What causes the uproar when Catherine and Hareton rearrange the garden at Wuthering Heights in Chapter 33?

Cathy convinces Hareton to cut down a patch of berry bushes so that she can put in some plants from the Grange in their place. Joseph becomes furious about his uprooted plants and everyone argues. Heathcliff grabs Cathy and is about to hurt her when he unexpectedly let her go; he then sends them all away, wanting to be alone.