The 12 Chilean Mesquites (Prosopis chilensis) in my garden have formed their beans, and by June, tons of ripe beans will be littering my landscape. We chose the Chilean Mesquites because they are very fast growing and we needed shade quickly. In hindsight, I realize that having so many is going to present more than a few problems, not only because of the litter, but also as they mature they will need major pruning that we will not be able to do ourselves. Our mesquites are already too tall to pick the unripe beans while they are still in bunches. As the beans ripen, they will drop individually, so I will have to wait until then to start the cleanup--just in time for the sweltering monsoon season! If I had any interest in using the beans, Desert Harvesters provides some neat facts about mesquites, and ways to use mesquite bean flour in recipes.
I have two other tree varieties in my landscape, and they too are very messy. The Desert Museum Palo Verdes, (Parkinsonia Hybrid 'Desert Museum') are advertised as low litter, but they are long and heavy bloomers and the dried flowers around the trees are an inch deep right now! Willow Acacia, (Acacia salicina) drops pods and seeds all summer, and then its dried little puff balls in fall and winter. All this litter dropped on gravel is tough to clean up. Unfortunately, I like a litter-free landscape!