An activity as apparently simple as gardening can raise quite a few issues of environmental ethics if you are going to be purist about it.
Putting in native plants is probably your first choice if you are to be ‘good’. But hold on. Do your choices grow naturally in your area?
Have the plants been eco-sourced? That is, did the seeds from which they were grown come from the same ecological district you are in? Auckland is divided into nine such districts, with the Rodney one starting at Okura and running northwards. You can ask your supplier where plants come from or collect seed yourself. It can be interesting to see what seedlings crop up in the unkempt corners of your garden of their own accord. My locality is suburban, but I still get rasp fern, lacebark, karo and coastal five-finger popping up all over.
I’m assuming you have not bought hybrids or cultivars. Heaven forbid! I have a lovely twiggy tree daisy in my garden that hasn’t looked so lovely since I figured out on NZ Plant Conservation Network that it is a hybrid even though sold to me as an Olearia lineata thoroughbred.
Bird lovers will often overlook the exotic origins of their plants if they are attracting native birds. I have bottlebrushes (who doesn’t?) that the tui love, and the wax eyes too, when the tui are not about. I suppose it’s a case of love the one you are with, as these Australian natives predate my residence. My excuse is that I am allowing karo to grow up through the bottlebrush, even though it won’t provide the same luscious nectar.
Linking plants with their pollinators can be a good way to design a garden. Fifty native species are visited by birds according to Auckland Council’s guide wheel Landscapes for Life. Of course, the plants don’t care if the birds are native or exotic so it’s not a route to an all-native garden. And you’ll miss out on scent. Few birds share our sense of smell, so the plants they pollinate, such as kowhai and puriri, don’t provide it. Lizards love a scent and nectar combination, but don’t care for colour. Kanuka and the various coprosma species suit them. Too bad, though, if it is the exotic rainbow skink that is attracted to your garden.
Everybody knows about monarch butterflies and the swan plants their caterpillars must have to nibble on. Oops, sorry. Swan plant is a native of Africa. Your monarch butterfly house may be pretty, but it is not native.
So you didn’t think you were a moral philosopher when you stepped outside with your gardening gloves on, did you? It is just as well that the leaves rustling in the breeze and the chirping of the birds uplifts us, whatever their origin may be.