Why Are My Chamomile Leaves Curling?

Aphids

Aphids colonise chamomile growing tips in spring and early summer, causing the fine, feathery young leaves to curl and cluster around the feeding colonies. The most common aphid on chamomile is greenfly (Myzus persicae and related species). In a well-managed garden, natural predators (ladybirds, hoverfly larvae, parasitoid wasps) typically bring aphid colonies on chamomile under control within 2 to 3 weeks without intervention.

What to do

• Inspect chamomile growing tips from April for aphid colonies. Pinch off and discard heavily infested tips. Small colonies can be squashed between the fingers or removed with a jet of water. Avoid insecticides during chamomile's flowering period as the flowers attract many beneficial insects.

Drought

Drought causes chamomile leaves to wilt, curl inward, and take on a dried, papery appearance. German chamomile, with its tall stems and fine, divided leaves, shows drought stress particularly quickly. Drought also accelerates the transition from vegetative growth to flowering and seed-setting, shortening the life of annual German chamomile significantly.

What to do

• Water chamomile consistently during dry spells. German chamomile in particular needs regular watering to maintain vegetative growth and delay its transition to full flowering and seed-set. Chamomile in pots dries out much faster than garden-grown plants and may need daily watering in hot summer conditions.
• Apply a mulch of compost around the base of garden chamomile to retain soil moisture and reduce watering frequency.

Overwatering

Chamomile, particularly Roman chamomile, dislikes permanently wet conditions. Overwatering in pots or planting in poorly drained garden soil causes the roots to rot, which is expressed above ground as general yellowing, wilting, and the progressive collapse of the plant from the base upward.

What to do

• Grow chamomile in free-draining soil or compost. In pots, use a mix of regular compost and perlite or grit and ensure drainage holes are clear. Water when the top centimetre of compost is dry rather than on a fixed schedule.
• Roman chamomile spreading as a ground cover benefits from being grown on well-drained, slightly sandy or gravelly soil: it thrives on light soils where other plants struggle but declines in clay or poorly drained conditions.

Powdery mildew

Powdery mildew occasionally affects chamomile in late summer, producing white, powdery patches on the leaves. It is most common on plants that have been stressed by drought or grown in humid, sheltered positions. On German chamomile nearing the end of its annual life cycle, powdery mildew is usually tolerated rather than treated.

What to do

• Remove and destroy affected leaves. Improve airflow around densely sown chamomile. Water at the base of plants. For Roman chamomile grown as a perennial, cutting the mat back in late summer and allowing it to re-shoot produces clean, mildew-free growth for the following season.

Frequently asked questions

Why are my chamomile leaves curling?

Chamomile leaves curl most often from aphid infestation, drought, or overwatering. Aphids cluster on chamomile growing tips and cause the feathery young leaves to curl around the feeding colonies. Both German chamomile (Matricaria chamomilla) and Roman chamomile (Chamaemelum nobile) are vulnerable, particularly in spring and early summer when the soft new growth emerges. Drought causes the fine, feathery leaves to wilt, curl, and take on a dried, papery appearance. Overwatering or poorly drained soil causes root rot, which produces yellowing and wilting of the entire plant. Chamomile is generally a hardy, low-maintenance plant; most leaf curling problems are easily resolved.

What is the difference between German and Roman chamomile?

German chamomile (Matricaria chamomilla) and Roman chamomile (Chamaemelum nobile) are distinct plants with different growth habits and uses, though both produce the daisy-like flowers used for chamomile tea. German chamomile is an annual that grows to 60 to 90 centimetres, produces flowers on branching stems, has a slightly more medicinal, intensely aromatic flavour, and is used primarily for dried herbal teas and medicinal preparations. It self-seeds prolifically. Roman chamomile (also called English chamomile) is a low-growing perennial that spreads via runners to form a mat and reaches only 15 to 30 centimetres in flower. It has a somewhat sweeter, apple-like fragrance and is used for both tea and as a fragrant lawn or path plant. The variety 'Treneague' is a non-flowering cultivar used specifically for chamomile lawns. For making tea, German chamomile is most commonly used as it produces more flowers; for ground-cover or a chamomile lawn, Roman chamomile is the correct choice.

How do I harvest chamomile flowers?

Harvest chamomile flowers when they are fully open and the white petals are just beginning to reflex (bend backward) away from the yellow centre. At this stage the flower contains the highest concentration of the essential oils and medicinal compounds that give chamomile tea its characteristic flavour and properties. Harvest in the morning after any dew has dried but before the heat of midday. Pull the flower heads off individually (a chamomile rake, a comb-like tool drawn through the plant, allows faster harvesting of multiple heads simultaneously). Harvest every few days as flowers mature: the more frequently you harvest, the more flowers the plant produces. For drying, spread freshly harvested flowers in a single layer on a rack or tray in a warm, airy spot out of direct sunlight and leave for 1 to 2 weeks until completely dry. Store in an airtight jar away from light and use within a year.

Why is my chamomile dying?

Chamomile most commonly dies from one of three causes: natural end of life (German chamomile is an annual and dies after setting seed, usually in midsummer to late summer), overwatering and root rot (chamomile prefers well-drained soil and is very susceptible to root rot in waterlogged conditions), or bolting in hot weather (German chamomile flowers rapidly in warm conditions and once it has set seed, the plant's life cycle is complete). Roman chamomile, being perennial, is more likely to die from root rot, being smothered by weeds, or from loss of vigour in a congested mat that has not been divided for several years. If your chamomile is an annual variety and has flowered and set seed, it has completed its natural life cycle: collect the seeds for next year and compost the plant.