I don't think petite is a height so much as a body shape. I have seen tall women shopping in the petite section because they have a short waist or shorter arms or wanted a skirt that fits them better than the regular ones, and I have seen smaller women shopping in the junior/misses/womens section for similar reasons.
Sweet clover needs a high pH, 6.0 or higher, for proper nodulation to occur, and it has a higher calcium requirement as well. Sweet clover is able to obtain phosphorus from relatively unavailable soil phosphates and will grow on soils where alfalfa, red clover or ladino will fail.
A great way to make a garden bed suitable for hostas and other plants is to till the soil to about depth of 18 inches and work in about 6 inches of organic matter. Adjust the pH, if necessary. Hostas like soil with a pH level of 5.5 to 6.5. Use pH testing strips, available at most nurseries, to test your soil. Then lower or raise the pH if necessary. Adding sulfur will lower the pH and adding lime will raise it.