Are you sure it was a shrub? Looks like an Iris seed pod. Was the colour originally more orange than in the picture? If so may be Iris foetidissima aka Stinking Gladwyn. Also possibly from a Bearded Iris, although personally I've never seen a ripe pod. I don't think it's Iris pseudacorus aka yellow Flag, because that has brown seeds.

To be honest I'm not too sure I'm afraid!
With one thing and another I had forgotten about it and just found it recently and the seed pod had cracked open so hadnt previously seen the seeds.
I'll plant it and see what happens!