Ornamental onion 'Purple Sensation'

Questions about ornamental onion 'Purple Sensation'

Does ornamental onion 'Purple Sensation' need sun or shade?

Ornamental onion 'Purple Sensation' grows in full sun (6 or more hours of direct sun a day).

It wants dry, sharply drained soil, of average fertility, and little watering once settled. Once settled in, it stands drought.

What zones does ornamental onion 'Purple Sensation' grow in?

USDA zones 4 to 8. It is hardy to zone 4, which means it survives winter nights down to about −20 °F (−29 °C).

Above zone 8 it struggles: the zones measure winter cold, but a plant's top zone usually means the summers are too hot or the winters too mild for it to rest.

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

When does ornamental onion 'Purple Sensation' flower in my zone?

In zone 5 it flowers late May to early June. As a spring flower it moves about a week for every zone: earlier where it is warmer, later where it is colder.

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 ornamental onion 'Purple Sensation' be planted?

8 in (20 cm) apart, from the middle of one plant to the middle of the next. That is about its full width, so each plant keeps its own outline.

It grows 2½ ft (75 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.

How many ornamental onion 'Purple Sensation' plants do I need?

At 8 in apart, set out in staggered rows:

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

In a mixed border, plant it as one at a time, repeated along the bed at intervals; a slender one reads better as a clump of three.

In the bed above, the planner used five in five groups.

Is ornamental onion 'Purple Sensation' poisonous to dogs and cats?

Yes: moderate toxicity to people, dogs, cats and horses. Like all onions, it can damage red blood cells in dogs, cats and horses if eaten. Eating the bulbs in quantity can also upset a person's stomach.

Rated from NC State Extension. Where references disagree, the more cautious rating is used.

Do deer eat ornamental onion 'Purple Sensation'?

Mostly not. NC State lists it as resistant to deer and rabbits. No plant is proof against a hungry deer in a hard winter, but this one is low on the menu.

Will ornamental onion 'Purple Sensation' spread?

It seeds itself about; the risk of it taking over is moderate. Self-seeds if the seed heads are left standing. Cut them off after flowering to prevent seedlings.

What can I plant to hide ornamental onion 'Purple Sensation''s leaves after it flowers?

A bulb's leaves have to be left to yellow for about six weeks after flowering, to feed next year's flowers. Plant it among perennials that come up late and spread wide, and they grow over the leaves as they fade:

• Catmint 'Walker's Low': 24 in tall and 2½ ft wide, a recorded partner, in flower mid May to mid September.
• Peony: 3 ft tall and 3 ft wide, a recorded partner, in flower late May to late June.
• Daylily: 2½ ft tall and 24 in wide, in flower late June to early August.

What does ornamental onion 'Purple Sensation' look like in winter?

Ornamental onion 'Purple Sensation' is underground: it dies back after flowering and waits as a bulb until spring. Mark where it is, so a fork does not find it first.

Is ornamental onion 'Purple Sensation' good for bees and butterflies?

Ornamental onion 'Purple Sensation' is visited by butterflies.