A purple maxi dress flatters every shape and skin tone, and works for any occasion at any time of year. 2018 trends for plus sizes look fantastic with solid or patterned designs. A simple cotton purple sheath dress can look casual enough for the beach or a picnic. If you are preparing to attend a wedding choose a satin material to achieve a formal appearance. The flattering gradient dress slims the figure with deep purple on the top and pale lavender on the bottom.