They're considered an annual here, but will sometimes return in a protected spot.

In my zone 5b/6a, they must be dug and stored for replanting the next year...just like dahlias and canna.

The glads are quite a lot easier to dig and store though.

Sue

Hello there, I live in Huntington WV. I planted many glads along a garage and they come up every year without digging them up. I did this about 10 years ago and I still see them when I drive by in the spring.
I was about 19/20 years old then and just planted things willy nilly. :)

I've had two good seasons from winter-hardy gladiolus in central Ohio. Shorter than traditional glads (mine are about 20" in part-sun, but very pretty. Mine have an interesting assortment of pink, red, white and patterned; my favorite are a bright warm red, with yellow throats.

Just wish they were longer lasting!

(The glamour foto; not from my garden.)
{{gwi:1070608}}

I've had glads that have lived for several years and not been dug in the fall. I try to plant them a little deeper, like about 6-8 inches deep. That seems to help them stand up straighter when blooming too. We had an extended cold snap this year. Will they come back? Time will tell.

Janet