If you left any roots they would indeed send up a new shoot. Also costus will root from stem cuttings I'm told so any broken pieces of stem that got buried may have rooted. I have costus also but have never tried the stem rooting before so I'm unsure if that last is fact or fiction ;o)
Mike

costus speciosus is one of the few that gets pollinated easily, and makes tons of seeds. birds tend to spread them all over the place, so yes its quite possible they are seedlings. often you'll see a mat of seedlings though, if a whole pod falls and gets covered up the season before. One cone can produce hundreds of seeds, so its pretty productive.

Tim Chapman

Every spring I have to weed out tons of the seedlings, but a few always escape into hidden corners. They grow pretty fast, so if you don't want to be overtaken, get them out early.

Thanks all. Looks like seedlings as there are about 20+ or so 2 inch high babies as a "mat" about 2 inches to 2 feet away. Must have been a seed pod falling and then covered up as Tim suggested. I just never had this happen before so now I know:)
cajunmama

If they become a problem, its easy enough to cut the inflor.s off before the seed drop... they make decent cut flowers as well. I prefer to just let them drop and collect seedlings as needed for potting up. I do wish some of my other costus would seed as well, but most (here at least) require hand pollination.

Tim Chapman

Tim
I do plan on potting them up to share with friends. I let the inflorescences stay on these as the area was taken over by vicious wasps last summer and after a couple of stings I just enjoyed them from afar...I like free plants so don't think they will become a nuisance. Thanks again for the information.
Cindy

Do you ever get any seeds off the variegated form, Tim? That is the only speciosus we've got (although lately some stems are reverting to green), and I've never noticed any seed set on them. If so, I think you know what the next question is going to be...

the variegated one never blooms here. further south (ie in florida) it will. I've never greenhoused one to bloom it though. I should try it. I'm pretty sure the answer to your next question is probably no, but unproved to my knowlege. I've only seen the in bloom, never at seed setting maturity, if i had i'd have some seeds to try.

Tim C.