HARDINESS: Frost tolerant
PREFERRED SOIL pH: Neutral to slightly acidic
PREFERRED SOIL TYPE: Fertile, well-drained
PREFERRED LIGHT: Sun
ATTRIBUTES: Daisy-shaped flowers in bright shades of yellow or orange; use dwarf varieties in containers and window boxes; grow long-stemmed varieties in beds
SEASONS OF INTEREST: Summer to fall
FAVORITES: 'Lemon Cream' for color; 'Prince' series for cutting; compact Bon Bon Mix, 'Calypso' for containers
QUIRKS: May slop blooming in very hot weather
GOOD NEIGHBORS: Ageratum, borage, dusty miller, forget-me-not, bachelor's button, larkspur, nasturtium
WHERE IT GROWS BEST: Fertile, well-drained, sunny sites; cool climate
POTENTIAL PROBLEMS: Powdery mildew, cabbage loopers
CRITTER RESISTANCE: Good
SOURCE: Bedding plants, seeds
DIMENSIONS: 8-30 in (20.3-76.2 cm) tall and 12-18 in (305-45 7 cm) wide
Calendula in the Landscape
Affectionately known as pot marigolds, calendulas radiate cheerful, bold, yellow or orange flowers above fresh green foliage. Taller varieties are at home in informal borders, whereas the shorter ones work well in containers and along the fronts of beds. In regions where summer is cool, calendulas bloom reliably from early summer to fall. But because they don't grow or flower well in extreme heat, they are best grown from fall to spring in southern climates.
Calendula flowers look like daisies, with a central disk surrounded by a ray of petals. There are numerous variations on this theme, including forms with single, semi-double, or fully double flowers in colors ranging from bright orange to lemon yellow to creamy parchment. Some varieties have a thin edging of sepia or a touch of pink in their petals. Ranging in height from 12 to 30 in (30.5 to 76.2 cm), the long-stemmed calendulas make great cut flowers.
In beds, weave calendulas among upright-growing blue-flowered plants, such as larkspur, bachelor s button, browallia, and borage, or mix them with the soft purple flowers of anise hyssop. Nasturtiums and other plants with yellow to orange flowers also combine well.
Calendula petals are edible, and their bright color is especially eye-catching when sprinkled over cream sauces, white rice, or potatoes. Calendula petals can be used as an inexpensive substitute for saffron coloring in some dishes, but the petals lack saffron's unique bitter, rangy taste.
New Colors and Sizes
Packets of calendula seeds may include a single color or a mixture of hues. The 'Kablouna' series grows to 24 in (61 cm) tall. The flowers have prominent central disks and short, shaggy petals that make the blossoms resemble strawflowers. Within the series, the 'Lemon Cream' variety is particularly attractive. The flowers have a bright yellow eye surrounded by white petals edged in yellow. The Prince series has double flowers with long stems, making them ideal for cutting. Where compact plants are needed, try the 12 in (30.5 cm) tall Bon Bon Mix or the 8 in (20.3 cm) tall 'Calypso', which is available in either orange or yellow.
You can grow calendulas from seed or start with bedding plants purchased at a garden center. Both prefer cool temperatures, so get an early start. Start seed indoors 6 weeks before your last frost. Sow the seeds on moist potting medium, covering with enough soil to provide darkness. Keep the soil moist and at room temperature until the seedlings have several sets of leaves. Set out seedlings or bedding plants at about the time the last frost passes. Calendulas benefit from a half-strength application of a balanced fertilizer, such as 10-10-10, well mixed into the soil prior to planting. Water as needed to keep the soil barely moist, and surround plants with a 3 in (7.6 cm) thick layer of organic mulch, such as compost or leaf mold, to conserve soil moisture.
Snip off fading flowers regularly to encourage branching and flowering. Late in summer, when days are hot and nights cool, leaves may develop white powdery patches, a symptom of the fungal disease powdery mildew. Clip off disfigured leaves, or dispose of plants that are badly affected. While calendulas are virtually insect free, the leaves and flower buds can be munched, beginning in spring, by small green caterpillars called cabbage loopers, which double up like inch-worms as they move. Spray young loopers with the biological insecticide BT (Bacillus thuringiensis) as directed.