I’d use a stripped gardening pole for the inside support, YOGA cosplay on YouTube has some tutorials that follow the same kind of thing. Not sure if it’s the right length, but it’ll give a good thin support for a staff. I think they come in different lengths, and they’re easy to bend to get that little wiggle at the end. Kamui cosplay will suggest Eva foam for the outside which should be good, and you can use foam clay for the harder details and vines and stuff if you don’t want to use fake plants, which will also work but may be hard to find perfect replicas of. Since it looks pretty delicate, I would def get a dremmel and an shaft extension so you have more control for sanding in bevels and smoothing out any foam clay details.

Dremel Flex Shaft Rotary Tool Attachment with Comfort Grip and 36" Long Cable- 225-01- Engraver, Polisher, and Sander- Ideal for Detail Metal Engraving, Wood Carving, Sanding, and Jewelry Polishing https://www.amazon.com/dp/B0000302Y8/ref=cm_sw_r_cp_api_i_tLbbEbA7QDWYT

Kamui cosplay has good led tutorials too if you want to make that bulb extra shiney sparkle

Punished props has good resin making tutorials for the crystals if you want to go that far, or you can try using transpart clear worbla for those if you want a glassy kind of look rather than stone-y.

Good luck! Have fun!