Mignonette (Reseda odorata) is one of the most intensely fragrant annuals in the British cottage garden tradition, producing modest racemes of small yellowish-green flowers that fill a room with a warm, sweet, almost grape-like scent. It is not a showy plant in any conventional sense, but generations of gardeners have grown it on windowsills, in pots by doorways, and scattered through borders purely for that extraordinary perfume. When the leaves begin to curl and the soft, pale foliage starts to look ragged, two causes account for the majority of cases: aphid colonies on the shoot tips in spring, and flea beetle damage on seedlings in dry weather. Root rot from waterlogged soil, powdery mildew in dry summers, drought stress, and cucumber mosaic virus are less frequent but worth knowing about.
Quick diagnosis
- Curled, clustered shoot tips with pale green insects in spring: Aphids (Myzus persicae). Blast off with water or apply insecticidal soap.
- Small round shot-holes in leaves, ragged margins, light curling: Flea beetles (Phyllotreta spp.). Cover seedlings with fine mesh netting.
- White powdery coating on curling, distorted leaves in summer: Powdery mildew. Remove affected growth and improve air circulation.
- Yellowing, wilting with wet soil and a rotten smell at the crown: Root rot. Improve drainage; mignonette needs sharp drainage and dislikes heavy clay.
- Leaves rolling in during prolonged dry weather with no pests: Drought stress. Water at the base and mulch around the plant.
- Mosaic mottling, puckering, and distortion alongside curling: Cucumber mosaic virus. Remove affected plants; there is no cure.
Cause 1: Aphids
Aphids are the most common pest of mignonette in UK gardens and the most likely explanation when shoot tips curl downward in spring and early summer. The main species is Myzus persicae, the peach-potato aphid, though several other generalist aphid species also colonise Reseda. Mignonette's soft, pale, watery foliage is particularly attractive to aphids: the leaves offer little physical resistance and contain high levels of the amino acids and sugars that aphids feed on. Spring sowings emerging in March, April, and May are most vulnerable, coinciding with peak aphid dispersal and before natural predator populations have built up to useful numbers.
Colonies are pale green to yellow-green and settle first on the shoot tips and the undersides of the youngest, most tender leaves. The affected leaves curl downward and inward around the colony, and the growing tip takes on a crumpled, bunched appearance as the aphids distort the cells of the developing tissue. Sticky honeydew accumulates on the affected growth and on leaves below the infestation, and if the colony persists a layer of black sooty mould develops on the honeydew. Growth slows noticeably on heavily colonised stems, and if aphid pressure continues unchecked the shoot tip may fail to develop normally.
The good news is that mignonette aphid infestations are self-limiting in a well-managed garden. Ladybirds, hoverfly larvae, lacewings, and parasitic wasps move into gardens rapidly once plants are flowering, and by early summer the predator community usually reduces aphid populations to insignificant levels without intervention. The chief risk is a severe early-season infestation on seedlings before the plants are established.
How to fix it. Blast aphid colonies off with a strong jet of water directed at the curled shoot tips and the undersides of young leaves, and repeat every two to three days until the infestation is cleared. For persistent or severe colonies, apply insecticidal soap or a diluted neem oil spray, ensuring thorough coverage of both leaf surfaces. Avoid systemic or broad-spectrum insecticides: they kill the beneficial insects that will hold future aphid populations in check, and mignonette's pollinators, including hoverflies and bees drawn by the fragrant flowers, are disproportionately vulnerable. Growing mignonette in poor soil without nitrogen-rich fertiliser is the most effective long-term prevention, as it limits the production of soft, sappy growth that aphids find most attractive.
Cause 2: Flea beetles
Flea beetles (Phyllotreta species) are a common problem on mignonette seedlings in UK gardens, particularly in dry springs and early summers. The adult beetles are small (1 to 3 mm), dark, and shiny, with a characteristic jumping escape behaviour when disturbed that gives them their common name. They feed on the leaf surface, chewing small, round to irregular holes typically 1 to 3 mm in diameter. These shot-holes are the most visible sign of flea beetle activity, but the damage extends beyond the holes themselves: the disruption of leaf tissue causes the margins and the areas around the holes to curl and distort, and heavily attacked seedlings can look ragged and misshapen.
Mignonette is in the family Resedaceae, which is related to the brassica family (Brassicaceae), and it appears to be palatable to many of the same flea beetle species that attack cabbages, radishes, and rocket. Damage is most severe on seedlings and young plants in their first few weeks after germination. Established mignonette with a developed root system and multiple stems tolerates light flea beetle feeding without much visible effect on growth or flowering. Dry weather makes the problem worse because flea beetles are most active in warm, dry conditions and because drought-stressed plants lack the vigour to outgrow the damage quickly.
