How to Grow and Care for African Marigold (Mexican Marigold)

Taller and more upright than the shorter French marigold, the African marigold (Tagetes erecta)can mature to the grand height of three to four feet. A true annual that lasts only one season, the African marigold is a member of the aster family, with cultivars that offer large round flowers in shades of yellow, orange, and creamy white atop green stems and fern-like foliage.

These aromatic flowers brighten gardens from early summer until frost. While bountiful, these marigolds are not aggressive or invasive. Although native to Mexico and Central America, this plant is usually known as the African marigold because it was through African ports that plant traders first brought the plant to Europe.

Plant seeds or seedlings in the spring after the danger of frost has passed to enjoy a bounty of blooms in just two months. Be aware that the flowers and sap of African marigold are mildly toxic to humans.

African Marigold Care

Tagetes erecta is a good choice for hot, dry garden conditions where French marigolds might struggle. They actually do better in somewhat poor soil, as extremely rich soil encourages lots of green growth at the expense of flowers. African marigolds are extremely easy to grow, making them favorites among many novice gardeners and a good first plant for children to grow. To welcome Tagetes erecta to your garden, purchase plants in spring or grow them from seed.

First, remove any weeds and grass from the site. Till the soil to about six inches deep. Space plants 12 to 16 inches apart or plant in a large container. These are quite tall plants that can flop over, so it's common to pick off the bottom foliage and plant them deep, burying the nodes where leaves were removed to create an extra sturdy root system. Even so, taller varieties will probably need to be staked for extra support, especially if grown in an exposed, windy location.

Light

These annuals will tolerate partial shade but perform their best in full sun. Shady conditions can make the plants very leggy and more prone to toppling over.

Soil

African marigolds are adaptable to many kinds of soil and are known to perform well in poor soil. For best results, new plants require well-draining and fertile soil. Moist sand or loam is ideal, though it's possible to grow African marigolds in both dense clay and dry, gravelly soil.

In poor soils, add compost or other organic, nutrient-rich materials at planting time. Maintain a soil pH of 6.0 to 7.5. African marigolds dislike very acidic soil, and anything below 5.8 is likely to cause poor performance.

Water

Water your African marigolds regularly—the standard one inch per week guideline works well for these plants. Do not overwater them because if the soil isn't well drained, the plants are at risk of drowning or developing root rot. It's fine for soil to dry out completely between watering. African marigolds tolerate dry conditions much better than French marigolds.

Temperature and Humidity

African marigolds prefer hot, dry conditions; they are heat and drought-tolerant, blooming from summer until frost. Cool, damp conditions can encourage fungal diseases and root rot. African marigolds rarely survive beyond the first light frost, and as temperatures dip below 40 degrees Fahrenheit, the end is near.

Fertilizer

African marigolds generally do not need much, if any, fertilizer if they are growing in reasonably good soil. In very poor soils, they can benefit from blending in some slow-release fertilizer at planting time or with a few feedings of a diluted liquid fertilizer over the course of the growing season. For the amount to use, follow the product label instructions. A formulation relatively low in nitrogen, such as 5-10-5, is best.

Types of African Marigold

Many named cultivars of African marigolds are available, thanks to horticulturalists constantly seeking to create plants with blooms that are larger, with different colors, or different shapes. Dozens of named cultivars are currently on the market with more introduced each year. A few of the more popular cultivars are:

• 'Jubilee' features bright, bold yellow ball-shaped blooms adding delicate texture to a garden
• 'Gold Coin' offers showy, fragrant double blooms in gold, orange, and yellow
• 'Safari Tangerine' has large flat-topped blooms in maroon, yellow, andorange
• 'Inca Primrose' offers huge rounded blooms adding height to beds and containers
• 'Antigua Orange' offers mounds of small blooms in gold, orange, and yellow
• 'Crush' brings a summer glow of tidy yellow blooms, perfect for pots
• 'Aurora Gold' produces single or double flowers in shades of orange, yellow, brown, and red
• 'Double Eagle' has large, fully double orange blooms
• 'Sweet Cream' offers bold and creamy white ball-shaped blooms with a hint of buttery yellow
• 'Discovery Series' features adorable dwarfed bushy compact blooms that look beautiful in a fresh-cut arrangement
• 'Taishan® Gold' has bold ball-shaped gold blooms with buttery yellow centers

The African marigold (also known as Mexican marigold and American marigold) is just one species among many in the Tagetes genus. For example, this flower shouldn't be confused with Tagetes lemmonii. Generally known as Lemmon's Marigold, it is also sometimes referred to by the common name Mexican marigold.

