It depends where you are. If you're heading to Hagrid's, then just walk right past them. If you're getting the Fire Seeds, you have to make them eat the bushes and make them fall into the holes in the ground. If you're looking for the sloth brain, just walk right past them.

PS: In the Fire Seeds Challenge, they can be affected by a Flipendo KnockBack Jinx. This is a bonus if you're working on the small hole and it's eaten a lot of bushes. They also produce about 5-7 Blue Bertie Bott's Every Flavor Beans per bush they eat.

ENJOY!!! :)

You can just walk past them. TIP: If you lead them to the bushes they will eat them and produce beans.