Tip of the Day: Are Marigolds the Wonder Flower?
Can Planting Marigolds Keep Your Garden Pest-Free?
April 21, 2011— -- Some call Marigolds a wonder flower, but do they really help keep you garden pest free? Can they really repel and kill plant pests?
If you really want their pest-controlling benefits, blanket your garden with oodles of marigolds. British studies showed that African marigolds killed weeds such as ground ivy and bindweed. But the marigolds were planted densely and early in the season and then allowed to grow 5 feet tall. Might not any tall, dense growth do the same? Additionally, marigolds suppress nematodes only when the marigolds are grown as a cover crop, that is, planted thickly and allowed to grow for many weeks.
To sum up, marigolds seem to have little actual benefit in suppressing disease and aboveground insect pests, except perhaps to woo certain insects away from other plants. Be wary of such claims as, "I planted marigolds in my bean patch and did not have any beetles to speak of, while my neighbor's bean plants were devoured by Mexican bean beetles." Was this gardener growing the same bean variety as the neighbor? Were soil conditions the same? Did he or she perhaps forget about the insecticide also applied? It happens. Below ground, marigolds do have some benefit — on nematodes, at least. However, you have to plant masses of marigolds to get this benefit and anyway, not every garden has nematode problems.
Related Stories
ABC News Live