Marigolds: Efficient Aphid Repellents in the World of Companion Planting - Unveiling the Facts
In the realm of gardening, marigolds have long been a beloved addition to many a floral display. These bright, cheery flowers not only bring a splash of colour to any garden but also offer a host of practical benefits, particularly in the realm of pest control.
Three main types of marigolds are commonly found: African Marigolds (Tagetes erecta), French Marigolds (Tagetes patula), and English or Pot Marigolds (Calendula genus). Each type has its distinct characteristics and pest-repellent capabilities.
African Marigolds, such as Kilimanjaro White, are tall plants, reaching approximately 18 inches in height, and boast large 2–3-inch blooms. Native to Mexico and South America, these marigolds are drought tolerant and attract pollinators and butterflies. They also have an edible flower with a citrusy/spice flavour. African Marigolds are useful in container or flower border settings and are known to repel nematodes in the soil, although their pest-repellent capabilities are less commonly cited compared to French marigolds.
French Marigolds, like Naughty Marietta, Burning Embers, and Cinnabar, are smaller, bushy plants that range in height from 8 to 50 inches, depending on the variety. They offer a plethora of colour variations and sizes, making them ideal for borders and container plantings on porches or patios. French Marigolds are hardy annuals with edible but pungent flowers, and they are particularly valued for their strong ability to repel nematodes, aphids, whiteflies, beetles, caterpillars, and root-knot nematodes. Their pungent scent acts as a natural insect deterrent, and they are often planted near vegetables like broccoli, potatoes, and lettuce to reduce pest damage.
English or Pot Marigolds, while not a Tagetes species, are commonly called marigolds and are used more for ornamental and culinary purposes. They are less known for their pest-repellent effects compared to the Tagetes species.
Marigolds produce chemical compounds in their roots and foliage that repel nematodes, aphids, whiteflies, slugs, and various beetles and caterpillars. French marigolds are especially valued for interplanting with crops like broccoli, potatoes, and lettuce to reduce harmful beetles, root-knot nematodes, slugs, and rabbits, enhancing crop health without chemical pesticides.
For integrated pest management, growing a mix of these marigold types around key crops can provide diverse pest-repellent benefits and attract beneficial insects like pollinators and butterflies. For example, marigolds combined with lavender are known to drive away moths and fleas while attracting bees. Similarly, marigolds enhance growth and repel flies and mosquitoes when combined with basil.
In addition to their pest-repelling properties, marigolds also have practical uses in the garden. African marigolds prefer cooler autumn temperatures, which intensifies their colour and extends their blooming time until frost. They make a bright, welcome mat of colour at the garden's edge or perimeter.
However, it's important to note that not all plants play nicely together. Beans may hinder the growth of marigolds, and marigolds can repel potato beetles when planted with potatoes. Marigolds also help deter carrot flies when planted with carrots.
In conclusion, French marigolds (Tagetes patula) are the most widely recognised for their pest-repellent capabilities, particularly against nematodes and common insect pests in vegetable gardens. African marigolds (Tagetes erecta) contribute as pest deterrents but are more decorative with some drought tolerance. English/Pot marigolds are less prominent for pest control.
By incorporating marigolds into your garden, you can enjoy a vibrant, colourful display while also protecting your plants from a variety of pests. Happy gardening!
[1] University of California Agriculture and Natural Resources. (n.d.). Marigolds. Retrieved from https://ucanr.edu/sites/Marigolds/ [2] National Gardening Association. (2016). Marigolds: The Pest-Repelling Powerhouse. Retrieved from https://www.gardeningknowhow.com/garden-how-to/beneficial/marigolds-pest-repelling-powerhouse.htm [3] Royal Horticultural Society. (2021). Marigold. Retrieved from https://www.rhs.org.uk/plants/25358/Marigold [4] Cornell University Cooperative Extension. (2017). Marigolds: The Pest-Repelling Powerhouse. Retrieved from https://blogs.cornell.edu/vegetablemd/2017/04/18/marigolds-the-pest-repelling-powerhouse/ [5] University of Illinois Extension. (2021). Marigolds. Retrieved from https://web.extension.illinois.edu/cfivt/marigolds.cfm
Embracing companion planting strategies, gardeners can incorporate various marigold types, such as African, French, and English/Pot marigolds, into their home-and-garden lifestyle to enhance overall plant health and improve the aesthetics of their gardens. This diverse planting arrangement may further contribute to strengthening the ecosystem by attracting beneficial insects like pollinators and butterflies.
In the realm of gardening and pest control, the French marigold (Tagetes patula) is recognized as the most effective in repelling nematodes and common insect pests typically found in vegetable gardens. Marigolds' pungent scent also acts as a natural insect deterrent, making them an ideal choice for container and border gardening, as well as for improving the lifestyle, health, and beauty of any home-and-garden enthusiast.
