Gladiolas winter well in a pit, but...

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Gladiolus byzantinus, a.k.a. Gladiolus communis ssp. byzantinus. 

...some species are hardy!

Store them cool but not freezing over winter, or choose hardy species.

I heard you talk and wrote a summary for to share a few tips that stood out for me in your talk.

One of the tips was about burying cannas and dahlias 18" to keep them over winter-- this is such an awesome tip because I have nice soil in my veggie bed doing NOTHING over winter, when it could be storing these semi-hardy tubers/bulbs!

I know you said elephant ears would have to go down deeper to at least 24", but what about glads? Could they be OK at 18"? - Monica Milla -


Thanks for letting people know about us, Monica!

This winter, if this warmth continues, cannas may make it through to spring without any protection at all in our portion of "zone 5." Gladiolas are not quite so tough (most Gladiolus species are zone 9) yet we've seen them pull through a few special winters in special places, too.

Could the glads make it through a normal zone 5 winter (down to -20°F) if buried 18" deep? Probably. However, we've only ever put Gladiolus bulbs into deeper pits -- we had a pit dug for other things and so stashed all our special things there. We haven't tried them in shallower storage. However, we think they would survive with 18" of Mother Earth as insulation.

There's more about burying tender perennial roots as a winter storage method in Ensemble Weekly Editions

What's Coming Up #7 and

What's Coming Up #160

Hardy glads hardly the same as their big cousins

Most of the 180 species of Gladiolus, including all of those used to develop the very popular cut flower hybrids, are native to frost free parts of Africa (especially South Africa), Arabia and Madagascar. That's zone 9 and 10. A few that come from Europe and the Mediterranean can tolerate some cold if the drainage is very good.

Zone 6 species: G. byzantinus (also known as G. communis ssp. byzantinus)*,G. illyricus, G. imbricatus, G. italicus.

Zone 7: G. tristis, G. atroviolaceus

Zone 8: G. papilio, G. cruentus, G. x colvillei, G. saundersii


Gladiolus byzantinus have been resident in our well-drained zone 5 gardens for 20 years. Above, it is in bloom with catmint (Nepeta x mussinnii) and swamp buttercup (Ranunculus acris) in spring. They're interesting but not the show-stoppers their big hybrid cousins are. In addition, G. byzantinus multiplies like grass and have to be thinned every year or they plants quickly become too crowded to bloom well.