Marigolds

Everyone knows marigolds. Old fashioned, yellow, orange and rust coloured flowers, highly ‘fragrant’, lacy leaves, and prolific self seeders. I say ‘fragrant’ because if you’ve sniffed a marigold you’ll know that they have a very distinct pungent smell that’s not exactly fragrant in terms of a rose! The marigolds we grow in the garden are usually French (Tagetes patula) or African (T. erecta), but a commonly related weed is Stinking Roger (T. minuta) which has tiny flowers but the same boisterous scent. I don’t know who Roger was but I feel a bit sorry for him.

Back to garden marigolds though, despite the common names being African and French, marigolds actually originated in South America. The tall (up to 1m) African marigolds made their way to Europe via Africa, and the French marigolds were the subject of extensive breeding programs in France to enhance their compact bushy nature. African marigolds tend to have bigger flower heads, but a shorter flowering period compared to the French.

One of the most common uses of marigolds (apart from being bright and cheerful ornamentals!) is as a companion plant. Their scent makes them extremely useful in disguising your fruits and veggies from potential predators, but they also exude a natural pesticide chemical (α-therthienyl) from their roots which helps control nematodes and fumigate the soil.

And if you’re wondering what exactly is a nematode… they are also known as roundworms and are one of the most abundant organisms on earth, ranging in size from a few millimetres up to a few metres. Root knot nematodes (which is usually what we plant marigolds for) are tiny little parasitic roundworms that feed on the roots of plants and cause lumps or galls on the roots which affect the plants uptake of nutrients and can eventually cause its demise.

Marigolds love a full sun spot, and once established don’t require a lot of water, just give them a good soak every now and again. Mine are all self seeded and germinate when the conditions are right so will pop up through summer and they are thriving right now. The best part is if you pull off a couple of the dead flower heads and sprinkle them around, you’ll have marigolds for seasons to come!