Growing Gladiolus Flowers

gladiolus flower

Last week I was walking through our local garden store when I noticed a beautiful bag of gladiolus bulbs. I actually didn’t buy them at the time because the gladiolas is an annual and I thought it would be a lot of work to dig up 70 bulbs at the end of the season!

But, I did a little bit more research, to find out if these flowers would perhaps come back without needing to replant. Sure enough, I found a few instances of people living in colder climate zones such as ours {We are zone 6b} – and their gladiolus came back for several following years.

So, while I’m not sure if they will indeed come back next year if I don’t dig up the bulbs this fall, I decided it was a risk I was willing to take. They are such beautiful flowers, so while I was at the store again yesterday, I did decide to pick up a bag, and now I’m ready to plant them!

Gladiolas are not true bulbs like one might think. They are actually what is known as corms. While they look like bulbs on the outside, they actually are quite different on the inside! They are more of a root with a store of seed and nutrients than an actual bulb.

The advantage to corms of course is you only need to buy them once – but there is a bit of labor involved each spring and fall if you are in a northern climate, so that is something to consider.

The plant is only hardy technically in USDA garden zones 8-12. We are in garden zone 6b, so I am not sure if they will survive the winter, though I have heard a few people successfully doing it.

It was because of this I was not so sure I would want to go through the hassle of having them in my garden. Unlike most flower bulbs which would come up every year with little maintenance, corms typically need to be dug up at the end of the fall for each year and then replanted again in the spring.

I did decide to grow these in my garden this year anyways. I am planning to plant them deep into the ground – about 8″ deep and then mulch them heavily in the fall so that they may be protected over the winter.

They may or may not come back – here’s hoping that they will!

These flowers are very pretty and often used in cut flower arrangements. They are a fantastic choice to use for fresh-cut flowers. You can cut them and put them in a pretty vase easily.

gladiola bulbs

Something I’ve learned is that if you want fresh cut flowers all summer long, you will want to plant new corms each week from the last week of May through the second week of July. The plants take about 8 weeks before they are ready to bloom, so if you do this, you will have flowers all the way through September before the frost hits.

These plants only bloom once per season, so this is a large part of why spacing out the time you plant them is popular.

Of course, you can plant whenever you want – just keep in mind they will take about 8 weeks to grow. You should also plant them when the ground is warm. They will not do well when it is very cold outside. For us, this means the end of May after all risk of frost is gone is a good time to plant them.

Safety Warning: Keep Away From the Cat!

sleepy cat
Our cat taking a nice nap after a long day of gardening. He doesn’t eat the plants as much as his sister does!

One thing I did not know is that gladiolas are toxic to cats. Most of our cats do not eat the plants outside, so I do not think this will be a problem while the flowers are in the ground. 

My bigger concern would be if I were to cut them and bring them inside the house. We’ve found our cats eating our plants indoors in the wintertime more than we’d like to admit!

Gladiolas are a member of the iris family. The iris family is toxic to most cats, so this is something important to consider if you think your cat might get into the plant and try to eat it.

If you have cats, it’s always important to check these things and take them into consideration when choosing plants. It’s best if you can teach cats to not eat plants while they are young kittens. Of course, we all know it can be tough to train a cat!


Growing Gladiolus

growing gladiolus

The first step to consider is where you will plant these flowers. They need a bright, sunny spot that gets sun most of the day.

The bag that I bought had 70 corms. That’s a LOT of flowers! I figured though it wouldn’t hurt to have that many, and I could always plant a few extra in different areas as well.

In researching how to prepare my garden bed for these beautiful flowers, I learned that they need well-drained soil, as most plants do! They will grow in sandy soil also.

I used my own DIY potting mix of topsoil, sand, and a little bit of compost. Our dirt here is the worse kind of clay dirt you can imagine, so it needs a little TLC for most things.

The recommended spacing for these when planting is about 6″ apart. It is common to put them in rows, so many people will dig a row that is about 6-8 feet long and 8 inches deep.

When you plant them, it is a good idea to go at least 8″ deep into the ground. Some will recommend that you go even deeper – up to 12″.

This is because the plants do get a bit tall and the wind will blow them around a lot if you are not careful. Some people will stake them when they are growing them specifically for the fresh-cut flower aspect to ensure no damage comes to the blooms.

Overwintering Gladiolus Bulbs

When the season is over, it is important that you take the right steps if you want to enjoy gladiolus bulbs and blooms the next summer!

After the plant has flowered, and the first frost is nearing, you will notice the plant starts to wilt. When the leaves start to turn colors and you are certain it is done, you can dig up the corms.

The corms can be prone to a couple of issues during the winter months, especially when stored in damper spaces like a shed or basement. It’s important that the corms do not develop any sort of fungus on them. There are many products

Using a product like Physon-20 is recommended before storage and after storage. This is an EPA-approved product that can be used to protect the plant from disease and pests. It is useful to have in the garden for all sorts of plants!


I hope you enjoy the Gladiolus flowers and of course I will update this post when I get the chance to share if they did indeed survive the winter!

Have you ever grown Gladiolus? What do you like about this plant? Have you had any luck in keeping them in the ground over the winter? I’d love to hear from you in the comments section below!

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