Tagetes patula and its many cultivars are commonly known as the French marigolds. They are generally shorter than African marigolds, with a spreading habit and smaller flowers.

Tagetes tenuifoli (known as signet marigolds) is another large group. These, too, are smaller plants with smaller flowers, and they are much more likely to survive mild frosts.

Pruning

Left alone, African marigolds tend to shoot upward and can become top-heavy, so it's common to pinch back the tips when the plants are young to encourage side branching and denser growth.

Deadhead plants regularly to encourage a longer period of flower growth and to prevent flopping. When deadheading, it's best to clip off the flower stalks down to the next set of leaves. At the end of the season, simply yank the plants from the ground and discard them (or add them to a compost pile).

Propagating African Marigold

African marigold grows so readily from commercial seed that vegetative propagation is rarely done—it can take longer to propagate cuttings than for seeds to sprout and mature. But if you don't want to buy new seeds, asexual reproduction by rooting stem cuttings is a way to ensure that you achieve exact duplicates from hybrid varieties growing in your garden. (Seeds collected from flower heads will easily grow, but their genetics can be somewhat different than hybrid parent plants.)

Here's how to propagate from stem cuttings:

1. Using sharp pruners, clip off four-inch segments from the tips of healthy stems, preferably without flowers or buds.
2. Remove any remaining flowers and buds as well as the lower leaves on the cutting.
3. Moisten the potting mix.
4. Plant the cutting in a small pot filled with commercial potting mix.
5. Enclose the planted cutting in a plastic bag, and place it in a bright, warm location, but not in direct sunlight.
6. Periodically check the cutting to see if roots are forming, and to moisten the potting mix as needed.
7. When you feel resistance when gently tugging on the stem, it means the cutting has rooted. At this point, you can remove the plastic bag and continue growing the plant in full sunlight. It can be planted in the garden at any time during the growing season.

How to Grow African Marigold From Seed

Marigold seeds can be collected from spent flowers to sow the following spring, but because most nursery marigolds are hybrids, the seeds they produce may not come true if planted. Thus, growing marigolds from seed is best done with purchased seeds, which are bred under controlled nursery conditions for precise genetic heritage.

If you are not concerned about the perfect duplication of garden plants, then it's certainly possible (and quite easy) to harvest seeds by simply breaking apart some dried flower heads. The elongated black seeds inside can be planted and will certainly produce flowering plants, though possibly with a different look than the parent plants.

Sow seeds indoors in small pots or seed trays filled with commercial potting mix four to six weeks before the average last frost date. Place them in an area where temperatures remain between 70 and 75 degrees Fahrenheit and watch seedlings emerge four to 14 days later.

You can also sow the seeds directly in the garden when the danger of frost has passed. These are relatively fast-growing plants that will bloom in about two months when planted from seed.

Potting and Repotting African Marigold

Marigolds are easily grown in containers filled with standard commercial potting mix. It's a good idea to blend in some granular fertilizer, or to use a potting mix with fertilizer already added. African marigolds get quite large, so use a large container, at least ten inches in diameter, and deep enough to allow for staking, if needed. Pots can be made of any material—plastic, wood, clay, or ceramic— but heavier materials will help prevent these tall plants from tipping in the wind.

Repotting won't be necessary because these annuals die at the end of the growing season.

Common Pests & Plant Diseases

While African marigolds are not usually prone to pest damage, keep an eye out for Japanese beetles, red spider mites, slugs, and snails. Use insecticidal soap as needed.

Overwatering and wetting the foliage late in the day can lead to fungal infections. African marigolds are susceptible to powdery mildew, botrytis, and various leaf spot and root rots. Plants are best watered through ground-level soaking early in the day. Chemical fungicides can be used, but it's best to simply remove affected plant parts and make sure plants are watered correctly and have good air circulation, which will prevent most fungal diseases.

How to Get African Marigolds to Bloom

African marigolds typically bloom from early summer into late fall, and failure to bloom is rare and usually traced to simple explanations:

• Not enough sun. For robust, repeated blooming, make sure African marigolds get plenty of sun—at least six to eight hours per day. Shady conditions make for leggy plants and fewer blossoms.
• Too much fertilizer. African marigolds thrive on relatively meager soils and fertilizing too much causes lots of green foliage but fewer flowers.

Common Problems with African Marigolds

Aside from relatively rare problems with fungal diseases and root rot, African marigolds seldom give gardeners cause for complaint. The most common problem is that they are prone to toppling over because the large flowers make the plant top-heavy. You can counter this by pinching back the plants when they are young to make them branch out, by quickly deadheading the spent flowers, and by staking if necessary. It also helps to plant them unusually deep to ensure a robust, strong root system.

From: thespruce