It's hard because I wrap the stem in wet paper towel and then wrap that with tin foil. So time consuming. The woman I raise with taught me a lot of tips and one is to take a used, cleaned out cat food can, cut florist foam with it, put the foam in the campn, dampen it and put the milkweed stalks in the damp foam. She says swamp milkweed will keep for days doing this but I have had no success growing swamp....only common. I have to change common daily. It does dry out so fast.
Yes, all my cats are indoor raised in glass aquariums with a screen top. My aquariums don't facilitate a long stem but that sounds so much easier.