Hello sunshine! That’s the cheerful greeting from marigolds, and what better tonic is there than a bed, border or container filled with marigolds.
Marigolds are fuss-free, quick-growing, and cope with the heat even during the hottest time of the year. They are relatively drought tolerant, needing regular but not excessive watering. The flowers are edible, the leaves can be used in insect-repelling sprays and the roots produce a substance (alpha-terphenyl) that suppresses the growth of plant-parasitic nematodes and other organisms such as fungi, bacteria, insects, and some viruses. A good, all-round garden citizen.
There are two types of marigolds, and each has their charm and use in the garden.
African marigolds (Tagetes erecta) have large double flower heads that are ball shaped. Most varieties are 30 – 40cm high, carrying the round heads above dark green leaves on sturdy, compact plants that always look lush and healthy. In addition to yellow, gold and orange there is a creamy-white variety called ‘Vanilla’. They are best used as a bedding and landscape plant, massed in front of taller perennials like salvia, pentas, ornamental millets, grasses and shrubs.
French marigolds (Tagetes patula) have a variety of flower shapes; anemone, frilly doubles and crested doubles. The anemone type is the showiest, with a wide range of colours, the prettiest being mahogany edged with yellow or golden yellow tipped with red. The double crested varieties have larger frilly flowers that come closest to the pom pom shape. Novelties are ‘Fireball’ and ‘Strawberry Blonde’ that produce multicolour blooms on the same plant. Most French marigolds grow 25cm high and wide but there are very compact dwarf varieties that stay 15cm high and wide and are very heat tolerant.
French marigolds are good edging and border plants for smaller spaces and can be used en masse as bedding plants. They combine well with Angelonia, alyssum, bedding salvia, Felicia, petunias and vinca. They are durable, rewarding container plants that don’t overwhelm other plants in a mixed container.
- Plant in full sun, in soil that drains well. Marigolds grow in any type of garden soil. Enrich with compost before planting.
- Water deeply once or twice a week in summer, depending on the soil. Shallow watering encourages the roots to stay near the surface which makes plants less drought tolerant.
- Space plants 15 to 20cm apart so that the leaves can dry out after watering or rain. Leaves that stay wet become susceptible to fungus disease.
- During hot and dry conditions, watch out for pests and water more regularly because marigolds are susceptible to pests and diseases when suffering from extreme heat stress.
- Dead head African marigolds to encourage quicker repeat flowering. Fertilise with a high potassium fertiliser like 3:1: 5 or 5:1:5 after cutting back to give plants a boost.