Caesalpinia gilliesii, the Desert Bird-of-Paradise, is a spectacular plant. It is native to South America but is naturalized throughout the Southwest. It would probably grow in other places. It thrives on our alkaline soil, baking desert sun, and low rainfall. It’s gorgeous in bloom and neat-looking when not in bloom. It seeds itself around but is easily eradicated where not wanted. It provides filtered shade to other plants. And it fixes nitrogen. Quite a set of advantages.
I’m making use of it on a dry, hot, unirrigated strip of south-facing land along my driveway where I want to grow goji berries. The goji plants struggled and mostly died at first, but as seed-sown bird-of-paradise takes hold and provides them with some shade and nitrogen, the gojis are getting a new lease on life and have finally put out some berries. I trudge the hose over and give everything a deep soaking about once every 3-4 weeks.
For years I struggled with Caragena arborescans, which is the darling of the permaculturists but simply will not grow well, or at all, for me. Now I have Caesalpinia instead. No part of it is edible but it helps edibles grow. It has survived 10 degrees Fahrenheit with no problems. In Britian they do have hardiness issues with it, and I think it won’t tolerate wet feet. For dry gardens it works beautifully.
So look around you and see what nitrogen-fixers thrive in your area and grow without pampering. Use them. Don’t fuss with the ones that are determined to die.