 You can also use them to fill in empty spaces or complement existing perennials. Some annuals offer benefits to perennials like deterring pests or enhancing soil health. Annuals like marigold are adored by humans but despised by pests. Finally, pollinators love them. Many annuals attract bees, butterflies, and other beneficial insects, which is important to create biodiversity. Plant a few in your veggie garden to boost productivity.