Gardening is not always fun. After diligently tending to warm season vegetables through spring and summer, it eventually becomes necessary to pull them up to relinquish space for cool season vegetables that grow through autumn and winter. It likely would be less unpleasant to wait for them to succumb to frost, but by that time, it would be getting late for the incoming vegetable plants.
Removing warm season annuals and bedding plants is just as necessary, and might be just as unpleasant. The only consolation is that the incoming cool season annuals and bedding plants are likely to be blooming well as they get installed. Even though they take a while to mature, there is no time without at least some degree of color. Warm season annuals may be tired by now anyway.
Just like cool season vegetable plants, the various cool season annuals and bedding plants appreciate an early start so that they can begin to disperse roots while the soil is still somewhat warm. Only those that dislike warmth should wait. Cyclamen and flowering cabbage and kale can be planted as late as winter. Flowering cabbage and kale might even bolt if they get too warm too soon.
Pansy, viola, sweet William, stock, Iceland poppy, calendula and various primroses are all seasonable now. They should be happy to bloom until they too need to be replaced by annuals for the following season, several months later. Chrysanthemum, marigold and a few other autumn annuals are short term annuals that bloom excellently through autumn, but are not likely to bloom later.
Just like most of the cool season vegetables, most of the cool season annuals should be planted as small seedlings in cell pack. Chrysanthemum and many of the primroses, as well as cyclamen and flowering cabbage and kale that come later, should actually be planted as four inch potted plants. Needless to say, some of these are expensive relative to their respectively limited bloom seasons. Seed for nasturtium and alyssum can be sown directly into the garden. Nasturtiums seedlings in cell packs are expensive and do not transplant well.