Gladiolus also known as gladiolas or glads are beautiful summer-blooming bulbs that add vibrant spikes of color to the garden. Their showy flowers come in bright hues like red, yellow, orange, pink, white and purple. However, gladiolus bulbs, properly called corms, are not cold hardy in areas with freezing winters. Knowing when to dig them up is key to proper gladiolus winter care and successfully getting them to bloom year after year.
Why Dig Up Gladiolus Corms
Gladiolus originated in warm climates like Africa, Asia and the Mediterranean They go dormant through the winter months and cannot withstand hard freezes or frost If the corms are left in the ground over winter where temperatures drop below freezing, they will rot and die. Digging them up after the foliage dies back in fall allows them to be stored indoors in a cool spot until spring. This keeps them dormant and protects them until the danger of frost has passed. Then they can be replanted for another season of beautiful blooms.
When is the Best Time to Dig Up Gladiolus
Proper timing when digging up gladiolus corms is crucial. It’s best to let the foliage die back naturally after the flowers finish blooming. The leaves need time to photosynthesize and transfer food reserves and nutrients back into the corms. This helps ensure large, healthy corms for the following year.
Here are some guidelines on the optimal time to dig up gladiolus bulbs:
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Wait at least 6-8 weeks after blooming ends – Allow adequate time for foliage to completely yellow and die back once flowers are spent.
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After the first hard frost – Dig corms soon after the foliage has been blackened or killed by temperatures below 28°F.
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When foliage is yellowed/brown – Corms can be dug once leaves have turned completely yellow or brown and died back.
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Before ground freezes – Dig before soil becomes frozen solid in late fall or early winter.
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October/November – The ideal months for digging gladiolus in most temperate zones are October and November.
Watch the weather forecasts. An early frost may mean you’ll need to dig earlier in autumn. It’s better to dig a little early before the ground freezes than too late after corms have already been damaged.
How to Dig and Store Gladiolus Corms
Follow these steps for proper gladiolus corm harvesting and winter storage:
Digging
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Use a garden fork or spade, inserting it 6-8 inches away from the corms to avoid spearing them.
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Gently lift plants from the ground and gently shake off excess soil. Don’t wash corms yet.
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Optional: Cut off faded flowers and dead foliage, leaving 1-2 inches of stem.
Curing
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Place freshly dug corms in a single layer on newspaper or screens. Allow to dry for 2-3 days in a warm, well-ventilated area around 70-80°F.
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Curing helps seal wounds and prevent rot diseases. Drying also stops growth and allows old corms and roots to detach from new ones.
Cleaning and Sorting
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Use a soft brush to clean off any remaining dried soil or debris.
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Carefully separate fresh, new corms from old ones. Discard any that are diseased or damaged.
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Keep large, healthy new corms for replanting. Set aside smaller cormels for growing on.
Storage
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Place cleaned corms in paper or mesh bags. Or pack neatly in trays or boxes with peat moss/vermiculite.
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Store in a cool, dark spot around 40-45°F. A basement, garage or refrigerator works well.
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Periodically check for moldy or rotting corms and remove them.
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Keep stored corms dry but not completely shriveled. Air out storage bags occasionally.
Following proper techniques for gladiolus winter care will reward you with healthy, thriving plants that bloom year after year. Just be sure to time your corm digging and storage correctly. With a little practice, you’ll become skilled at harvesting and storing gladiolus corms. The delight of their renewed flowers next season makes the effort well worth it!
Common Questions about Digging Up Gladiolus
How do you store gladiolus corms over the winter?
Keep the corms in a cool, dry spot just above freezing, around 40°F. Many people store them in the refrigerator vegetable drawer or unheated garage. A basement or enclosed porch also works well.
Can you leave gladiolus corms in the ground all winter?
In zones 8-10, gladiolus can be left in the ground and will often grow back the next year. However, in zones 3-7 they need to be dug up in fall and stored indoors over winter because they aren’t cold hardy enough to survive freezing temps.
What happens if you don’t dig up gladiolus corms?
If left in the ground over winter where it freezes, gladiolus corms usually rot and die. They generally can’t withstand temperatures below 28°F without being stored indoors in a protected spot. However, some gardeners have had success overwintering them in the ground in zones 5-7.
When should I dig up gladiolus corms?
In cold winter regions, dig up glads after the foliage dies back naturally in fall following the first hard frost. Be sure to dig them before a hard freeze below 28°F. Ideal months are typically October-November.
Conclusion
Knowing the right time to dig up gladiolus is important for their health and getting them to bloom again next year. Allow the foliage to die back completely before digging up corms in fall. Cure, clean and store the corms in a cool spot over winter. With proper timing and care, you can enjoy their vibrant flowers summer after summer.
