Nemesia Plant Profile

How to plant and care for nemesias

nemesia up close

 

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The Nemesia plant may resemble an orchid, but it’s actually a small bedding plant that has an array of implications for any garden. Often incorporated into landscaping as edging plants or ground covers—as well as in mixed borders, woodland plantings, rock gardens, and hanging basket plants—the Nemesia is a vibrant and maintenance flower.

The two most popular species are N. strumosa and N. caerulea. Most varieties of Nemesia can grow to about a foot in height, but some can be as tall as two feet. The versatile plants also come in a wide range of colors, and some are even bi-colored. The N. strumosa variety is a true annual that produces one-inch blue or white flowers and grows up to a foot tall, while N. caerulea is a more tender perennial that grows up to about a half-inch and blooms in purple, pink, blue, and white on plants that grow up to two feet.

At a distance, these plants may also look like tiny snapdragons or edging lobelia, with flowers that can completely cover low-growing foliage (the top four petals form a fan with one large and sometimes lobed petal underneath). As long as temperatures remain mild, the plant can produce so many flowers that they almost entirely obscure any other foliage.

Botanical Name Scrophulariaceae
Common Name Nemesia
Plant Type Annual
Mature Size 10-24 inches
Sun Exposure Part to full sun
Soil Type Rich soil, sandy
Soil pH 5.5-7.5
Bloom Time Spring and Summer
Flower Color White, red, pink, blue, orange
Hardiness Zones 2-10
Native Area Africa

How to Grow Nemesia Plants

It’s usually a good idea to plant your nemesias indoors first, especially if you live in a warmer climate. You should start the process about seven or eight weeks before the last frost of spring. Provided your soil temperatures are between 55 and 65 degrees Fahrenheit, you can expect the seeds to sprout in about five to 10 days.

When it comes to nemesias, older seedlings often don’t transplant very well, so when choosing plants, opt for one that has a lot of buds but only a few open flowers (as this will ease the transplanting stress). If you do start with your own seeds indoors, be sure to plant them in peat pots filled with vermiculite. When the seedlings are about two inches tall, try pinching out the growth tips to encourage a bushy growth habit. The Nemesia can be transplanted into the garden—keeping them about four to six inches apart—but only when all danger of frost has passed. Plant your nemesias in a partially-shaded area of the garden with rich, moist soil and adequate drainage.

You’ll want to be careful to disturb the roots as little as possible—and water deeply—after transplanting. A layer of organic mulch should be added to help insulate the roots from any temperature extremes as well as help the soil retain moisture. Once your nemesias are established in the garden, the plants actually won’t need much care aside from watering to help keep the soil moist. If your plants do stop blooming, try cutting them back by about one-third in order to help bring them back into bloom.

Light

The nemesia plant will grow best in full sunlight, however these plants may bloom longer (particularly in warmer climates) if they do happen to get some afternoon shade.

Soil

Nemesias require a planting area with soil that's moist but well-drained, as well as rich in organic matter.

Water

An abundance of water will lead to stem rot on a nemesia plant. While it's important to keep the soil moist for these particular flowers, be wary of over-watering.

Temperature and Humidity

Nemesia will grow best in cooler temperatures. In areas that have more mild summer temperatures, they can be expected to bloom from late spring until the first frost of the year, while in hotter climates they will look their best in early spring or fall. Be prepared for your nemesias to die back in the heat of summer. These plants can be grown as winter annuals in frost-free regions.

Fertilizer

Be sure to fertilize your mature nemesias using a a slow-release fertilizer. Apply the fertilizer once in the spring, or you can also choose a water-soluble fertilizer that can be applied twice monthly as they are actively growing.

Potting and Repotting

If you’d like to grow nemesias in a pot for your home, you’ll need to use a high-quality potting soil (that’s slightly acidic) mixed with a little sand, perlite, or vermiculite to encourage proper drainage. If opting for garden soil, add compost and check the pH to ensure acidity. 

Propagating Nemesia

The nemesia is a fairly easy plant to propagate. It will reproduce much like any other flowering plant—if you let it set seeds, it will propagate on its own. If you’re attempting to intentionally propagate the nemesia plant, you can do so by sowing seeds or by taking cuttings.

Varieties of Nemesia

  • Blueberry Ripple – Deep purple
  • Strawberry Ripple – Strawberry pink to red
  • Berries and Cream – Blue and white

Pruning

You'll want to cut wilted flowers off your nemesias right away, which will help stimulate the plant to produce new flowers. Once the plant has fully bloomed and the leaves have withered away, cut them back as short as you can.

Growing in Containers

The nemesia is a flower that's perfectly suited to growing in pots for use in garden boxes; all you'll have to do it opt for a proper flower plant soil mix, ensure the bottom of the pot has a hole in it, and water when the surface of the substrate has dried up.