Marigolds Live Flower Plants are one of the most popular annuals worldwide. But, these plants are not only known for their striking colors and abundant flowers. They also have tons of uses and benefits, from health to pest control and more. 1) Marigolds Are Easy To Grow First and foremost, most types of Marigolds are incredibly easy to grow and are generally considered rapid bloomers from seed. They flower prolifically without much additional maintenance and rarely give their owners any serious trouble. Placed in the right spot and given some basic care, they will thrive from spring until fall (for more, see our guide to marigold growth expectations). Place them in a full sun position, give them sufficient water and moderately fertile soil and they grow to their full potential. Avoid shady areas which impact blooming and lead to the growth of powdery mildew. 2) Marigolds Repel Certain Pests The pest repellent qualities of Marigolds are one of the most often repeated benefits of these plants. But some aspects of their repellent characteristics are better researched than others. What does seem to have scientific backing is that Marigolds repel whiteflies. A University of Newcastle study found that Marigolds protect tomato crops because they naturally disperse a chemical known as limonene into the surrounding air. The insects hate the smell of limonene and stay away from the Marigolds, as well as any nearby plants. Even better, because limonene repels the whiteflies without killing them, they won’t develop a resistance to it. Marigolds can also control certain parasitic nematodes. Nematodes are microscopic worms that feed on the roots of plants, damaging essential plant systems and ultimately leading to their demise. Studies show that the Marigold roots release alpha-terthienyl, a toxic chemical that inhibits the hatching of the nematode eggs.