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How to Grow Nemesia

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Nemesia are summer-blooming annuals and perennials grown for their abundant, brightly colored flowers. Species and Nemesia cultivars can be colored cream, orange, pink, blue, purple, yellow, and white.

There are about 50 species of Nemesia and many cultivars. The flowers are showy, spurred or pouched, two-lipped, and appear either singly or in small racemes. The flowers have four upper lobes, or “petals”, and one or two large flared lower lobes.

Nemesia are South African natives that thrive in cool-summer climates where nighttime temperatures drop below 65°F (18°C).

Nemesia are a colorful additions to beds, borders, and containers.

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Nemesia in summer border

Get to know Nemesia

  • Plant type: Annuals, some species perennials
  • Growing zones and range: Annual in all zones; perennials grow best in Zones 9-11.
  • Hardiness: Tender
  • Height and width: 10 inches (25cm) tall, 12 inches (30cm) wide
  • Foliage: Narrow lance-shaped, serrated, opposite leaves are usually pale green
  • Flowers: Trumpet-shaped flowers; the flowers have an enlarged lower lip and resemble snapdragons
  • Flower colors: White, yellow, red, pink, lavender, blue, and bicolors
  • Bloom time: Summer
  • Uses: Bedding plants, rock garden, hanging baskets, as bulb covers.
  • Common name: Nemesia
  • Botanical name: Nemesia
  • Family name: Scrophulariacea
  • Origin: South Africa

Where to plant Nemesia

  • Plant Nemesia in full sun.
  • Nemesia blooms best in cool weather. In hot climates, plant Nemesia where it gets dappled shade in the afternoon.
  • Grow Nemesia in average to humus-rich, well-drained soil.
  • Nemesia grows and blooms best in regions with mild summers and cool nighttime temperatures.
  • Nemesia prefers a soil pH of 5.5 to 6.5.

Nemesia uses

  • Nemesia is a handsome edging plant.
  • Add Nemesia to a rock garden.
  • Grow Nemesia in containers.
Nemesia strumosa growing in a container
Nemesia strumosa growing in a container

When to plant Nemesia

  • Set Nemesia in the garden after the last frost in spring.
  • Sow seeds indoors 8 to 10 weeks before the last frost in spring; start seed at 55° to 65°F (12.8°-18°C).
  • Sow seed in a sterile seed-starting mix to prevent damping off.

Planting and spacing Nemesia

  • Transplant Nemesia with care as the roots are brittle.
  • Space Nemesia 10 to 12 inches (25-30cm) apart

How to water and feed Nemesia

  • Nemesia wants soil that remains evenly moist.
  • Fertilize Nemesia with an all-purpose fertilizer at planting time.
Yellow orange nemesia flower in the garden.

Nemesia care

  • Deadhead faded blooms to prolong blooms time.
  • Pinch out growing tips to encourage bushy growth.
  • Cut Nemesia back by half after the first flush of bloom. Nemesia blooms best in cool weather.

Nemesia pests and diseases

  • Nemesia is generally not bothered by pests and diseases.
Nemesia in windowbox
Windowbox with nemesia and forget-me-nots flowers

Nemesia propagation

  • Sow seeds indoors in early spring. Sow seed outdoors after the last frost.
  • Germination takes 7 to 14 days at 60° to 68°F (16°-20°C).
  • Take softwood cuttings of perennials in early spring or semi-hardwood cuttings in late summer.

Nemesia varieties to grow

  • Nemesia strumosa: Wild species grows to 18 inches (45cm) tall; plants sold under this name are usually compact hybrids between N. strumosa and N. versicolor; hybrids include all colors except green.
  • N. versicolor: Resembles N. strumosa but colors are blue, yellow, and white; ‘Blue Gen’ cultivar is pure blue.

Nemesia frequently asked questions

Q: How do I grow nemesia from seed?

A: For the best results, start seeds indoors four to six weeks before transplanting seedlings outside. Cover the seeds completely; they need darkness to germinate.

Q: My nemesia grows tall and lanky and does not flower. What is wrong?

A; There are a few reasons: nemesia must have a cool, dry climate to thrive; it does not do well in hot, highly humid regions. Pinch it back at planting time to encourage business. Give it full sun or light state and humus-rich, moist soil that is mulched to keep it cool. Give nemesia plenty of all-purpose organic fertilizer.

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Written by Stephen Albert

Stephen Albert is a horticulturist, master gardener, and certified nurseryman who has taught at the University of California for more than 25 years. He holds graduate degrees from the University of California and the University of Iowa. His books include Vegetable Garden Grower’s Guide, Vegetable Garden Almanac & Planner, Tomato Grower’s Answer Book, and Kitchen Garden Grower’s Guide. His Vegetable Garden Grower’s Masterclass is available online. has more than 10 million visitors each year.

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