The Nemesia genus contains more than 50 species, most of which are native to South Africa, but only a few are popular garden plants named cultivars. The two most popular species are N. strumosa and N. caerulea.
N. strumosa is a true annual that produces one-inch blue or white flowers and grows up to one foot tall. N. caerulea is a tender perennial that produces one-half-inch blossoms in purple, pink, blue, and white on plants that grow up to two feet. Even more common as garden plants are the hybrid forms derived by crossing various Nemesia species.
Nemesia plants feature lance-shaped leaves that appear in pairs along the stems, and the flowers bear a similarity to snapdragons, with a two-lipped, tubular shape. As long as temperatures remain mild, the plant can produce so many flowers that they almost entirely obscure the foliage from spring into fall. Usually planted as a garden-ready nursery plant in spring, its also easy to grow from seed. Gardeners in cold-winter climates can seed directly into the garden for summer blooms or start them indoors for earlier flowering. Gardeners in warm-winter climates often seed directly into the garden in fall for winter bloom.
Nemesia is a charming annual flower that adds vibrant color to gardens containers and hanging baskets with its delicate blooms. But this South African native can sometimes take a turn for the worse, leaving gardeners scratching their heads wondering why their once vibrant nemesia is now dying.
Don’t give up hope! With a little detective work and some adjustments to care, it’s often possible to diagnose the cause of nemesia problems and nurse your plants back to health Here are the most common reasons nemesia starts to decline, along with solutions to revive your flowers
Overview of Nemesia Characteristics
Before diving into troubleshooting, let’s overview some key facts about nemesia that impact its care
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Native to South Africa, nemesia thrives in cool climates.
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Most varieties grow 6-12 inches tall and spread 1-2 feet wide. Trailing types work well in hanging pots.
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Flowers resemble small snapdragons in white, pink, purple, yellow, orange or bicolor. Very prolific bloomers.
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Requires full sun and moderately moist, well-draining soil.
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Usually grown as annuals in zones 3-9, but may perennialize in zones 9-10.
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Can rebound after summer heat by cutting back spent growth.
Top 6 Reasons Nemesia is Dying
If your once vibrant nemesia starts looking lackluster with wilting, spotty leaves and struggling blooms, review these common causes:
1. Improper Watering
Too much or too little water can stress plants. Nemesia needs consistently moist soil but hates soggy roots. Overwatering leads to fungal issues while underwatering causes wilting.
Solution: Water thoroughly only when the top inch of soil is dry. Improve drainage in heavy soils.
2. Extreme Temperatures
Temperature extremes damage nemesia. Hot sun over 75°F burns foliage and flowers causing dieback. Frost below 30°F kills the plant.
Solution: Move pots to shade during hot afternoons. Bring containers indoors if frost threatens.
3. Lack of Sunlight
Insufficient sunlight leads to weak, leggy growth with few blooms. Nemesia thrives in full sun – at least 6 hours of direct light daily.
Solution: Find a new spot with maximum sunlight, especially important in spring and fall when light levels are lower.
4. Nutrient Deficiencies
Yellowing leaves often indicate a nitrogen deficiency. Without proper nutrition, plants become stressed and decline.
Solution: Fertilize every 2-3 weeks with a balanced soluble plant food during the growing season.
5. Pests
Spider mites, thrips, slugs and other pests damage plants. Watch for chewed leaves, sticky residue or visible insects.
Solution: Remove pests by hand or use organic insecticidal soap. Improve conditions to deter future attacks.
6. Disease
Several fungal issues plague nemesia like botrytis, powdery mildew, and root rot. These quickly spread to infect the whole plant.
Solution: Improve air circulation. Avoid wetting foliage. Remove and destroy diseased plants to prevent spreading spores.
How to Revive a Dying Nemesia Plant
If your nemesia starts declining, take prompt action to nurse it back to health:
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Assess soil moisture and water thoroughly if dry. Drowning roots is worse than underwatering, so allow soil to partially dry before next watering.
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Move pot to a shady spot out of intense afternoon sun, especially if over 85°F.
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Apply a general purpose fertilizer according to label directions. Repeat every 2-3 weeks.
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Inspect closely for pests and treat accordingly. Isolate affected plants to avoid spread.
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Prune off any dead, diseased or damaged growth. Disinfect pruners between cuts.
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Transplant into fresh soil or repot if the original soil is dense, depleted or waterlogged.
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Cut back severely distressed plants by 1/3 to encourage fresh regrowth.
How to Prevent Future Nemesia Problems
While nemesia issues can often be remedied, prevention is the best approach. Here are proactive care tips:
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Select disease-resistant varieties better suited for your growing zone.
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Plant in porous potting mix and containers with drainage holes.
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Water at the soil level rather than overhead to deter fungal disease.
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Space plants appropriately to allow air circulation.
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Apply mulch to insulate roots and maintain even soil moisture and temperature.
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Stake or cage tall varieties to prevent damage from wind and rain.
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Monitor closely and treat pests before they become severe.
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Avoid overhead watering and prune off infected parts immediately to control disease.
