Marigolds are sun-loving, heat-tolerant plants. Grown as annuals, these colourful plants range from 6-inch miniatures to 36-inch tall plants. The flowers are variations of yellow, orange, red and multicolour. Use marigolds in landscapes as massed colour carpets, bright borders, companion container and accent plantings. Use marigolds for cut bouquets, edible flowers and herbal flavouring. Your marigolds attract outdoor pests as well as indoor guests.
Common insects such as aphids, whiteflies, mites and thrips feed on marigold foliage. Your marigold may lose its healthy green foliage and appear diseased. Look for these small insects under the leaves. They damage marigolds by feeding on the leaves and spreading disease. Large infestations kill marigolds. Control these insects by spraying vigorously with water. If insects return, spray or dust the marigolds with insecticide. Use food-safe insecticides if you are using marigolds as edible flowers.
Slugs love marigolds. Many gardeners plant marigolds along garden perimeters so that slugs devour this favoured fodder instead of vegetables. Slugs hide at the base or under the leaves of marigolds. Slugs and snails feed at night, leaving slime trails around the marigolds and shiny, mucus-like webbing over the flowers and foliage. Control slugs or snails by hand-picking, though this is rarely effective with heavy infestations. More reliable controls include non-toxic products such as iron phosphate granules or chemical controls containing metaldehyde.
Earwigs chew on marigolds. They eat holes in marigold leaves and kill young plants. Although the damage may look like slug damage, earwigs leave no slime trails. Lay a board near the plant and check under it over the next few days. If you find earwigs, use any bait, spray or powder insecticide that kills earwigs and is suited to your vegetation.
Rabbits munch marigolds. Although some gardeners claim marigolds repel rabbits, you may find rabbits devouring your marigolds. The marigolds, especially young marigolds, are bitten off at the stem. The clean, sharp cut is an indication that a rabbit found the marigold tasty. Rabbit poop piles or berries, those small round pea-sized manure pellets, are confirmation that rabbits stayed and fed on the plants. Solutions include netting over the marigolds, rabbit fencing, electric garden fence or wildlife repellents.
- University of Wisconsin Extension; Controlling Earwigs; A.J. Pellitteri; 1999
- Oregon State University Extension; Growing Your Own Vegetables - Protect Your Plants from Dreaded Slugs
- Iowa State University Extension; Rabbits in the Garden; Sherry Rindels; July 1996
- University of California Integrated Pest Management; Pests in Landscapes and Gardens -- Marigolds; 2009