I guess if my gladiolus bulbs that I don't pull out every fall, keeps growing in the following spring (as well as evidence of new plants naturalizing in that area), counts as similar to planting in the fall, then I've done that.

I'm in Zone 8 and have mild winters. I can also leave dahlia tubers in the ground outside and they return every year, getting bigger and bigger until the time to divide them.

I have also done it where I left them in pots, which make them experience conditions different from the ground, and they still survive.

Matt, are you in a cold winter zone?

Here in subtropical land I planted some late, maybe July. They have not bloomed for 2 years in a row since then.

im in zone 7- I know for a fact that all my gladiolus thrive in my location

Nice!

I am in zone 7a. They survive fine here, but I have always planted in Spring where they are locally available

I saw this on some website saying that you can plant Gladioli from August to December?

I don't have any really expensive gladioli. I either buy them from online when they are on sale or buy packages from big box stores. The only thing I have found is in my zone (8b), it usually gets too hot and dry in August to plant them. However, this is interesting that the site you found says plant all the way to December.

Well I'm wondering if I can trust their judgement, on when to plant my Gladioli.

Was that site in Australia?

Glads thrive here but the ones I planted late (July) have yet to bloom after 2 years. Healthy foliage tho.

I tried to find that information and I think maybe it came from New Zealand?

oh, well that explains it