Marigolds are known for their resistance to pests, disease, and hungry critters, so they are frequently used as a companion plant in vegetable gardens or herb pots. However, they also make a lovely addition to a sunny summer or fall planter or annual bed. These tough plants generally stay below 10 inches tall and are available in various shades of orange and yellow. Marigolds do not require much fertilizer and they benefit from regular deadheading to keep them blooming all season long.