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Herbs, Flowers & Specialty CropsGladiolus Planting Calendar
Gladiolus corms are planted in spring and again in a series for a long cutting season. The rules are simple: stagger plantings, plant at the right depth and lift the corms before hard freeze.
Key points
- Plant glads from about a month before the last frost, then every two weeks, as one Missouri guide describes.
- Expect bloom 70 to 90 days or more after planting.
- Plant by corm size and draw soil up around stems.
- Lift four to six weeks after bloom and cure corms before storage.
When can you plant gladiolus corms?
University of Missouri Extension says glads can be planted as early as a month before the average last frost date, then every two weeks for continuous bloom, and that the final planting should be made by early July so corms can mature before frost.
Those figures come from a Missouri guide, so use them as a method and adjust to your own climate. Find your average last frost from the National Weather Service or your county extension office.
A soil thermometer and a weather watch help with the earliest plantings, since a hard freeze can damage young shoots. Cover or replant if a hard freeze hits.
- Check the average last frost.
- Plant the first batch a month ahead of it if soil allows.
- Add a new batch every two weeks.
- Stop by early July in a Missouri-like climate, or count back from your own first frost.
How long until glads bloom?
The same source reports that bloom typically arrives 70 to 90 or more days after planting, depending on weather and variety. Use that range and the days listed for your variety to count backward from your first fall frost to find your last planting date.
Cool weather slows development, so add a margin if your season is short.
If you want a steady supply, record each planting date and the date of first bloom. Next year, use your own numbers instead of the general range.
- Count back from first fall frost.
- Add a margin for cool weather.
- Record the first bloom date.
- Adjust planting intervals next year.
How deep and how far apart should you plant them?
Depth depends on corm size. Missouri Extension recommends 4 to 6 inches for large corms, 3 to 4 inches for medium corms and 2 to 3 inches for small ones, initially covering with about 2 inches of soil and drawing soil up around plants during cultivation.
Space corms according to the package or plant in rows if you are growing for cut flowers. Deeper planting helps support tall stems.
- Set corms pointed side up.
- Cover with a couple of inches at first.
- Draw soil up around stems as they grow.
- Water after planting.
What soil and site do glads need?
Full sun and well-drained soil are best. Tall spikes need shelter from wind or support, such as netting or stakes. A soil test and local recommendations guide any fertilizer, and nutrient management rules vary by state.
Rotate planting sites from year to year to reduce disease problems. Keep weeds down while plants are small.
Corms store energy, so leave at least a few leaves on the plant when cutting. Cutting too deeply weakens next year's corm.
When should you cut glads?
Cut spikes when the lowest few flowers show color, and keep stems cool. Leave at least a few leaves on the plant, since the corm needs foliage to grow for next year.
Bring cut stems into water at once, and recut stems before arranging.
Stake or net rows before spikes get tall. Wind can snap stems and ruin a planting in one afternoon.
How do you lift and store glad corms?
Missouri Extension advises digging corms four to six weeks after flowering ends or when tops die back, and before a hard freeze. Wash off soil, trim tops to about half an inch above the corm, and cure corms in a dry, airy spot for two to three weeks. Then remove the old corm and sort corms and cormels by size.
Store cured corms in a cool, dry, ventilated place. In mild regions corms may overwinter in the ground, so ask your extension office what works locally.
- Dig before a hard freeze.
- Cure in a dry, airy spot.
- Sort corms and cormels by size.
- Discard soft or damaged corms.
What problems should you watch for?
Thrips, leaf diseases and corm rots affect glads. Rotation, clean planting stock and careful curing reduce losses. Ask your extension office to identify issues before treating.
If you consider a pesticide, the label is the law, pre-harvest intervals apply and applicator licensing varies by state. Glads attract pollinators, so protect them.
- Rotate planting sites.
- Use clean corms.
- Cure corms carefully.
- Ask extension to identify problems.
Timing at a glance
| Item | Window | Caveat |
|---|---|---|
| Gladiolus planting in Missouri, University of Missouri Extension | As early as a month before the average last frost, then every two weeks; last planting by early July | Source guidance for Missouri; use your own frost dates and days to bloom. |
| Gladiolus bloom time, University of Missouri Extension | About 70 to 90 or more days after planting | Varies with weather and variety. |
Sources and further reading
Last reviewed: November 2026. Educational information, ranges only. Confirm timing with your county extension office.