Build a planter of wood or wall blocks. Dirt will just run out the rocks. Use those rocks to border around the planter, til & plant sod, seed won't work. Trees and evergreens for shade and garden height. Hostas (any, they do well in the sun here), lambs ear ( clump against the tall wall, purple flowers shoot out later, gray green leaf: very hardy and easy to break apart to replant), butterfly bush, all succulent ground covers (some with yellow:shown, or purple flowers are my favorite because I can separate and keep transplanting all over the yard. They spread amazingly) They also fill in between plants to keep soil moist. Iris, A gray leafed plant with white flowers (pictures everywhere), fills in as a base: roots itself to transplant. evergreen trees for shade, we have some apple trees or leaf trees. Day lilies are a sure thing, lupine, all perennials that produce a purple flower (but also attract many bees). Jupiter's beard is med height with reddish flowers. We live in Colorado about 7000ft. The soil stinks here too. Planter area next to grass approx 12x3. Added a bunch of mushroom compost. Dirt too light and dries out. Unfortunately, everything but the trees will disappear until next spring. Haven't tended to this garden yet due to hail and rain. But I will fill in with annuals for colors, like red not produced yearly. HOUZZ posted the patio photo. That would be perfect. Line at least your back fence with bamboo like others had suggested. That would be a great start!

Exactly as W states, mow and then cover with black plastic. Then I would think that the soil would have to be rototilled and large stems, deep roots, etc. removed. If they aren't removed then it seems to me that most of the hardier (deep rooted) weeds will just return. We just landscaped a bunch of our yard with xeric plants and we had to remove the tenacious plants like alfalfa (with roots from Colorado to China). We planted native prairie grasses in large swathes. Then in more controlled areas, planted big blocks of correopsis, jupiter's beard (valerian) and other hardy (mostly) native plants. You might check with a site like this for additional native plants in your area, although I can see that you are aware of some of them already: https://www.wildflower.org/collections/collection.php?collection=MA As the link shows (I picked MA), there's dozens of native plants, wildflowers and such that may work. Might be fun to have Eastern Redbud, Holly, or Serviceberry or a few larger shrubs as a foundation and then have the smaller perennials fill in? In this way you could show the students how to mix shade and sun-loving plants? Good luck!

Kathleen I googled that name and that's definitely what it appears to be! Thanks! I think I've seen seeds for red valerian around here before and supposedly that's another name for it. I ripped it out by the house foundation but for now I left it in the one adjoining garden where it also is growing. I like the idea of it attracting butterflies and other insects, so as long as I can keep it from growing against the house I'm happy :)

I have a blind side yard like yours. Hate it so much. I'd want to put in a gate so the area can be used for something. At the moment I'm growing a grape vine from corner of the house down the wall, a couple orphan succulents are back there and there are volunteer nasturtiums, Santa Barbara daisy and Jupiter's Beard. No irrigation and I weed in spring. Since there is zero summer rain it works okay but it sure is a waste. Like the idea of good sized cobbles best. A neighbor here has 2-3" cobbles in her large side yard that has remained weed free for the 30 years I've been here. The gardeners blow it clean weekly and that's all it takes. The stones are large enough they don't move around. No bother with watering! I would not put down weed barrier as it does no good whatsoever. I'd dig out the grass and maybe line with cardboard as it will rot out and be easy to deal with if you change the use of this area in the future then get some exercise laying down the large pebbles.