Unlike aphids, flea beetles do not cluster on the plant and are difficult to spot directly. The diagnostic clues are the characteristic shot-holes (round holes punched through the leaf, distinguishable from caterpillar feeding, which produces more irregular edges and larger areas of missing tissue) combined with the jumping behaviour of the adults when the plant is disturbed.
How to fix it. The most effective protection for mignonette seedlings is fine insect mesh netting (1.25 mm aperture or smaller) placed immediately after sowing and kept in place until the plants are well established. The netting excludes adult beetles from the young plants during their most vulnerable period. Because mignonette dislikes root disturbance and is always direct-sown where it is to grow, the netting can be laid flat over the soil surface after sowing and pegged down at the edges. Keep the soil consistently moist during germination and establishment: well-watered seedlings grow faster and are less palatable to flea beetles than dry, stressed plants. Once the plants have developed several sets of true leaves and are growing strongly, remove the netting to allow pollinator access to the flowers.
Cause 3: Powdery mildew
Powdery mildew can affect mignonette in warm, dry summers, appearing as a white or pale grey powdery coating on the upper surfaces of the leaves, accompanied by curling, puckering, and distortion of the affected foliage. The fungus responsible thrives in conditions where the air is warm and dry but surface humidity on the leaves is sufficient for spore germination: the dry nights of late summer, in particular, create this moisture gradient on leaf surfaces. Crowded plantings where individual plants are growing close together and air does not circulate freely through the foliage are most susceptible.
Mignonette is normally grown in lean, well-drained, poor soil, which produces compact, moderately vigorous growth that is relatively resistant to mildew. Plants that have been over-fertilised or grown in rich, moisture-retentive soil produce soft, lush foliage that is far more susceptible. Powdery mildew on mignonette is primarily cosmetic on plants that are otherwise growing well and approaching the end of their natural season: a late-summer mildew infection on a plant that has been flowering for several weeks is not a significant problem. On younger plants earlier in the season it is worth treating promptly.
How to fix it. Remove heavily mildewed leaves and dispose of them in the bin rather than the compost. Apply a potassium bicarbonate spray or a diluted neem oil solution to the affected plants, coating both leaf surfaces, at the first sign of the white powdery coating. Improve air circulation by thinning overcrowded sowings and removing any surrounding foliage that is shading and compressing the plants. The key prevention is sowing thinly from the outset, keeping at least 15 to 20 cm between plants, and growing in an open position with good air movement. Avoiding overhead watering in favour of watering at the base also reduces the surface humidity that mildew spores need to establish.
Cause 4: Root rot and drainage problems
Mignonette is one of those plants that is more often killed by kindness than by neglect. It is a native of North Africa, where it grows in rocky, alkaline, very free-draining ground, and it has been naturalised and cultivated in the UK since the eighteenth century precisely because it thrives in the chalky, poor, fast-draining soils that defeat many other garden plants. Growing mignonette in heavy clay, in a low-lying position that retains winter moisture, or in a pot standing in a saucer of water will cause the roots to rot. The first visible symptoms are a general deterioration of vigour: the leaves lose their fresh pale green colour, begin to yellow, and curl downward. As the root rot progresses the whole plant wilts and collapses, and examination of the crown at soil level reveals blackened, soft, rotted tissue.
Mignonette also responds badly to overwatering in containers. It is commonly grown on windowsills in pots to bring the scent indoors, and indoor cultivation often results in overwatering because the plant is visible and easy to fuss over. A mignonette in a terracotta pot on a south or west-facing windowsill in well-drained, gritty compost, watered only when the surface is dry, will thrive. The same plant in a plastic pot in peat-based compost kept consistently moist will rot.
How to fix it. Mignonette in badly drained soil cannot be saved once root rot has progressed to the crown; remove the plant and improve the drainage before resowing. For container plants, remove the plant from its pot, cut away any blackened roots, allow the root ball to dry briefly, and repot into fresh, gritty, free-draining compost in a pot with generous drainage holes. Prevention is straightforward: always grow mignonette in free-draining, low-fertility soil (or a 50:50 mix of multipurpose and horticultural grit in containers), avoid watering until the surface is dry, and never allow pots to stand in water. Mignonette actually grows better in poor, alkaline soil than in rich, fertile conditions: RHS trials have consistently shown that chalky or limey soil produces the best plants and the strongest fragrance.
Cause 5: Drought stress and cucumber mosaic virus
Drought stress causes mignonette leaves to roll inward along their length, reducing the surface area exposed to sun and wind as the plant limits water loss through transpiration. The affected leaves take on a slightly dull, grey-green tone and may feel leathery rather than crisp. Unlike the downward curl of aphid-damaged growth or the distorted crumpling of flea beetle damage, drought-induced leaf roll is a clean, uniform inward curl affecting the whole leaf. The plant often recovers quickly once watered, with leaves uncurling within a day or two.
