Mulches can help prevent soil erosion by 1) slowing the fall of rain and spreading that out more, and 2) by keeping the wind from picking up soil particles and moving them around. Compost and other types of organic matter can be laid down on top of the soil and, eventually, the Soil Food Web will move that material into the soil for you. That mix will be better all around than you can by tilling the same material in with much less effort on our part, however, this is just not as fast as you can, better just not as fast. Soil warming may be somewhat dependant on what soil type you have. My sand warms in the spring with no problem even when covered with a thick mulch layer. I have seen no problem with plants growing when they are supposed to and some people I correspond with around the world report the same experience while a few do say they need to pull back the mulch to warm the soil. But if you have a planting bed covered with mulch and you pull back a 6 inch wide swath to plant in does logic tell you that the soil in that bed will really warm up enough to encourage plant growth? If you removed all of the mulch that probably would happen and the soil moisture would be evaporated faster drying the soil out more. As a rule organic matter in soil will alter the structure so that in clay type soils water will move more freely while in sandy soils water will be held in the soil longer, but this has no affect on your water table. The water table is where the water flowing through your soil is at various times during the year and in the snow belt that rises, normally, in the spring and then falls during the dryer summer. There is always water flowing under your feet, even in the desert, even though it may be many feet down. That water table, the aquifer, is where those of us with wells get our water from. Adding organic matter to your soil will have no affect on where your water table is at any given time, that is determined by how much water is flowing through your soil from all around you. Oats and many other grains are reputed to have allelopathic properties (growth suppressing), while they are growing but may not keep that property once cut down, although some seem to do just that for a time. Some research seems to indicate that the more organic matter in the soil the stronger this property is.

English Ivy can be very invasive in some areas. I suspect those who questioned how good it is for erosion control were thinking of areas where it out competed something better Many experts say grass...particularly American Beach Grass and perennial Beach Grass...is the best sort of plant for erosion control. Vines are often good for erosion control. I'm fond Trumpet Vine but others consider it too aggressive. Plants that are adapted to grow on beaches are good for erosion control...eg. Virginia Rose, Bearberry, Jersey Tea etc. Lowbush Blueberry is decent for erosion control, and is often found naturally on cliffs. Why do you think plants die there? What is your soil like? Wet or dry? Clay or sand?

Thanks all for the suggestions! I probably should have explained better in the first place. House is up on a naturally forming slope, with the asphalt driveway rising steeply to meet in. After the snow melted, we noticed that what had been shallow-rooted grass off to the side driveway apex was now about an inch lower, bald, rocky, and pocked with ridges from the water runoff. This area extends ~1-2 feet horizontally before dropping down ~4 feet at a ~45 degree angle. Our idea had been to cut a "L" in the side of the slope, reinforce the earthen backstop with a small rock wall, and level the top area with soil, in effect creating a bit of a terrace for the slope to slow down what we worried might erode more in the coming years (which could eat away the earthen support under the asphalt in our paranoid minds). In the soil up top (we would supplement the dry, rocky, clay) we hoped to plant something pretty-- enough to bring color and foliage most of the year and anchor the top soil a bit. As it was to be to the side of the drive, we were hoping for something with a little vertical height, which might act as a natural flag during winter (as we learned the hard way this year, when the hired plowman drove off the driveway and over a small cobblestone ringed flowerbed buried under the snow). We saw heather at a nursery the prior weekend and thought it looked pretty, offered a little height, and might look nice on a hillside here and also in another part of the yard. Thanks again and hope the description was more helpful (sorry--- haven't figured out how to post pics yet)

Are the trees' roots exposed or are those mostly rocks? You want something that stays close to the ground to absorb the impact of the water. With shade your choices may be somewhat limited. Vinca is ubiquitous around here. You can plant other little plants in between. Various wild geraniums are popular around here, and liriope, perhaps some ferns. I had a plant called sweet woodruff covering the ground in the shade at my last place, very pretty in the spring. Some other classics are small bleeding hearts and ajuga, (actually anything in the mint family, like native mountain mint or horsemint which you can grow from seed) and perhaps some thymes although they need a bit more sun, also woodland strawberry and virginia creeper are natives that are used and there is a dwarf goat's beard that is beautiful. Yarrow is good in partly sunny areas. Someone on here once told me about creating little pockets of good soil surrounded by rocks. I see you are good with the idea of trying to spread that water from your drainpipes out as much as you can instead of concentrating it. A good thing to do is create pockets where the rainwater can be absorbed to control the erosion, but the trees roots run contrary to that objective. I would just try planting things and see what takes off. That's what I do on my hillsides, just keep trying to get vegetation established. We use natural wood chips too, to hold down the soil.