How to Plant and Grow Nemesia

The annual nemesia was a popular plant in cottage gardens and other old-fashioned settings, but it fell out of use because of its temperamental growth in warm climates. Breeders have created new types capable of growing through the summer and blooming into the fall, especially in mild climates.

Hardy in Zones 9-11, where they can be grown as perennials, nemesia makes a colorful addition to any cool-season garden since they have a wide range of colors. Because they come in almost every color possible (except green), you can easily find a shade for any combination. In addition, many varieties come in bicolor blooms that, up close, are reminiscent of miniature orchids.

Where to Plant Nemesia

Plant nemesia in a location with well-draining, fertile soil in partial shade. Its quick-growing habit also adds to containers and hanging baskets, as it spills nicely down the sides. Plant nemesia near seating areas to enjoy its pleasingly light fragrance.

Nemesia is a lovely addition to the front of a garden bed and can be grown wild as a woodland plant. The shorter varieties are lovely as a groundcover and serve as attractive edging plants. Nemesia also adds a pop of color to rock gardens.

How and When to Plant Nemesia

While nemesia is available ready to plant from most nurseries, you can grow nemesia flowers from seeds. Germinate indoors and transplant them outdoors when temperatures begin to rise in spring in cold weather climates, and in warm climates, transplant them outdoors in the fall. To plant nursery starts, dig a hole about the same width and depth as the planting container. Remove the plant and loosen the roots a bit from the root ball before it placing in the hole. Backfill with soil, tamp lightly, and water well. Plant 4 to 6 inches apart and add mulch to protect from weather extremes.

Nemesia Care Tips

Relatively low-maintenance plants, nemesias are easy to keep happy.

Light

For the best flower production, grow nemesias in full sun. However, giving them a little afternoon shade may extend their blooms a bit longer.

Soil and Water

Make sure they're planted in organically rich, well-drained soils, as anything less is likely to cause the plants to rot. They also appreciate even moisture, so keep your plants watered, especially during the summer heat, if you plan on keeping them through the fall.

Temperature and Humidity

As long as temperatures are mild, nemesia will profusely flower, often obscuring the foliage. However, they tend to go out of flower once night temperatures are consistently above 70 degrees. This is especially true of older varieties, which are particularly sensitive to heat. Nemesia prefers cooler, dry climates over humid ones.

Fertilizer

Feed with a balanced time-release fertilizer once in the spring or apply a water-soluble fertilizer twice a month while they're growing. Also, give nemesia a dose of fertilizer when you cut them back to rejuvenate them. For the amounts to use, follow product label directions.

Pruning

Deadhead right after blooming to stimulate new growth. At the end of the season, pull the plants from the garden if you're growing them as annuals. If you grow them as perennials, cut them back as short as possible for winter.

If the plants begin to go out of bloom during the season, they can become a little rangy. When this happens, give the plants a good shearing to shape them and encourage a fresh wave of new growth and blooms.

Potting and Repotting Nemesia

Nemesia is ideally suited to growing in containers with a light, peat-based potting mix. Use a large container with ample drainage, and water as soon as the soil is dry. Nemesia is best kept as an outdoor potted plant. When grown as an annual, nemesia does not require repotting during the growing season.

Pests and Problems

The main problem nemesia can have is root rot due to overwatering or poor drainage. You'll know when root rot has set in if the stems fall to the ground.

Prevent powdery mildew by giving plants ample space for air circulation and watering at the base of the plant and not from above.

How to Propagate Nemesia

Propagate annual or perennial nemesia by taking 4- to 6-inch stem cuttings from the plant in late summer. Remove the leaves from the bottom half of the cutting and dip it in rooting hormone. Add the cuttings to small pots filled with a soilless planting mix and cover them with clear plastic. Once the plants take root and new growth appears, plant them outside after the last frost of spring. Stem cuttings are the only way to propagate hybrid nemesia plants successfully, but many non-hybrid nemesia varieties can be grown from seed.

Sow nemesia seeds indoors 4 to 6 weeks before the last frost in spring. Fill a container with seed-starting mix and sprinkle the seeds on top. Press the seeds into the mix, making sure they are only lightly covered. Put them in a cool location that receives bright light but not full sun. Keep the soil damp until you see new growth. When the seedlings are big enough, transplant them into individual 3-inch pots. As they grow, pinch them back a couple of times to encourage compact growth.

Types of Nemesia

'Aromatica True Blue' Nemesia

Nemesia 'Aromatica True Blue' bears fragrant soft-blue flowers on 14-inch-tall plants.

'Lemon Mist' Nemesia

Nemesia 'Lemon Mist' is a recent selection with purple and white flowers blotched in yellow. It blooms profusely in spring and fall and grows 7 inches tall and wide.

'Opal Innocence' Nemesia

Nemesia 'Opal Innocence' offers fragrant lavender-gray flowers during the cool seasons of spring and fall. It grows 16 inches tall and 8 inches wide.

'Serengeti Upright Purple' Nemesia

Nemesia 'Serengeti Upright Purple' offers lovely purple flowers. It grows 14 inches tall.

'Safari Violet Rose' Nemesia

Nemesia 'Safari Violet Rose' bears violet-pink flowers on 14-inch-tall plants.

'Serengeti Red' Nemesia

Nemesia 'Serengeti Red' is an especially eye-catching selection with deep-red flowers. It reaches 10 inches tall.

'Serengeti Upright Violet + White' Nemesia

Nemesia 'Serengeti Upright Violet + White' offers lovely violet-purple flowers marked with white. It grows 14 inches tall.

'Serengeti Sunset' Nemesia

Nemesia 'Serengeti Sunset' shows off red flowers streaked in yellow, orange, and pink. It grows 14 inches tall.

'Sunsatia Cranberry' Nemesia

Nemesia 'Sunsatia Cranberry' bears bold red flowers on plants that trail to 36 inches over the side of a container or basket.

'Candy Girl' Nemesia

Nemesia 'Candy Girl' bears soft-pink flowers on compact, 12-inch-tall plants.

Juicy Fruits® Kumquat Nemesia

Nemesia Juicy Fruits® Kumquat features large gold, orange, and cherry red blooms. These lightly fragrant flowers are on heat-tolerant plants that don't require deadheading.

Bluebird Nemesia

Nemesia Bluebird is a wonderful blue variety with hundreds of small blooms. These plants can stand up to summer heat and bloom through the fall.

'Sunsatia Pear' Nemesia

Nemesia Sunsatia Pear is a frost-tolerant selection that bears white flowers marked with orange. It grows 18 inches tall.

Nemesia Companion Plants

Dianthus

The quintessential cottage flower, pinks have grasslike blue-green foliage and abundant starry flowers, which are often spicily fragrant. Depending on the type of pink, flowers appear in spring or summer and tend to be pink, red, white, rose, or lavender, but they come in nearly all shades except true blue. Plants range from tiny creeping groundcovers to 30-inch-tall cut flowers, which are a favorite with florists. Zones 3-10

Snapdragon

Every garden benefits from snapdragons. The blooms come in many colors, including some with color variations on each flower. Plus, snapdragons are an outstanding cut flower. Snapdragons are a cool-season annual, blooming in early spring when warm-season annuals are just being planted. They're also great for fall color. Plant snapdragon in early spring, a few weeks before your region's last frost date. Zones 7-10

Pansy

The genus Viola has a wide array of plants for the spring garden. They don't mind cold weather and can even take a little snow and ice. Pansies are pretty planted in masses in the ground, but they also bring early color to pots, window boxes, and other containers. By summer, pansies bloom less, and their foliage starts to brown. Zones 3-11