Cucumber mosaic virus (CMV) is a less common but more serious cause of leaf distortion in mignonette. It is transmitted by aphids, including Myzus persicae, and produces a mosaic pattern of light and dark green on the leaves alongside puckering, curling, and general distortion of the young growth. CMV-infected plants do not recover and should be removed and disposed of in the bin immediately to prevent aphids spreading the virus to other garden plants. The main prevention is controlling aphid populations early in the season.
Weld (Reseda luteola) is a taller, biennial relative of mignonette, grown for its yellow dye and naturalised across chalky downland in the UK. It shares mignonette's preference for poor, alkaline, free-draining soil and is similarly susceptible to aphids and flea beetles on young plants, though its tougher, darker foliage generally makes it more resistant than the tender annual species.
Growing mignonette well: prevention built in
Mignonette is direct-sown where it is to flower, from March to May in a warm, sheltered spot. It dislikes root disturbance, so transplanting is best avoided; thin the seedlings to 15 to 20 cm apart and leave them to grow undisturbed. Successive sowings every three to four weeks extend the flowering and scenting period through summer. A south or west-facing position, or a warm windowsill, suits it best: mignonette's fragrance is most intense in warm sunshine.
The growing conditions that keep mignonette healthy are also the most effective prevention for nearly all the problems above. Sow in poor, well-drained, alkaline or neutral soil without added fertiliser or compost: the lean conditions limit soft growth that aphids favour and root conditions that cause rot. Sow thinly and thin to proper spacing to maintain air circulation and reduce mildew pressure. Water at the base and avoid wetting the foliage. Cover seedlings with fine mesh netting in the first few weeks to exclude flea beetles. Do not feed with nitrogen-rich fertilisers: extra nitrogen produces lush, aphid-attractive growth and suppresses the compact habit and intense scent that make mignonette worth growing. Self-sown plants that appear in subsequent years from seed that has fallen naturally are often the most robust, having germinated in exactly the conditions that suit the species.
Frequently asked questions
Why are my mignonette leaves curling?
The two most common causes of mignonette (Reseda odorata) leaves curling are aphids and flea beetles. In spring, colonies of the peach-potato aphid (Myzus persicae) settle on soft shoot tips and cause the young leaves to curl downward and inward. Flea beetles (Phyllotreta spp.) chew small round holes in the leaves and cause ragged edges and marginal curling, particularly on seedlings in dry spells. Less common causes include powdery mildew in dry summers, root rot from overwatering or heavy clay, drought stress, and cucumber mosaic virus.
How do I get rid of aphids on mignonette?
Blast aphid colonies off mignonette with a strong jet of water aimed at the curled shoot tips and leaf undersides, and repeat every two to three days. For persistent infestations, apply insecticidal soap or a diluted neem oil spray, coating both leaf surfaces. Avoid broad-spectrum or systemic insecticides, which kill the ladybirds, hoverflies, and parasitic wasps that provide natural aphid control. Growing mignonette in poor soil without excessive fertilising reduces the soft, lush growth that aphids prefer. Aphid pressure typically drops naturally by early summer as predator populations build up.
What are the small holes in my mignonette leaves?
Small round holes in mignonette leaves, often accompanied by ragged edges and mild curling, are the signature of flea beetles (Phyllotreta spp.). The adult beetles are tiny (1 to 3 mm), dark, and shiny, and jump rapidly when disturbed. They are most active on young seedlings in dry weather. Protect seedlings with fine insect mesh netting immediately after sowing. Keeping the soil consistently moist during establishment reduces damage, as flea beetles attack stressed, dry plants most aggressively. Established mignonette plants tolerate light flea beetle feeding without significant harm.
Can mignonette get powdery mildew?
Yes, mignonette can develop powdery mildew in warm, dry summers, producing a white floury coating on the leaf surfaces alongside curling and distortion. It is most common in crowded plantings with poor air circulation and in plants grown in rich soil or under drought stress. Sowing thinly, watering at the base rather than overhead, and growing in an open position with good airflow reduce the risk. At the first sign of white coating, remove affected leaves and apply a potassium bicarbonate spray. Powdery mildew on mignonette is primarily cosmetic on otherwise healthy plants later in the season.
Why is my mignonette wilting and the leaves curling downward?
Mignonette wilting with downward-curling leaves can indicate either drought stress or root rot, and both can look similar above ground. Check the soil at root depth: if it is bone dry, drought is the cause and the plant will recover with a thorough watering; if it is saturated and the crown smells of decay, root rot has set in. Mignonette prefers sharp drainage and tolerates poor, chalky soil, so it is more commonly harmed by overwatering or heavy clay than by drought. In the right free-draining soil, established plants rarely wilt in typical UK summers.