Here’s a question from a reader:
Is it necessary or advised to cut gladiolus down before winter?
Thank you. I enjoy reading your tips.
Town of Tonawanda
I was surprised by this question. It never occurred to me that you might cut off the foliage; I thought you were supposed to bring in your gladiolus bulbs for the winter.
Since I’m not a gardening expert, I asked my friend David Clark, who is a nationally known garden educator, to weigh in on this. (He teaches the entertaining and informative horticulture classes at the Buffalo and Erie County Botanical Gardens. You don’t have to sign up for the series; you can take single classes.)
First of all, don’t cut off the green leaves, Clark said.
The plant is translocating or moving nutrients into the root structure. Wait until the leaves turn brown and get crispy.
If you have the proper microclimate, such as next to the foundation of your house, you may be able to leave the plants in the ground over the winter and they may come up again next year, he said.
Clark emphasized may come back; it depends on your microclimate. Wacker says her glads are up against the house. She has never dug them up and they come back, so we know it’s possible.
If you leave them in the ground, you can cut off the foliage after it turns yellow or brown and get crisp, he said. Cut the leaves about one inch above the top of the corm. (Although most of us refer to them as bulbs, a gladiolus actually has a corm, Clark pointed out. See the differences between corms and bulbs here.)
If you don’t have a sheltered spot, you should bring your gladiolus corms in for the winter, Clark said.
Keep the gladiolus corms outside until there’s a frost and the leaves turn yellow or brown and get crisp. Dig the corm out of the ground and dry it. This is an important step because if it’s wet, it could rot while it’s in storage. Set the corm on a screen to dry in the sun, or if it’s rainy out, you can dry the corms in a garage, basement or attic. However, don’t let them freeze.
When they’re dry, you can cut off the foliage, leaving about an inch of leaves.
You want to coat them with a fungicide, but Clark says novices shouldn’t work with commercial fungicides because of the precautions you have to take. Instead, get some powdered garden sulfur or use plain old cinnamon powder– the kind you bake with.
Put the powder in a paper bag and add a corm. Shake it up so the corm gets coated.
Store the corm in a different paper bag with the top rolled down. Or use a box with the top cut off, filled with sawdust.
Label your corms. This is especially important if you have different colors or different varieties.
“You won’t remember what it is in the springtime,” Clark said.
Place the box or bags in an area that is dark and cool, about 50 degrees Fahrenheit. Attics and basements are good. You could keep them in a unheated garage that is attached to the house if you keep them in the area closest to the house. If you keep them in an unattached garage that isn’t heated, the corms will freeze.
Check them every so often from November to March and remove any corms that are mushy or rotting.
“One bad apple spoils the entire lot,” Clark said, and that can happen to your gladiolus corms, too.
Bonus tip: To get a jump on the season, plant your gladiolus corms inside around March 15, Clark said. Water them and make sure they have really good light. Then transplant them outside. You’ll have a four-week jump on the season.
You can invite David Clark to speak to your group. Find out more here.
How to get your questions answered
Sometimes readers contact me with questions that I can’t answer. I’m not a gardening expert– I’m a writer by profession. I interview knowledgeable people in order to provide you with great articles on Buffalo-NiagaraGardening.com.
So when someone asks a question I can’t answer, I often post the question and rely on my readers to share their expertise.
Sending a question to me to post can be helpful if you’re looking for a wide range of opinions and don’t mind waiting for the answer. If you want to try this route, email the question to me at firstname.lastname@example.org and I’ll pose it to my readers in an upcoming issue.
A more efficient route for getting your questions answered is to turn to Master Gardeners with Cornell Cooperative Extension or to turn to your local garden center.
For Master Gardeners at Cornell Cooperative Extension Erie County, call (716) 652-5400 from 9 a.m. to noon weekdays or email them at email@example.com. For Chautauqua County, email your question to CCEMGCC@gmail.com; call the Helpline at (716) 664-9502, ext 224, or stop in to the Frank Bragg Ag Center, 3542 Turner Rd., Jamestown, from 1 to 3 p.m. Wednesdays.
There are helpful Cornell Cooperative Extension offices in other counties, too. Find contact information here for your county’s Cooperative Extension office.
The businesses that support this magazine have very knowledgeable staff. Check out our Gardening Directory or click on the ads to the right.