ljrd3, For the first year treat these as potted plants untill the roots grow into the surrounding soil. The water must go directly into the potting soil that came with the plant. Use 12th of a gallon per day if the temperature is in the 70"s. Use 1/6th of a gallon per day if the temperature is in the 80's. Use 1/4 of a gallon per day if the temperature is in the 90's. Delay one day for each 1/4 inch of natural rain. The second year use the same total amounts, however, you can begin to water less frequently using proportionally more each time and also watering a greater area around the plants.

Keep the weeds as long as they are helping with erosion. I'm doing the same thing with my new house. I have about the same slope 5 feet drop over a 90 foot run. St Augustine or bermuda will fill in relatively quickly, but they require practically opposite care. Decide now which you want. St Aug gets mowed at the highest setting while bermuda is mowed at the lowest. St Aug gets fertilized 3x per year and bermuda gets fertilized 12 times a year in FL. Both need 1 inch of water per week. Neither one requires additional top soil (You do realize that if you order top soil in Florida you get more sand, right?!). In my case I had a small amount of surviving St Augustine and 98% weeds. I'm only fertilizing the St Aug using organics. It looks great and is spreading well with the rain and cool weather we had in the spring. At this rate it will be a couple years before it's all St Aug. If I had dropped a few pieces of St Aug sod it would be covering much faster. So what I'm saying is if you want to go with St Aug, it is good in that it will overtake all the grassy plants/weeds you have. You could spend $10, place those pieces around, and let them grow together. It will take out some of the broadleaf weeds like dandelion, but not clover, dichondra, oxalis, or other "dollar weeds." Those would require chemical control with atrazine. But I would not spray anything until the St Augustine is filling in and then only where it is filled in pretty well. If you have fairly dense St Aug with spotty weeds, the atrazine will kill the weeds and allow the St Aug to fill in completely. If you decide to feed with chemical fertilizers, I would strongly suggest using an organic fertilizer at least once a year. You can never get enough organic matter in sand. Sand seems to eat it. Are you sure you have centipede? Centipede looks like St Augustine except centipede has pointed blades. St Aug has boat tailed shaped blade tips. Those two grasses need opposite care, too. Actually centipede needs no care. You can kill it with kindness without even thinking about it.

You have an admirable goal, but I am another soul that wants to weigh in on the side of caution as far as perhaps getting into a project that's potentially unmanageable. So I have a bunch of questions and comments as well as some links to add to what others have said. Can you get a group of volunteers to meet and help on a regular basis in maintaining this? I know the Peterborough NH parks' gardens are all volunteer maintained, but they meet once a week in the early morning for a few hours and there are several in the group. The man who is the designer and organizes the crew has a list of specific tasks each week. Here's a link to the part of his blog that discusses the setup of what he calls a public-private partnership, so the gardens were installed by the town dept. of public works, but are maintained by volunteers about whose work he occasionally writes. You can also click on each garden on the right side of the page for more info. His are more traditional looking gardens that what you are envisioning, but both need maintenance. One of his most useful pieces of advice to my mind is "Design only what you can maintain at the highest level. Long-term maintenance is the key." Are you interested in only native New England plants? It seems as though you want to include them, but also some hardy, low-care non-native perennials (Russian sage.) By nature, New England is naturally a forest, so does your goal include woody plants such as trees and shrubs? If not, you will have considerably more work removing woody plants that will try to move in courtesy of the natural ways plants seed themselves into new territory. The books of William Cullina (former director of the New England Wild Flower Society (NEWFS) and current director of the Coastal Maine Botanical Garden) will be of help in finding natives that suit your situation as will the many resources of the NEWFS. Because that is a cut bank, it is subsoil and not all plants will be happy there with low nutrients and fast drainage, so keep that in mind when choosing plants. You might want to get a soil test done. The area at the top will be much drier than that at the bottom, so plan and plant accordingly. Michael Gordon of Gardener's Eye says, "Prepare soil properly from the onset" which in your case (since you can't dig other than to plant on that slope) may include adding some slow release fertilizer, some compost and as Thyme2dig says above, mulch, lots of mulch. Mulch in the short term will discourage weed seeds from germinating and help maintain even moisture, and long term will add to the soil fertility. I would recommend either curls from a wood turner or chips from a tree service or the crews that maintain the local power lines since both will break down well and until them be more stable on the slope than some other mulch options, and either is free. Have you got the support of whomever does the maintenance for the rest of the property as well the administration? For instance, many of the plants you will want to use are spreaders, either by seed or by runners. If they seed over into the lawn in your photo, will that cause issues? As an example, my back field (quite nutrient poor, sandy acid loam on a very slight slope) has two of the grasses mentioned in the meadow kit from the NEWFS, Eragrostis spectabilis (purple lovegrass) and Schizachrium scoparium (little bluestem). Both are happy in the poor soil, generally low maintenance (the field gets mowed twice a year) and gorgeous in fall. In this photo the lovegrass is the broad swath of red-purple and the little bluestem is the darker, taller grass that shows in a couple of clumps near the edges of the lovegrass. Here's a photo of little bluestem from closer up taken on my way home today. As perhaps you can tell, it is growing in the sandy area along the edge of the road, so it's fine with poor soil. This is just the wild type, but you can also get named varieties that have more of the bluish tones or more of the reddish tones. I think it's really attractive. However, the lovegrass's seedheads behave like tumbleweed, shedding seed as they move, so I find lovegrass in the gravel drive, the veggie garden, etc. Another issue might be the maintenance crew weed whacking your garden, not realizing that it was a deliberate planting. I once had someone hedge prune a lovely shrub to a sheared blob in a public garden I had planted. Is there a water source to get plants established, either hoses from the school or a tank on a truck? All new plantings will be more successful if you can water them when rainfall isn't adequate. I don't want to discourage you, but setting realistic goals will be the key to your success. If there is a local garden club or other group that can be persuaded to see your vision and help consistently , all the better. Steps in order: -Figure out what's there, what can stay (I think I see a few shrubby white pines, for instance) and what to remove. -Create a design (including a plant list) that can be implemented in stages while still maintaining what has already been planted. -With whatever help you have available, implement the first stage. To give a sense of scale, a few years ago, I put in a large mixed perennial and shrub border that's probably 70'x15', working on my own, but with a tractor at my disposal, and the area had already been cleared. It took me 3 full seasons to plant: the first year doing prep, woody plants, and mulching for the first chunk; the second year adding perennials and adding another 15'x15' piece and the third year planting the additional piece and replacing plants that didn't do well from the first two seasons. So take creating it in chunks, but plan the whole thing before your start.

If erosion control is the main desire, you will want as many roots in the ground as possible. As suggested, put in the long term anchor plants (e.g. red-bud trees and cotoneaster ground cover), then plant flats of wildflowers for short term stabilization.