Question: My grandmother always had a beautiful array of marigolds in her garden. I would love to add some to our landscape here. Can you give me some tips for growing marigolds?
Answer: Marigolds (Tagetes) are native to Mexico and Central America. Marigolds come in varieties ranging from 6 inches to 4 feet in height. The colors range from bright yellow through orange and red.
Most varieties have strongly scented foliage. Marigolds are easy to grow, making them popular as cut flowers and border plants. They also can be used as container plants.
Marigolds come in four different types. These are:
- American/African marigolds (Tagetes erecta) are the tallest and most upright, reaching three to four feet in height. They thrive under hot, dry conditions. Varieties include Vanilla and Mission Giant.
- French marigolds (T. patula) tend to be dwarf varieties. They are often wider than they are tall. Elegant and eye-catching, they have brilliant red and orange flowers and usually grow from 6 inches to 2 feet tall. They are also slightly aromatic. Varieties include Bonanza and Colossus.
- Triploid marigolds are a hybrid between African and French and are multi-colored. Triploid hybrid marigolds are unable to set seed. As a result, plants bloom repeatedly through the summer, even in hot weather. Since the triploid hybrids are unable to produce viable seed, they also known as mule marigolds. Varieties include Marigold Zenith F1.
- The dainty signet marigolds (T. tenuifolia) like hot, dry sites and make a wonderful edging. They rarely reach more than a foot in height. Varieties include Lemon and Red Gem.
Calendula officinalis, a native of southern Europe, is also commonly called the pot marigold or English marigold, but they are not related to the flowers most people know as marigolds.
Marigolds thrive in full sunshine and can often withstand very hot summers. If planted in the shade or in cool, moist areas, they are prone to powdery mildew and won’t bloom well. Though they grow in almost any soil, marigolds do best in moderately fertile, well-drained soil.
While you can buy marigold plants at your local garden nursery, you can also grow your own marigolds from seed much more cheaply. Sow seeds directly into the garden, once the soil is warm in the spring, one inch apart and no more than ½ inch deep. For earlier blooms, start your seeds indoors in planting trays for later transplanting. Marigolds sprout within days in warm weather and plants bloom in about eight weeks.
Space French and signet types 8-10 inches apart. Larger African varieties should be at least 10-12 inches apart. If planting transplants, thoroughly water each plant after planting in the garden. If planting in containers, use a soil-based potting mix.
Take care to space your plants properly; marigolds grown in containers can become crowded. At time of planting, either mix in a slow-acting granular fertilizer or plan to water with a diluted liquid fertilizer periodically. Water-soluble fertilizer can be given to marigolds once a month, however, do not over-fertilize. A diet that’s too nitrogen-rich stimulates lush foliage at the expense of flowers.
Once the marigolds have established themselves, pinch off the tops of the plants to encourage them to grow bushier. This will keep the plants from becoming leggy and will encourage more blooming.
When you irrigate your marigolds, allow the soil to dry somewhat between waterings, and then water well and repeat the process. Water more in high heat. Do not water your marigolds from overhead sprinklers as the wet foliage will be susceptible to powdery mildew.
If the marigolds are in containers, water them daily as containers tend to dry out quickly. Add a layer of mulch between plants to suppress weeds and keep soil moist.
You can increase the number of blooms and the blooming time by deadheading spent blossoms. Deadheading marigolds is very simple. When a blossom starts to fade, pinch (cut) its stem back to the nearest set of leaves. The plant will be encouraged to produce new flowers. The dense, double flower heads of the African marigolds tend to rot in wet weather, so deadheading is especially important.
Farmers and gardeners have long known that marigolds can be used as companion plants when freely interplanted in the garden with vegetables because of their pest-repellent properties. The underground roots of the French marigold in particular are known to repel damaging nematodes (microscopic worms) that attack the roots of garden vegetables.
Marigolds can be planted throughout the garden among tomatoes, beans, peppers and cucumbers and, anecdotally, have been reported to repel many insect pests.
Marigold wit & wisdom
- In the late 1960s, Burpee president, David Burpee, launched an energetic campaign to have marigolds named the national flower, but in the end, roses won out.
- For years, farmers have included the open-pollinated African marigold “Crackerjack” in chicken feed to make egg yolks a darker yellow.
- Marigolds are one of the October birth flowers.
These easy care plants with their bright blooms are often used as Mother’s Day gifts and growing projects with children. Plan to add some marigold flowers in your own garden this spring and summer.