring or a cold one moves any garden two weeks either way.

How far apart should curly onion be planted?

10 in (25 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 12 in (30 cm), so a group knits into one patch.

It grows 10 in (25 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.

How many curly onion plants do I need?

At 10 in apart, set out in staggered rows:

• 17 to fill 10 square feet (about 1 m²)
• 13 for a single row 10 ft (3 m) long
• 55 to fill a 4 × 8 ft bed on its own

In a mixed border, plant it as runs of three or five along the front (or one even row, in a formal bed).

In the bed above, the planner used eight in two groups.

Is curly onion poisonous to dogs and cats?

Yes: moderate toxicity to dogs, cats and horses. Like all onions, it can damage red blood cells in dogs, cats and horses if eaten.

Is there a pet-safe plant like curly onion?

These come closest to doing what curly onion does, and no toxicity is recorded for them:

• Wall germander: the same job in a bed, the same size and the same colour; flowers late June to early August, keeps its leaves in winter.
• Sea thrift: the same job in a bed, the same size and the same colour; flowers early May to mid June, keeps its leaves in winter.
• Bloody cranesbill 'Max Frei': the same job in a bed, the same size and the same colour; flowers late May to early August, wants average soil.

Matched the way the planner's Swap button matches plants: the same job in a bed, then size, then flowering time.

What flowers after curly onion?

Curly onion is over by early September. These start as it finishes and carry the same spot on, so it never goes flat:

• Garden chrysanthemum: from mid September to late October, 24 in tall.
• October daphne: from mid September to late October, 8 in tall.
• Meadow saffron: from mid September to mid October, 6 in tall, to stand in front of it and cover its fading stems.

What does curly onion look like in winter?

Curly onion dies down to the ground and there is nothing to see until spring. The old stems can be cut in autumn, or left until spring as shelter for overwintering insects.