living mulch under oaks zone 5b

Hi,

I am a college student very interested in permaculture and I will be starting my own small farm this spring in zone 7. However, I currently have an assignment where I am supposed to design a living mulch project for a grove of oaks in my school's arboretum. The assignment asks "Develop a plan to create a “Living Mulch” (LM) that suppresses weeds, retains soil moisture, maintains and/or enhances beneficial microbial activity via decomposition, nitrogen fixation etc...  LM not to focus on ornamental garden plants or aesthetic norms..  Naturalized and native species produce fantastic blooms and shall remain, controlled, on-site if possible.  Must achieve maximum results with minimal maintenance."

I was wondering if anyone had any advice for possible plants to use. I wasn't sure because it is almost full shade underneath the trees. Any advice would be great.

Thanks,

Sam

For me most living mulch/cover crop, should have the following things.
Legume Family 80% (Dutch Clover)
Dandelion/Sunflower Family
Onion/Garlic Family
Thyme/Mint Family
Dill/Carrot Family

In theory some grass family should be in it to add a source of carbon. But to me the tree (oaks/fruits) already fulfill that role.
If the trees were spread farm away. I could think of this as a type of pasture with 40% legumes, 20% herbs/forbs/flower and 40% grass family.  

I like like daikon radish alot, if there was a need to focus on soil aeration,  

Hosta will thrive in shade and will bloom, but unsure of other requirements like nitrogen fixation.

Any of the edible honeysuckles, autumn olive, dogwood, hawthorn, sumac, blueberry, serviceberry, spicebush

Austrian winter pea, vetch, buckwheat, violets, cranesbill, geraniums, bladder campion, trefoils, goldenseal, echinacea

Chufa, dewberry, strawberry, gooseberry.....

A few things that I see growing naturally in my 5b oak forest.