5 Spring Bulbs You Should Dig Up Now
With winter on the horizon, fall is the best time to dig bulbs that are susceptible to cold damage. Join farmer Briana Yablonski to learn about five bulbs, tubers, corms, and rhizomes you should dig up now.
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When you think of flower bulbs and crisp autumn air, you may imagine grabbing your spade and tucking bulbs into freshly dug soil. And that makes sense since fall is the best time to plant spring bulbs like daffodils, tulips, and hyacinths. However, fall is also the best time to dig up corms, tubers, and rhizomes that are sensitive to the winter cold, especially in areas outside their hardiness range.
Although not all of the plants on this list grow from true bulbs, they emerge from some type of underground storage tissue. In colder regions, digging these cold-sensitive plants in the fall and storing them indoors allows you to enjoy the plants year after year without purchasing more planting material.
Since the main goal of digging up bulbs now is to protect them from cold, not all growers need to lift them from the ground. If you live in a warm climate, you can likely leave the plants in the ground year-round! If you’re not sure whether or not you should dig, take a look at the details for each plant.
Dahlias
Dahlias grow from underground tubers that resemble small, tan sweet potatoes. Once the tubers receive the proper moisture and temperature, they form sprouts that force their way above ground. The plants then spend a few months growing before they produce the beautiful flowers we love. Whether you’re partial to large dinner plate blooms or compact pompon flowers, you can find a dahlia that suits your tastes.
Most growers plant dahlias in the late spring or early summer to enjoy a harvest that lasts from the late summer into the fall. However, you can also pre-spxrout dahlia tubers indoors during the winter and transplant the resulting shoots in the spring. This method works best if you have a structure like a high tunnel to protect the tender species from the cold.
Since dahlias are cold hardy in zones 8-12, you can leave them in the ground if you live in a warm area. Covering the tubers with a few inches of mulch will provide added insulation and help the tubers survive any cold spells.
If you live in growing zone seven and below, the tubers will unlikely survive the winter outdoors. While you can purchase and plant new tubers each spring, you can also dig them in the fall, store them over winter, and replant them the following year. And since the tubers multiply as they grow, you’ll end up with more than you planted!
When and How to Dig
Although you can dig dahlia tubers any time before frost, most growers wait until after the first frost has arrived. The frost will kill above-ground foliage, but the tubers will remain unharmed. It’s important to remember that different varieties produce similar-looking tubers. Therefore, you should label them while they are still flowering.
Since dahlia tubers expand as they grow, be careful not to stab them. Use a shovel or digging fork to dig up the soil a foot away from the stem. Remove any excess soil and gently wash the tubers in water to remove any remaining soil. After you dry the tubers, you can overwinter them in a cool location with moderate humidity.
Tuberous Begonias
Many gardeners love the colorful flowers and beautiful foliage of begonias. But did you know that there are multiple types of begonias? Some begonias grow from underground tubers, hence the name tuberous begonias.
This type of begonia thrives in shade and continues to bloom throughout the summer. Therefore, they are great options for the edges of forests and shady areas beside homes. You can find cultivars that produce various flower colors, including pink, red, yellow, and white.
Many garden centers and nurseries carry tuberous begonias during the spring, making it easy to add them to your garden. However, you can also purchase the tubers and grow them out. Digging the tubers in the fall also allows you to overwinter the plants so you can replant them the following spring.
When and How to Dig
Since the tubers are sensitive to cold, you need to dig them up in the fall if you want them to survive the winter. Unlike some begonias, tuberous begonias aren’t good candidates for houseplants and will enter a dormant period even if they’re ground indoors. Therefore, your best option is to dig up the tubers in the fall and store them until the following year.
You can dig the tubers when the foliage begins to fade or after a frost has killed the above-ground portion of the plant. It’s best to decrease watering in the late summer to encourage them to enter dormancy.
Cut the stem a few inches above the ground and carefully dig up the tuber. Place the tubers somewhere inside that’s out of direct sunlight. They should be dry within two to three weeks. After they’re dry, place them in a bag filled with peat moss or vermiculite and store them in an area between 40-50°F (4-10°C).
Gladiolus
Whether you’re looking for tall flowers for arrangements or gardens, gladioli are a great choice. They produce elongated flower spikes that become covered with large, trumpet-shaped blooms. You can find flowers in colors including white, pink, red, yellow, and purple.
Gladioli grow from swollen stems called corms. Although the cold hardiness varies between varieties, most gladiolus corms can overwinter outdoors in zones 7-10. If you live in zone 6 and below, you should dig up the corms if you want them to survive the winter.
When and How to Dig
The best time to dig gladiolus corms is after they have finished flowering but before the ground has frozen. It’s okay to wait until the first killing frost arrives, but you shouldn’t wait more than a week after this moment.
Cut back any remaining foliage a few inches about the corm. Dig the corms using a shovel or digging fork while being careful not to pierce them. Once the corms are out of the ground, shake off any excess soil, but don’t wash them.
If you want the corms to keep well throughout the winter, you need to cure them before placing them into storage. Place them in a dry, warm (60-70°F or 16-21°C) area with excellent ventilation, and allow them to dry for three weeks. Once they are properly cured, store them somewhere cool and dry.
Canna Lilies
Canna lilies’ large green leaves and colorful flowers make them popular additions to gardens. While many gardeners love the tropical look they add to landscapes, this same tropical appearance is what makes them susceptible to cold damage.
This species can’t tolerate temperatures below 0°F (-18°C). However, you can successfully overwinter them in cold areas by digging up the rhizomes and storing them indoors during the winter. When warm weather returns, you can plant the rhizomes outdoors and watch the plants liven your landscape.
When and How to Dig
The best time to dig canna lilies is just before or after your first fall frost. Start by trimming any remaining foliage so just a few inches of above-ground stem remains. Next, use a shovel or digging fork to carefully unearth the rhizomes. Gardeners often bury canna lilies four to six inches underground, so make sure to dig deep enough under the soil surface.
After the rhizomes are out of the ground, brush off any excess soil and gently wash them with a hose. Place the clean rhizomes in a warm location out of direct sunlight for a few days to cure. At this point, they’re ready for storage.
You can either wrap the rhizomes in paper or place them in an open container filled with peat moss or vermiculite. Regardless of which option you choose, place them somewhere dark and cool throughout the winter.
Elephant Ears
Although elephant ears don’t produce stunning flowers, their large, colorful, heart-shaped leaves make them a popular addition to many gardens. However, if you want to grow these tropical beauties outdoors, you should be aware of their fragile nature. Most types of elephant ears can only survive the winter outdoors in zones 9-11.
One option is to grow them in pots that you move indoors during the winter. However, you may not have the space to store the plants indoors. Rather than letting them die from the winter cold, you can dig up the corms and store them indoors during the winter.
When and How to Dig
The best time to unearth elephant ear corms is when your first fall frost arrives. It’s okay to dig the corms a few weeks before the first killing frost, but you shouldn’t wait more than a few days after the frost.
Start by trimming any remaining foliage so it’s only a few inches long. Use a shovel or garden fork to dig a few inches away from the base of the plant, then lift the stem to unearth the corm. Brush off the soil and then gently wash the corms.
Place the corms in a warm, dry location out of direct light for about a week. When the outsides of the corms are dry, they’re ready for long-term storage. Wrap each corm in dry paper, then place them in a cardboard box or paper bag. Keep the corms somewhere dark and cool over the winter.