When to Plant Gladiolus
Ask Julie Answers, Flowers, Lawn and Garden by Julie Day
“When is the best time to plant gladiolus? And should I order them online or buy locally?” -Beverly
Gladioli (Gladiolus sp.) bloom in midsummer. Technically a corm, not a bulb, they are considered tender, which means they do not require a period of cold in order to bloom (unlike bulbs like daffodils, which must be chilled in order to bloom). They can be planted in the spring around your last frost date, and take 60-100 days to bloom. Do successive plantings two weeks apart until June for a nonstop late-summer show!
As for where to buy them, it’s up to you, but your local garden center may have only a limited selection, particularly if they only sell packaged bulb mixes. Ordering will give you access to the hundreds of unique varieties of gladiolus, but shipping delays may put you late in the planting season.
Either way, make sure your gladiolus corms are plump, healthy, and primed to bloom. Gladiolus corms are given a number rating based on their size (#1 is large, #6 is small). Buy no smaller than #3 corms in order to have blooms this year. Or, if you don’t have graded corms to choose from, pick corms larger than 1” in diameter.
Most varieties of gladiolus are hardy to zone 7 and can be left in the ground over the winter. In areas colder than zone 7, they will need to be lifted in the fall and stored with your other tender bulbs.
Further Information
- Understanding the Types of Bulbs in Your Garden
- Hardy vs. Tender Bulbs
- How to Store Tender Bulbs Over the Winter
