Iris are generally planted 12 to 24 inches apart. Close planting gives an immediate effect, but closely planted iris will need to be thinned often. Plants spaced further apart will need less frequent thinning. Many people plant them in small groups of say, three or five or seven; to give a massed effect. Newly set iris need moisture to help their root systems become established. Specific watering information depends on your climate and your soil, but remember that deep watering at long intervals is better than more frequent shallow waterings. Once established, iris normally don't need to be watered except in really dry areas. Overwatering is not desirable, but many people make this mistake. Specific fertilizer recommendations depend on your soil type, but generally an all-purpose food or a 6-10-10 are the way to go; just keep it low in nitrogen. A light application in the early spring and another application about a month after bloom is a good idea. Avoid using anything high in nitrogen, as nitrogen encourages rot. You can also give one more light feed after the growing season in order to encourage healthy growth for the next season. You will need to divide your iris before they become overcrowded, generally every 3-4 years. If too crowded the bloom will suffer, some varieties may crowd others out, and disease problems may be occur. Old clumps may be thinned by removing the old divisions at the centers of the clumps and leaving new growth in the ground. Or, you may dig up the entire clump and repalnt wiht the smaller, new, and healthier ones.

Along with your criteria of low maintenance, high privacy and very inexpensive you may also want to consider using plants that are practical around a swimming pool, this means plants that are relatively clean in regards to shedding or have large leaves that are easy to pick up and won't clog an intake filter like lots of small falling flowers and leaves do. Several palms are fairly clean in regards to shedding and can give you some privacy. As far as the expense goes, I suppose that is a relative term. Some varieties to research would be Trachycarpus fortunei, Chamaerops humilis and Syagrus queen palm. You could do a dense planting of cannas between the trunks and might even have room for some succulents. If palms are not your thing then you might consider some large espalier type trees such as Magnolia little Gem or possibly some narrow growing hedge plants such as pittosporums or podocarpus I think it would be a good idea to visit your local nursery and see what they have to recommend for your particular neighborhood/ climate zone.

Please don't count this as expertise--just one season's experience with sweet potatoes. I planted some last year near the end of July (also downtown ABQ, morning sun) and by frost had a number of fingerlings. I just set an entire potato in the soil--the eyes had already sprouted, and the potato leafed out in a matter of days. Somewhere or other I've read that it's not a good idea to cut up a sweet potato and plant the eyes like you would a white potato--don't remember exactly why, but fungus or bacteria or rot or something like that played a part. For what it's worth, the leaves of sweet potatoes are also edible--they taste a little "starchy," but they make a fine addition to a salad and are packed with vitamins. If you don't get actual potatoes, at least you can have some dark leafy greens! They're also lovely plants--worth growing on their own.

Your wanting to do the whole 3.75 acre? You do say if you want to landscape this area or not but if it was mine I would take the larger area and let nature have it back. Purchase some wildflower seeds and throw them about the whole area. There is a mix of spring, summer and fall plants. Also look up LadyBird wild flower farm. If you order now you'll be able to spread poppies, blue bonnets and other wildflower seed in time for spring. Here is a link that might be useful: wildflower, wild flower seed, native wildflowers from wildseed farms