Ornamental Onion Comparison

Genus: Allium

The ornamental onion (Allium) family includes a selection European varieties and a Wisconsin native! They're noted for their grass-like foliage and round or drooping flower blossoms during summer. You may recognize its round, golf-ball size (globe shape) flowers.

The flower colors range from white to vibrant pink to purple, depending on the plant and time of season. In Wisconsin, they are summer-blooming perennials that begin in June or July and begin to fade in August depending on the season.

How to Use Your Ornamental Onions

They can be used in a wide variety of garden and landscape settings, including culinary and medicinal applications. They're versatile, and although their habits are typically similar, it usually comes down to flower color, heights, and pollinators that attracts growers. Here are some different ways you can grow them:

  • Rock Gardens (these plants thrive in well-draining soil. Rocky soils provide great drainage),
  • Border Front (interesting flowers attract attention/sturdy flower stems won't flop),
  • Cottage Garden (an informal planting where flowers take center stage. A romantic jumble of bulbs, annuals, perennials, flowering shrubs, and climbers),
  • Naturalized Area (the native Nodding Pink Onion, Allium cernuum, will self-seed and spread over large areas),
  • Pollinator Garden (attracts bees, butterflies, and more!)
  • Container Garden (not much room to spread and seed, one single plant will remain small),
  • Cutting garden (unique flowers, fresh or dried, add interest to any bouquet).

Pollinators & Wildlife

They contain a pungent aroma. Every Allium, especially the Wisconsin native, are well-known for being pollinator friendly. Whether you're looking at them at our nursery or in the mass planting in your yard, you can expect to see buzzing bees, visiting butterflies, and other small pollinators.

Our native onion is unique in that it leaves behind seeds in fall that are desirable to birds. Good news! Typically, nuisance wildlife, such as deer and rabbits, avoid onions.

Ornamental Onion Notes

Pruning: Ornamental onions are herbaceous perennials, meaning they die-back to the ground each season. It's the grower's choice whether you want to leave them up in fall to benefit other wildlife, clean then up in spring, or allow them to live naturally over the seasons.

Pests/Problems: Alliums in general have no serious issues. Bulb rot may occur in soggy or waterlogged sites and is noticed by squeezing the bulbs to feel if they are soft or mushy. Like most plants, there are a few cosmetic (non-lethal) issues that can occur, including (but not limited to) spider mites, snails, earwigs, etc...). You can alleviate these with over-the-counter treatments using insecticidal soaps.

comparing the summer flowers of ornamental onion allium at johnson's nursery in menomonee falls

Common Onion Perennials at Johnson's Nursery

These are the most appropriate for the average soils and landscape designs in our area. Long blooming plants with attractive foliage makes them the biggest sellers for us.

Common Onion Perennials at Johnson's Nursery

These are the most appropriate for the average soils and landscape designs in our area. Long blooming plants with attractive foliage makes them the biggest sellers for us.

nodding pink onion allium cernuum wisconsin natives catalog

** WI NATIVE **
Foliage Height: 18-24"
Foliage Spread: 8-12"
Bulbs can reach 36"
Flower Color: White-pink
Flowering: June-August

millenium ornamental onion allium rose purple flower perennial catalog

** AWARD WINNER **
Foliage Height: 12-18"
Foliage Spread: 12-18"
Bulbs can reach 18-24"
Flower Color: Rose-purple
Flowering: June-August

summer beauty ornamental onion allium at johnson's nursery catalog

Foliage Height: 16-20"
Foliage Spread: 12"
Bulbs can reach 24"
Flower Color: Lavender-pink
Flowering: July-August

allium summer peek a boo ornamental onion catalog

Foliage Height: 8-12"
Foliage Spread: 18-24"
Bulbs can reach 30"
Flower Color: Pink-purple
Flowering: July-August