Perhaps the earliest botanical horror?

Plant-based horror has always been of interest to me (perhaps because growing up, the Goosebumps book and two-part episode Stay Out of the Basement were favorites of mine), and botanical-related horror films have always fascinated me to (such as The Ruins, The Revenge of Doctor X, The Mutations/The Freakmaker, The Little Shop of Horrors, and one of the segments in Twice-Told Tales).

To be fair, the plants in this movie aren't the antagonistic force - that's Gale Sondergaard's character. But there is a scene in which some plants are being fed blood, and they seem somewhat able to move (one wraps a vine around Sondergaard's arm), so while not exactly in the same vein as something like The Revenge of Doctor X, I think it qualifies.

It's a short movie, just under an hour, but I certainly found it decent. The print I saw was scratchy, but if you're into classic horror, this might be worth a look.