How do I get the fly into the web?

Can't catch the fly and he just won't fly into the web on his own. Clicked on spider and web and nothing happens. What am I missing?

Hi there dancemom1,
SPOILER ALERT
Have you collected a plant that looks like a fan?
If so, place it on the RHS of the road in the cavern.
I hope this is helpful.
Cheers

There's an empty plant pot in the cavern that it can be placed in

After you plant the fern and catch the fly, it goes to the spider in the Enchanted Garden not the one in the cave.