To add a delightful touch of whimsy to your garden this season, how about growing giant alliums? They’re a diverse group of ornamentals that seem to appear straight out of a Dr. Seuss book! And you’d never guess it from their looks, but giant alliums are members of the onion family (flowering onions).
In many sizes, shapes, and colors, giant alliums all share a subtle oniony scent when their foliage is crushed. The oniony smell shouldn’t deter you, though. The flowers are sweetly fragranced. And giant alliums are huge on charm, which makes them downright wonderful.
One super fun favorite is Allium giganteum. From its 4 foot tall stalks to its big 5-inch round purple clusters of flowers, Allium giganteum is sure to put a jumbo size smile on just about any face. A showstopper in early summer, plant Allium giganteum in your perennial garden for year after year enchantment. You won’t be able to resist the appeal of this gentle giant.
How to Grow and Care for Giant Alliums
Most giant alliums are hardy to U.S. Department of Agriculture Zone 4. They can be grown from seed, but growing them from bulbs is easier, speedier, and recommended. Look for bulbs in local nurseries for the varieties that will grow best in your region. Plant alliums in early spring or fall along with other bulb plants. Provide your bulbs with fertile soil infused with organic matter. With the exception of Allium giganteum, who can handle part shade, alliums like full sun.
Space bulbs of smaller plants about 4 inches apart and 4 inches deep. For larger varieties, space the bulbs 9 or 10 inches apart and 6 inches deep. Maintain moist but well drained soil conditions.
Alliums propagate themselves underground by forming bulblets. The bulblets will mature and flower within a couple of growing seasons. Some alliums seed heavily, too. Consider deadheading before your alliums self-seed everywhere.
Giant Alliums Pests, Diseases, and Problems
Members of the onion family have built in pest repellent with their potent flavor and smell. However, thrips and onion flies will occasionally try to give alliums a run for their money. To ward these pests off, keep your alliums and garden clear of weeds. Defend your plants with a strong spray of water if you spot these pests lurking around.
Alliums are susceptible to rot, mildew, and mold, too. These diseases spell out too much moisture for your plant. Prevent these problems with proper spacing between plants for plenty of air circulation. Make sure your alliums receive plenty of sunshine to dry them out. And that well-draining soil we mentioned earlier will help the bulbs stay moist but never soggy.
Other Allium Varieties to Try
‘Blue Globe’ onion (Allium caeruleum) is an ornamental onion grown for its striking true blue flowers. Beautiful alone in a garden, blue globe onions are brilliant as cut flowers, too.
‘Star of Persia’ (Allium albopilosum) is for the big, round, purple flower lovers out there. Its star-shaped flowers cluster up to a foot in diameter on shorter 2 foot stalks. Talk about fun!
Chinese chive (Allium tuberosum) is a late summer bloomer with fragrant white clustered flowers just in case you didn’t get enough giant alliums earlier in the season.