The Garden Club August 3, 2007

Allium senescens and Allium senescens Glaucum

Onions - Not Just for Cooking
If someone were to say to you that they just planted some ornamental onions (Alliums) in their garden, you may think, "Onions?" It is true that onions are part of the Allium genus, but there are a handful of striking ornamental varieties that have earned their way into gardens across the country. Alliums are unique garden plants that are perfect for perennial borders, accent plants and even containers. Not only are ornamental onions eye-catching, they are all virtually deer proof and drought proof. People won't believe that the plant they are admiring is the edible onion's close relative.

Most gardeners are familiar with the spring blooming ornamental Alliums that arise from bulbs planted in the autumn. Less familiar are the summer and fall-blooming species, many of which grow from rhizomes. Carroll Gardens carries several popular species of ornamental onions; this week we are featuring the Allium senescens and the Allium senescens Glaucum - incredibly low maintenance perennials that grew in grandmother’s garden.

Allium senescens - Easy to grow and durable
Nodding flower buds arise to umbels of 2" lavender flowers in midsummer. These are the focal point of the Allium senescens - unique globes of color will attract attention not only from anyone who walks through your garden, but also from several species of butterflies. The bright green, flat foliage that surrounds these gorgeous blooms forms a neat 1 foot tall mound creating a wonderful compliment when planted in front of yellow hemerocallis (daylilies). Excellent for edging or the border foreground; grows only 8-10 inches tall. In my opinion, the best of the ornamental Alliums. Quick to clump-up, easy and permanent, Allium senescens blooms beautifully even in the worst of droughts. A great alternative to Liriope.

Allium senescens Glaucum - Curly Twist Allium
The Allium senescens Glaucum is very similar to the Allium senescens with one distinct feature. It has blue-grey foliage that is twisted, providing a beautiful background for the lilac flowers that bloom in July. All of the leaves twist in the same direction. With age, the center opens up like a wreath. Although the flowers are beautiful, it is the unique foliage that will enliven your garden throughout the growing season.

Planting and Care

Plant in Zones 4 through 8.
Prefers full sun; tolerates very light shade.
Plant 18 inches apart in any well-drained soil.
Water regularly until established.
Easy to grow and extremely drought tolerant once established. As durable and
carefree as a perennial can be.
Very deer resistant.
Fertilize with Flower-tone in early spring and late autumn.
From two quart pots.

Our Garden Worthy Certification means that your satisfaction is guaranteed.

Allium senescens

Allium senescens Glaucum

Garden Club Questions and Answers

Question: I am hearing conflicting advice on how far to cut back the old blooms on my Endless Summer Hydrangea. If I cut it back farther will I have more blooms? Or should I just remove the old blooms and leave as much stem as possible?

Answer: I usually remove just the faded flower to get the quickest rebloom. If you cut back further you will probably get more branching and thus more flowers. But they will probably be smaller and bloom a week or two later than if you had removed just the old flower.

Question: I have a crape myrtle that has refused to bloom for the past two years. Do you have any idea what the trouble could be?

Answer: I can think of several possibilities. Individual varieties of crape myrtle vary as to when they start blooming. You may have one of the later ones, which would explain this year at least. Crape myrtles bloom best in full, hot, blazing sun from early morning until late evening. In the shade, crape myrtles bloom later, or not at all. Finally, crape myrtles that were frost damaged or cut back in the spring often bloom later.

Question: I planted Larkspur seeds this spring but most of them did not come up, and none of them bloomed. Do you have any idea what I did wrong?

Answer: Larkspurs are one of the most satisfactory annuals to grow from seed. Sow the seeds thinly exactly where you want them to bloom; don’t plan on transplanting the seedlings. Larkspur needs cool soil to germinate. In most of the country, you can sow the seeds in the fall. The plants will survive the winter and bloom the following spring.

Larkspur seeds can also be sown in late winter. If sown at this time, they will bloom the same year in late spring. Incidentally, have you tried the double flowered larkspur that grows only about 18 inches tall?

You may have trouble finding seeds in the fall. Most seeds that you see in picture packs in the stores do not actually belong to the stores. They are consigned by the packager and the store only pays for what is sold. The packager counts up what has been sold at the end of spring and then removes the display from the store. Your best bet is to try an independent garden center. Some of them make special arrangements to keep their seed racks into the autumn.