Elephant garlic is an odd little plant. Although it looks like a giant garlic bulb and has a mild garlic flavor, it is more closely related to leeks than to garlic and has a tendency to alternate each year between forming one large bulb or "round" and forming many small cloves.
Elephant garlic is a biennial and you get the single bulb in the years that the plants don't flower. All of the plant's resources go into building up the single bulb that will help the plant survive into its second year and send up flower stalks. If you re-plant the large bulb, you should get a plant that sends up a flower stalk and develops smaller cloves. When the cloves get large enough, they will repeat this cycle.
Allium ampeloprasum var. ampeloprasum
Elephant garlic is a biennial, so each plant will only live for two years. However, the plants should be reliably hardy in USDA Zones 3-9.
Although the plants will grow and bulb in partial shade, you will get larger bulbs if you grow your elephant garlic in full sun.
Mature Plant Size
Elephant garlic will reach a height of about three feet. It has the typical leaves of allium plants and will spread up to 10 inches.
Days to Harvest
As with true garlic, elephant garlic is usually planted in the fall and harvested about eight months later, in the following summer. Fall planted garlic may have enough time to split into cloves. If you find they're still one large bulb, you can leave them in the ground for another year, to finish maturing.
Spring planted elephant garlic will be ready to harvest in 90 days, however, it will most probably be a single large bulb.
Harvest when the majority of the leaves have started to turn brown or yellow. Test by digging up one or two bulbs and checking their size.
Elephant garlic prefers a neutral soil pH of around 6.0 - 7.0. Good drainage is more important than soil pH. Do not plant your elephant garlic in soil that stays damp or the bulbs will rot. Amending the soil with compost or some other organic matter before planting will help the soil retain enough moisture, without becoming water-logged.
Elephant Garlic Planting Tips
Divide the bulb into individual cloves, for planting. Plant each clove 4 - 6 inches deep. Space them about 8 - 12 inches apart, to allow some air flow between plants.
Give your elephant garlic plants regular water, at least 1 inch per week.
Elephant garlic will send up flower stalks, or scapes, just like regular garlic. The scapes are drawing energy that should be going toward bulking up the bulb. Cut the scapes before they begin to curl or bloom. The scapes are edible and make a lovely pesto.
Harvesting and Storing
Harvest when the leaves start to yellow and turn brown. Once harvested, allow your elephant garlic bulbs to dry for a few days, in a cool, shady spot. When dry, brush off as much soil as you can, but do not wash the bulbs.
If you plan on storing elephant garlic, it will need to be cured. Let the bulbs sit in a cool, dark spot for 3 - 8 weeks. Make sure there is good air circulation. Use a fan, if you have too.
After curing, you can cut off all but about an inch of the flower stalks and any remaining roots. The skin may be papery at this point, but let it remain on the bulbs.
Store the elephant garlic bulbs where they will remain at about 45 - 55 degrees F. and no more than 50% humidity. With these conditions, your elephant garlic can keep for 8 - 10 months. In less ideal conditions, use your bulbs within 3 - 4 months.
Pest and Diseases of Elephant Garlic
Elephant garlic is relatively problem free. Slugs can be an issue, during damp seasons. There are a few fungal leaf diseases that can affect the plants, but buying certified disease-free bulbs and providing the plants with room for air flow should limit the problem.
Best Varieties of Elephant Garlic to Grow
There are no cultivars of elephant garlic. You may see it offered as hardneck or softneck, but both types will produce similar bulbs. The hardneck will also produce garlic scapes which are wonderful additions to pesto and other dishes.