I would agree that sod isn't going to solve your problem, but the right vegetation (deep fibrous rooted grasses) in combination with the right erosion control products can protect some of the steepest banks from continued erosion. But you do need someone who understands soil stabilization. Personally, as a Civil Engineer, I would stay away from rocks. Rocks are too heavy and can aggravate the problem. If I were you I would find out who the sales representative for North American Green Products is in your area. Usually their sales reps can be very helpful. (I don't work for NA Green, but I use their products frequently.) You probably need some coir logs, some turf reinforcement mats and a proper seeding mix for your area. And you probably will have to remove a few of cypress trees. And you probably don't want to hear this, but I would expect that the cypress trees probably played a role in aggravating the erosion problem.... Here is a link that might be useful: North American Green

IF it is appropriate to fertilize (and that can only be determined by a soil test or the plants indicating an obvious need), then the fall is an excellent time to do so, especially with hardy woody plants. Roots are in a period of active growth at that time and it has been documented that they are more able to access and metabolize nutrients then than at most other times of the growing season. You just want to avoid a high nitrogen fertilizer -- pretty much anything organic would work. Although I would never say NEVER (ken, ken, ken!!), established trees and shrubs seldom require supplemental fertilizing unless soil pH is marginal and chlorotic conditions develop. Anything applied to the top of the soil surface can be considered a 'mulch', although organic mulches like bark OR compost (or leaves, grass clippings, wood chips, etc.) are preferred and compost will provide an excellent, well-rounded, low grade nutrient source. If you mulch with compost regularly, you may NEVER (and I qualified that with a "may", ken!!) need to fertilize :-)

I was thinking that but the crab apples I am familiar with have larger fruits (the largest of these were under 1/2 inch). The seeds are definitely apple seed-like, but the fruits more like berries than even the smallest of apples and they are basically rotting on the trees, accounting for the change in color. I seem to recall the crab apple tree in my backyard as a child would shed the apples to the ground. I also don't recall the leaves being serrated, but smooth edged. Obviously I know nothing of tree families and similarities or cultivars to make any kind of judgement. :) I am learning though!

Steve, I've solved this problem many times and I hope this solution works for you. 1..purchase the rubber or plastic garden edging that is about 4 inches deep. Install it along the entire length of the driveway, snug against the concrete. It will come in sections and can be fitted together. 2...Now on the outer edge, add decorative stone, crusher run, river rock...which ever you like best but DON'T use P-gravel. Come out at least 6 inches and 2 inches deep and lightly tamp it in.. This will serve to break up the stream of water and minimize the erosion effect. The thin bead on top of the edging will nicely define the edge of the driveway and guide the water nicely down the edges of the driveway, that falls onto the concrete itself. The other side of the edging will guide the water down without letting any to wash out under the driveway. I like this because you can ride over it with a mower to go from one side of the driveway to the other without hitting the rocks or edging with the blade. If the look of stone doesn't appeal to you, you can plant a low growing plant, such as Periwinkle (stays green all winter too).