Angus, I’ve had good results growing Sunn hemp. The nodulation on some plants was very impressive (clusters) but on others slight. I assumed this meant an inoculum was necessary, so added it to a recent planting. I have a citrus grove of young trees. 4-5’ tall hemp with bright flowers on top was enjoyable to watch In a breeze. I let it go too long and the stem becomes very woody and can’t be mowed. Cutting at early flowering would probably be ideal. Mine was a part of multi-species cover, so was widely spaced.