What is this and where in my yard would it look and thrive best? Shade? Full...
This looks like Malva sylvestris 'Zebrina', a hollyhock. This is a beautiful biennial plant that grows to 3' high and blooms throughout the growing season. They are commonly grown as annuals and tend to decline after several years. They do reseed themselves and may perform like perennials.
Hollyhocks can be susceptible to rust, a fungal disease. Hollyhocks should be planted in areas with good air circulation. Good fall clean-up is important, cut the plants back to ground level. When watering avoid wetting the foliage and place a 1-2 inch layer of mulch underneath the plants. See our Plant Diagnostic website http://plantdiagnostics.umd.edu/level3.cfm?causeID=351
Hollyhocks grow best in full sun in a moist well drained soil. Provide good air circulation.