Years ago, my friend Lois shared a tip for growing marigolds that is one of the best gardening tips I have ever received. It goes like this: In late spring, after the soil has warmed, sow a cheap packet of marigold seeds in a small nursery bed that is convenient to weed and water. When the marigold seedlings grow to 4 inches (10 cm) high, dig and move them to places where you want bold fall colour similar to what you might get with chrysanthemums. Because of their late start, the marigolds hold their fire until summer's end, then cover themselves with blossoms for two months, or until the first hard freeze takes them down. Handled this way, marigolds make chrysanthemums look lazy.
Types of Marigolds
Marigolds have tropical or semi-tropical origins in the Americas, which explains their need for warm growing conditions. Marigold species vary in size and in the other talents they bring to the garden, but all make phenomenal colour plants for fall.
Large-flowered marigolds (Tagetes erecta) are stiffly upright plants that grow to about 24 inches (60 cm) tall, and produce big, ruffled flowers in shades of yellow and orange. Sometimes called African or American marigolds, these heavy bloomers can appear somewhat clunky in the summer garden, but in the fall the burning balls of colour are a visual treat.
Speaking of vision, deep orange marigold petals are an excellent source of lutein and zeaxanthin, two phytochemicals associated with eye health. Many natural lutein dietary supplements are based on extracts from marigold petals, which retain their lutein and lycopene when dried. You can consume dried marigold petals directly, by adding the flakes to smoothies or teas, or by feeding them to your chickens and then eating the eggs.
French marigolds (Tagetes patula) are smaller in all ways compared to their larger cousins. Growing into rounded bushes about 18 inches (45 cm) tall, French marigolds are thought to be an interspecies hybrid between large-flowered marigolds and signet marigolds (see below). The foliage of French marigolds releases a musky fragrance when crushed, like that of large-flowered marigolds.
French marigolds are heavily used in commercial landscapes because they deliver such great low-maintenance colour, but gardeners have other reasons for growing these bomb-poof flowers. Most marigolds inhibit soil-borne rootknot nematodes, but French marigolds are especially talented at luring nematodes to their death. In warm climates with sandy soil where nematodes are a constant concern, cover cropping with French marigolds can be a valuable management tool.
Signet Marigolds (Tagetes tenuifolia) are airy, winsome plants compared to other marigolds. The thin stems are prone to falling into a cascade, which is eventually covered with hundreds of petite yellow, orange, or mahogany flowers.
When crushed, the foliage of signet marigolds gives off a citrusy fragrance, and the petals have a sweet floral flavour when chopped into salads. By far the best marigold for containers, little signets are often known as gem marigolds due to the sustained popularity of the 'Lemon Gem' and 'Orange Gem' varieties. Bicoloured 'Starfire' and dark red-orange 'Paprika' are equally good, and it's easy to save and replant seeds from plants you especially like.
In Mexico, marigold blossoms are used to decorate graves, but in India the pure orange and yellow shades of marigold (gendu) blossoms have earned them important places in religious and cultural ceremonies. Marigolds are by far the most widely grown flower in India, but the marigolds in my autumn garden need no special meaning. It is enough that they provide flawless colour in the waning days of fall.
By Barbara Pleasant