Q.Pony Tail pups
In early May, I removed a number of new pups from around the middle of the plant – not the base. I’ve kept them in a large plastic bag and keep misting them, but there has been no root development. How long does this take?

Certified GKH Gardening Expert
Often they are removed from the base and already have roots. I would go ahead and pot them up and see if they root that way. Keep the soil moist but not wet.
https://www.gardeningknowhow.com/houseplants/ponytail-palm/propagating-ponytail-palm-pups.htm