Planting annuals later in the season

Of course you can plant later in the season! Plant and replant all summer long if you want and into fall if you garden in a mild climate. As long as the plants are willing and able to grow and produce flowers, why not? Because blazing hot weather is stressful, avoid planting during such spells or at least coddle the newcomers with plentiful water and some sheltering shade until they get established. A dose of all-purpose fertilizer (applied according to the instructions and rates on the container) may also hasten latecomers along.