Gladiolus in Zone 5a & 5b
Gladiolus spp.
When to plant gladiolus in zone 5b
Zones 5a and 5b share the same average frost dates in our data, so this page covers both.
Method: Direct sow: Direct-sow outside. Gladiolus doesn't transplant well, or doesn't need the extra time indoors.
| Start indoors | Not typically started indoors |
|---|---|
| Direct sow / transplant outside | Apr 26–May 3 |
| Estimated bloom | Jul 25–Aug 1 (~90 days after direct-sowing) |
Spacing: 2 per square foot (square-foot-gardening spacing). Mature height: 2-4 ft.
Gladiolus is the one bulb crop in this group that runs on the opposite calendar from tulips, daffodils, and the rest. It's planted in spring, not fall, and blooms the same summer instead of waiting through winter, sending up 2- to 4-foot spikes lined with ruffled, trumpet-shaped flowers in almost any color you can order.
How gladiolus fits zone 5's season
Zone 5b's frost-free window runs about 148 days, from May 10 to October 5. Gladiolus needs about 90 days from sowing to first harvest.
Good companions
No standout companions recorded yet for Gladiolus.
Where to buy gladiolus bulbs
We haven't vetted bulb/tuber suppliers yet. Our seed-supplier list below doesn't carry these. The growing-guide source cited above is a good starting point for where to buy.
See it growing
Search YouTube for "growing gladiolus" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
← Back to the full zone 5b calendar · Full companion planting guide · Full plant profile · Plan your beds in the Garden Designer →
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Growing Gladiolus in USDA zone 5b: when to start seeds indoors, when to direct-sow, and when to expect a bloom.
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