Similar to perennials, there are some confusing labels out there that need to be clarified, particularly for Californian designers. Namely, what is classified as an annual in other parts of the country may in fact be treated as a perennials here. Some examples are cyclamens, fibrous begonias, chrysanthemums, and petunias. In each case, their return from seasonal dormancy can be highly variable, but if well cared for, they can reemerge and perform for multiple years. For the plants noted above, I have successfully grown each of these way beyond one season into several years, in part by allowing them to remain in place, go through their dormant periods without excessive care, and they rewarded me with a showy return. Gerber daisies and even primroses have also performed this way, although once again with mixed results. For designers, this often is a moot point; their mission is for plant compositions to flourish and have little to no downtime. But if you are someone willing to set such plants aside and wait for their return, then look within this category for those plants that are categorized as annuals but may actually be perennials for our mild climates.
Numerous species, such as the zinnias and sunflowers listed here are indeed annuals. Their mission in their short lives is to indulge in blooms, mostly for pollinators, and produce sufficient seeds to replace themselves next year. In California, we have annuals for all seasons, and for designers, that means specifying a rotation of color depending upon clients' budgets. The rotations, meaning replacing plants when they die off, can be as often as necessary to maintain a lush appearance, but for most it might be either quarterly or as little as annually for one specific season. A rotation schedule for a shady planting area might look like this for a quarterly replant:
Sunny locations would be different species, and clients may prefer fewer rotations. For example, some clients with country estates may only want summer annuals when they are on vacation. What this means for designers specifying annuals, consider frequency, location, and budget to know the best options.