Have been trying to get a patch going at woods' edge in zone 6 for a while,
without success.

First try: ordered plants in spring, got plants with leaves, planted a
couple of months before they went dormant. The leaves fell off, and nothing
ever happened except that around September the squirrels dug up the corms
and chewed on them.

Second try: ordered corms in August, but they didn't arrive till
mid-October. Looked like they were ready to get going, but was it too late?
Planted them, nothing happened in the fall. This morning I noticed one of
them sitting on top of the soil with some gnawing marks - evidently dug up
and tasted, then abandoned.

Any clues on getting these things to grow, before they get dug up and
destroyed? Conditions were pretty normal: not too much water, but not too
dry, either.