Using Mimosa Leaves as Fertilizer?

In the South, the mimosa tree (Albizia julibrissins) is a common nitrogen-fixing species which is:

A: Constantly denigrated as being invasive

and

B: Never going away since it’s been here for hundreds of years and has integrated itself into the environment

So, why not use it for something?

I am currently reading Restoring the Soil by Roland Bunch. In it, he mentions a demonstration they have done for farmers in which a handful of Gliridicia sepium leaves are buried at the base of each cornstalk in a row of crops. The rest of the crops are left alone. After a short period of time, the corn with the leaves buried beneath it very obviously outgrows the non-leaf-fed corn around it, demonstrating the fertilizing power of nitrogen-fixing tree leaves.

Gliricidia is a very good nitrogen-fixing tree we used extensively for fencing down in the tropics. Unfortunately, it’s too cold to grow it here, so far as I know – but we have mimosa!

Hence our new experiment.

This morning, I picked a 5-gallon bucket full of mimosa leaves and spread them across half of a garden bed my daughter and I built for our fall vegetables.

First, we just laid the leaves on top of a loosened bed:

Then we just covered them all over with a little soil while the chickens watched and wondered what we were doing.

We used the soil from the paths and raked and shoveled it over the broad-forked bed in order to make it a raised mound, and to cover the leaves. Once they were covered, we planted the bed with a mixture of brassicas.

It will be interesting to see what happens.

I would also like to experiment with mimosa tree by using it as a replacement for Inga spp. in an Inga Alley Cropping system. Can you imagine two rows of mimosa, which could be repeatedly cut to feed and build the soil?

Stop wasting the “invasives!” Make them work for you!

Honestly, I don’t have enough years to live in order to do all the experiments I want to do. Let me know if you’ve tried using mimosa for anything interesting – I would love to hear about it. It’s an easy-to-grow fast source of nitrogen and carbon – and it’s everywhere, so we should get to work finding ways to use it.