How bad is it? It's ludicrous and poorly paced.
Should you see it? yes, if only for the cast.
An expedition finds a tropical island in the Antarctic, where there are mobile, acid-spewing, intelligent plants. It's up to Mamie Van Doren, Bill Gray (of Father Knows Best fame) and song and dance man Bobby Van to save the world! Most of the male cast seems more interested in Mamie than the monsters, but she isn't shown to her best advantage (though there are a lot of profile shots...) and the movie seems to run out of steam; walking plants just aren't that terrifying.