One of the definitions of nursery is:
a place or natural habitat that breeds or supports animals
And going on that, my garden is a bit of a nursery just now because there are caterpillars living on my one and only parsley plant that will turn into black swallowtail butterflies! They are called parsley worms, though they'll also live off dill or carrots. I counted six, but didn't move the plant leaves to see if there were any others. You may read more about them here. In all my years of gardening, I've not seen them or heard of them before now.