Fall Planted Bulbs - Alliums
The allium, or onion, family contains the familiar onions, garlic, shallots and leeks. However, not all of them belong in your vegetable garden. Ornamental alliums with their large, colorful, and in some cases, oddly shaped flowers are stars in your borders.
Ornamental alliums look a great deal like regular onions. They grow from bulbs which look and smell like onions and have strappy foliage like onions. The biggest difference is the size of the plants and their flowers. Depending on the variety they can grow to 3 feet high with flowers the size of baseballs. Other varieties are shorter with flowers that droop (nodding onions) or have stringy petals (hair allium). My personal favorite are the drumstick allium with smaller flowers that look to me like eggs.
Alliums are native to the Northern hemisphere so they have a large hardiness range from planting zone 3 through 9. Most ornamental alliums are hardy from zones 4 through 8. They are planted in the fall after the weather and soil cools but before the soil freezes. Planting your allium before the ground freezes gives them a chance to grow some roots and get established before winter sets in. The rule of thumb for planting depth is three times as deep as the width of the bulb. Plant the bulbs like you would onions, with the roots pointing down.
Ornamental alliums should be grown in full sun and in well-drained soil. They aren't susceptible to many diseases or pests but they are sensitive to moisture and will rot in soggy soil. Speaking of pests, allium are deer resistant. Deer don't care for their onion taste or smell.
Depending on the variety alliums can bloom in the spring (large globe allium) or summer (drumstick, nodding and hair allium). There is no need to deadhead them. They only bloom once. The flowers can left on the plants when they are exhausted. The seedheads are attractive and can be used in dried arrangements. Keep watering the foliage to keep it alive and making food for the bulb which is needed for foliage and flowers next year.
Every 3 or 4 years, you will notice that your allium aren't blooming well. They are telling you that it's time to divide them. Carefully dig up the bulbs and separate the bulblets on the sides. Replant them in another area of your garden until they have reached blooming size in a year or two.
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© 2014 Caren White