Nemesia Flower Care: Learn Nemesia Plants Growing Requirements

Nemesia is a genus of annuals and perennials native to the sandy regions of South Africa, but the most widely cultivated varieties are annuals.

Pronounced [ne-MEE-see-uh], the name comes from the Greek Goddess of justice, Nemesis.

The Nemesia flower is interesting.

They bloom late in the summer but provide a second bloom in the fall when cutting back after the first bloom.

flowering Nemesa in a window box

In mild climates such as Florida or California, these plants provide a winter bloom.

As with most summer annuals, Nemesias are easy to grow whether planted out in the garden, in a window box or a railing planter.

Nemesia Flower Care

Size and Growth

In USDA hardiness zones 9 and 10, Nemesia plants are grown as a perennial.

Outside of the warmer regions, it’s an annual.

Nemesias are bushy plants, producing growth reaching up to 12” to 24” inches tall.

Most varieties grow upright while others produce trailing stems.

Commonly used for edging plants, ground covers, and borders, these plants have thin stems and light, airy foliage.

These plants grow quickly throughout the first part of the year. In late fall, they start to wither.

Nemesia Flowers and Fragrance

The flowers vary depending on the species with most Nemesia varieties producing small one-inch flowers on 12” inch stems.

Nemesias are available in a wide range of colors, including:

  • Yellow
  • White
  • Orange
  • Red
  • Pink
  • Violet

Most seed packets include a variety of colors.

There are also hybrids with larger flowers or compact growth.

These plants are late bloomers with most varieties producing flowers in late June.

The flowers don’t have a noticeable fragrance.

To get a second bloom, remember to cut the plants back after the first bloom.

Light and Temperature

Most varieties of Nemesia prefer sunny conditions but not full sun.

Whether grown behind glass or outdoors, protect against direct afternoon sunlight.

While the plants can’t always tolerate direct sunlight, avoid areas that are too shaded as well.

Without enough sunlight, the plants will not produce as many flowers.

Some varieties of Nemesia grow as perennials in warmer climates but not climates that are too hot and humid during the summer.

These plants prefer moderate temperatures during the day and cooler temperatures at night, which also encourages fuller blooms.

Watering and Feeding

These plants grow best in slightly dry conditions.

They can even thrive in poor soil with minimal nutrients.

Water the plants moderately, whether grown in the garden or a pot.

Keep the soil moist except immediately after transplanting seedlings.

Soil and Transplanting

Only seedlings need transplanting.

When the seedlings are still young, repot them in their final homes using potting soil with good drainage.

Sow the seeds indoors in March for summer bloom.

Place the seedlings in a bright windowsill but try to keep the temperature at about 55° to 60° degrees Fahrenheit.

The seedlings typically take about two to three weeks to germinate.

After germination, move the plants to a room with lower temperatures, such as 50° degrees Fahrenheit.

By the middle of May, the seedlings should be ready for transplanting.

When transplanting the seedlings into a garden, space them about four to six inches apart.

Try to minimize disrupting the roots during transplanting.

Give the newly transplanted Nemesia a proper watering and then allow the soil to mostly dry out before watering again.

TIP: To encourage bushier growth instead of tall upright stems, make sure young plants remain in a room with good air circulation.

Grooming and Maintenance

Groom the plants to produce a second bloom.

Wait until the flowers from the first bloom die off and then cut the plant back, trimming each shoot about halfway.

If the second bloom doesn’t come, the plant may need more nutritious soil.

After cutting back the stems, apply a liquid water soluble fertilizer once.

When plants fail to bloom in the spring, cutting the shoots back by about one-third may help bring the flowers back.

How to Propagate Nemesia

The only way to propagate Nemesia is with seed.

Sow the seeds in spring for the usual late summer bloom.

Nemesia Plant Pests or Diseases

As with many annuals, pests and diseases rarely affect the Nemesia, but there are a few issues that may occur.

If the flowers turn brown or develop spots, the plant may be getting too much water. As mentioned, these plants don’t need frequent watering.

If planted outdoors, protect against severe rain with a plant cover.

When growing from seed, if the seedlings fall over or turn brown, the young plants may be suffering from a fungal disease. Unfortunately, there is no saving the seedlings.

To prevent the same issue from occurring, try sowing the seeds in a brighter location or provide better ventilation.

Ideas On Use and Where To Grow Nemesia

The beautiful summer and fall flowers grow well in flower pots, gardens, balconies, and make attractive window box flowers.

They are also frequently used for ground cover and garden bedding, especially the shorter varieties.