no, it is not too late. Plant gladiolus bulbs in the spring once danger of frost has passed and the soil has warmed. We have just crossed that bridge (at least where I live).

They should be okay.

Make plantings two weeks apart trough June for prolonged bloom. If you plant them all at the same time they all bloom at the same time. As it is you don't even get a good presentation for the entire time a individual corm is in bloom, due to the way the flowers open from the bottom of the spike up, with the first ones to open shriveling while the subsequent ones are still coming out.

Thank you! I'm relieved to hear I can still enjoy them this summer.