Enjoy Nemesia’s Delicate Beauty
With the right growing conditions and attentive care, it’s possible to avoid many common nemesia plant problems. A bit of TLC can nurse struggling plants back to their former vigor. Pay attention to your plant’s needs and make adjustments as issues arise. Then you can sit back and revel in the delicate beauty of nemesia blooms all season long.
What’s Wrong with My Nemesia?
Problems with nemesia may include the following:
Powdery Mildew: A white powdery substance on leaves and stems is often fungal mold, also called powdery mildew. This starts in spring when conditions are still damp and humid, but temps have warmed. It will spread among the nemesias, but likely won’t affect other nearby plants. Avoid this fungus by watering plants at the roots, as overhead watering encourages spread and development.
Aphids: If you see a swarm of tiny black bugs around new growth when you’re nemesia troubleshooting, it is likely aphids. Blast them off with the water hose, trying to avoid wetting foliage unnecessarily. If they return, spray with an insecticidal soap or neem oil when the sun is not shining on the plants.
Western Flower Thrips: Tan scars on foliage and white scars on flowers are an indication of this pest. Look for a light brown pest with clear wings. Treat thrips with insecticidal soap before moving on to insecticide if soap spray is unsuccessful.
Insufficient Fertilization: Yellowing of lower leaves are sometimes the result of nitrogen deficiency. Use a balanced fertilizer to provide nitrogen when signs appear. Phosphorous is needed for a healthy root system and longer lasting blooms. A lack of this nutrient may appear as purple coloring in the leaves and non-flowering. Remove damaged leaves in both cases.
Nemesia Care
When buying nursery starts, look for seedlings that have lots of buds but only a few open flowers. Nemesia doesnt transplant well, so choosing plants that are not yet flowering will reduce stress. If growing from seed, start them seven or eight weeks before the last expected frost date.
Seedlings or potted nursery starts should be planted into the garden when all danger of frost has passed, spaced four to six inches apart. Choose a partially shaded area of the garden with rich, moist soil and adequate drainage. A layer of organic mulch will help insulate the roots from any temperature extremes as well as help the soil retain moisture. Once your nemesia plants are established in the garden, the plants actually won’t need much care aside from watering to help keep the soil moist.
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Revive your dried /underwatered plant
FAQ
How often do you water Nemesia?
Nemesia (Nemesia spp.) is a group of flowering annuals that needs routine watering to thrive. Keep the soil consistently moist to help the plant form a robust root system. This flowering beauty likes damp conditions, but too much water can cause root rot. Water Nemesia when the top few inches of the soil are dry.
Does Nemesia like full sun or shade?
1. Provide adequate sunlight. Nemesia plants will grow best in full sun, although they will tolerate a few hours of part shade or partial shade.
Does Nemesia need to be deadheaded?
Nemesia responds well to deadheading or removing spent flowers. Pinch back blooms as soon as they start to fade or show signs of dying.
Is Nemesia heat tolerant?
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, dying back somewhat during the heat of summer.
Are Nemesia problems serious?
While nemesia plant problems aren’t usually serious, this long period of growth provides more opportunity for disease to develop and pests to attack. These are common nemesia issues for which to keep an eye out. Learn how to spot them in early development so they don’t mar your beautiful flowering plants. What’s Wrong with My Nemesia?
What is dysmetria and what are its causes?
Dysmetria is a neurological disorder that causes a loss of coordination, causing a person to overreach or underreach their desired goal. It is frequently connected with issues in the cerebellum, the portion of the brain responsible for coordinating movement and motor functions. Various conditions, including neurological illnesses such as multiple sclerosis, stroke, or cerebellar degeneration, can cause dysmetria. Head trauma, certain drugs, or alcoholism can also cause it. The treatment usually focuses on the underlying reason. It may include physical therapy or rehabilitation to enhance coordination and motor skills.
Why does my Nemesia not bloom?
In warm-weather regions, nemesia may respond well to being offered some shade during the heat of the day. In cooler zones, however, a lack of flowers may mean the plant is getting too little sun. If your plants do stop blooming, try cutting them back by about one-third to help bring them back into bloom.
Why are my Nemesia leaves turning black?
Bacterial Leaf Spot: Another problem caused by using overhead irrigation, greasy black spots start on lower leaves and move up the plant. Water at the roots to avoid this issue. In most cases, nemesia plants are problem free and need only watering, afternoon shade in hot areas, and an overall pruning when blossoms fail.
Should Nemesia be cut back?
Trailing varieties of nemesia are especially prone to developing long, straggly stems without many flowers, especially if they are growing in a less-than-full-sun location. Radically cutting back the stems will prompt the plant to become more bushy and full. This treatment is especially useful for container plants and hanging baskets.
Can Nemesia grow from seed?
Nemesia doesn’t transplant well, so choosing plants that are not yet flowering will reduce stress. If growing from seed, start them seven or eight weeks before the last expected frost date. Seedlings or potted nursery starts should be planted into the garden when all danger of frost has passed, spaced four to six inches apart.