Establishing a food forest amongst aggressive grasses

This spring we broke ground on an exciting new community food forest here in Detroit, MI. We had certain limitations and time constraints that forced much of the establishment in a less than ideal manor. The site is about 3 acres and will eventually have over 100 trees on the edge of a mostly healthy floodplain forest that's part of a 300 acre park, which is part of a much larger wildlife corridor that extends for miles more or less undeveloped. The slope is gentle but we planted the trees on contour. The design involves a 125 meter swale through the center, which was not dug at planting time due to a wedding happening on the same site in the spring. The trees were purchased with a grant with a quick deadline to be spent, and were mostly small, bare root and had to be planted within a week of arrival. We made mulch circles around each tree and put each in tree tubes.

Ideally we wouldn't plant trees, but plant an ecosystem...but that didn't happen. The area is much too large to sheet mulch. Chickens and other animals aren't an option because this is a permies, exposed site. I'm wondering the best way to plant the groundcovers and other layers in the midst of very competitive grasses. We've considered Martin Crawford's technique of killing the grasses with fabric (solarizing). Weve consider extending the mulch circles each year around each tree until the cirlces connect and the grass is supressed. And we've considered tilling and planting buckwheat or other fast growing, alleopathic cover crop that could be mowed down or winter killed as mulch. Looking for any other advice on getting this established. Some of the most difficult vectors/considerations include heavy deer pressure, theft and vandalism by bored neighborhood kids, lack of financial resources for established groundcovers  (though we can afford covercrop/green manure seed). We also have access to a lot of volunteers for labor. Thanks!

Ps im one of rhamis' students from his first course.

Buckwheat is a vine and would grow up your baby trees. I have done a simular poroject where I laid down some cardboard and put 4" of topsoil on top - within 2 years you'd never know I tried to get rid of the grass.

Killing the grass with plastic would be good, but would take a while. A year after burying the sod under cardboard, the sod was still dormant and viable and trying to grow.

I'd recommend mulching with large chips (not the fine ones), putting a trunk guard around the baby trees (http://www.landplan.com.au/Tree-Guards/SpringWrap-full-wrap-tree-guard.aspx?id=38&c=9), then using a weed burner occasionally to keep the grass from getting the upper hand. The grass will grow right through mulch unless the mulch is so thick it blocks all oxygen to the grass roots, in which case it would do the same to your poor trees.

I'd also recommend a clever irrigation system be installed where you bundle some 1/4" or so suckers (apple works great, nice and straight) into 2' to 3' bundles. Leave a few inches of this bundle sticking out of the ground, and plant next to your tree. When you water, pour the water down the bundle of sticks. The surface water quickly drains down this hole, and doesn't provide as much water for the grass. Even better is to use 2' PVC pipe with several tiny holes drilled in it pointed towards the tree (agroforestry.net/pubs/Deep%20pipe%20irrigation.pdf). I use this system with the PVC and it works great.

Buckwheat is great as a ground cover. Mine reaches two to three feet in good soil and much less in poor soil but comes up fast and the bees find it at any height. I've never heard of a vining buckwheat as Jon mentioned. My problem this summer was cardinals and other birds eatting the seeds before it could sprout. I finally laid thorny branches over the bed and it is up fine. Deer and bunnies will nibble if they are hungry though. I love the sound of your project.

There is another thread "grasses invading my mulch" I think that had a lot of good advice on keeping back bermuda especially.

i'm also in Michigan so your aggressive grasses will be the same as mine, and aggressive they are.

how I do it is I clear all the sod out of the area around the tree I'm going to plant..plant the tree, pop in a comfrey root piece next to the tree, also some rhubarb if you have it..for heavy mulch..pop in some other plants that are quite aggressively growing in the circle and IF YOU HAVED IT AVAILBLE put in a barrier..in a circle around the tree base..if not..find all the mulch you can get and pile it up around the area..leaving a few inches at the trunk of the tree so mice don't nest and chew.

with 100 trees this might be daunting so see if you can get some help from a local group of some kind..girlscouts, church groups, ymca, whatever..newspaper is cheap and will help to keep the grass down but you gotta pull it if it comes back aggressively thru the mulch, pull after a good soaking rain.

we have neighbors living in detroit and we might be able to send you some baby trees next spring from our woods..seedlings of maple or others..PM me so we can keep in touch re your needs.. I also could send you starts of jerusalem artichokes and maybe some bits of comfrey and rhubarb..

I am working on a site in Michigan that has heavy clay ground in a wetland area. In preparation for planting fruit and nut trees, I am hand spreading red clover and turnip seed. I have existing grasses (rye?) mixing with cattails near the wet areas. I can't tell you how it works yet but that is the conclusion I came to. Time will tell if the clover can take over from the grasses. Turnip seed is very cheap, I am hoping that the tap roots will open up the clay soil. I don't intend to harvest them, just leave them to rot in the soil.

Next spring I may plant bush beans to see if they can take over from the grass.

I think sheet mulching around each tree is a good option. You could also surround each tree with vetiver grass which I have read will prevent the spread of other grasses. Vetiver is cheap, easy to propagate and will improve the soil with its massive fibrous root system. It makes some of the best mulch and it protects plants around it from insect damage. It also acts as a wind break protecting young trees. You may have to cut the vetiver down eventually to allow the trees roots to spread but this will only add a bunch of organic matter to your system and by this time the trees should be large enough to compete with any grass... if you haven't already replaced it with something more useful.

I would use sheet mulch around the trees and cardboard underneath thick, black plastic everywhere else. I'd leave the cardboard/plastic cover for two years except where you want to start a new guild or improve an existing one. I've seen the plastic/cardboard combination work well in Montana.

Thanks for the good ideas. The most obnoxious grass on the site is the "quack grass". Basically nasty little buggers that spread by rhizome and will regenerate if the littlest piece is left. The trees that are surviving this nasty drought of a year (we've had some nice rain lately), are doing fine. We removed about 3-6 foot circles of the sod and mulched thickly with woodchips and some grass clippings. Making these circles expand to cover the whole space would encompass 2-3 acres of sheet mulch. The amount of organic matter that would need to be gathered is overwhelming, nevermind the install! The main thing is, we want the grass to more or less go away in place of more useful herb and shrub layer plants under our trees. It seems like plastic may be the way to go...

As far as sharing plants are concerned, I'd mostly be interested in edible or support species like the comfrey or sunchokes. The floodplain forest it connects to has tons of black walnut, black locust, hickory, and sugar maple seedlings that can be moved out if need be. I'm especially in need of shrubs...thinking all the ribes and rubus cultivars, as well as hazels and any other shrub/ground fruits

Hey um just for your information, in case you ever come across someone who may be in this situation some day.

Right now im struggling trying to find quack grass root for tea, it's one of the 3 key ingredients in treating bladder stones and infections in dogs and humans.
One place has the tea and it's some swank organic shop 3 cities away, I dug up all the different long grasses I could find but no match.

We've got to get her to dissolve and pass these stones or the only alternative is surgery. I watched the surgery and im not a fan of having my lady's bladder reamed out with a tea spoon.

Everything has a purpose, even if it's on the other side of the country or globe where mountain water gives people high uric ph.

Now someone help me find people who need creeping buttercups by the barrels.

How about some type of eleagnus in between the trees? Shade wins in the end.