Pyrethrum is a perennial flowering crop grown for its natural insecticidal compounds known as pyrethrins. In Kenya, farmers grow it mainly as a cash crop rather than a food crop. It generates income, creates rural employment, and supports export earnings when production is stable. Farmers harvest the flowers, dry them, and process them to extract pyrethrins. These compounds produce natural insecticides used in agriculture, public health, household pest control, and veterinary care. Pyrethrum grows best in Kenya’s highland regions. Major growing areas include Nakuru, Nyandarua, Kericho, Bomet, Nandi, and Elgeyo-Marakwet.
Varieties
Kenya mainly relies on improved local selections and clonal lines rather than distinct commercial varieties. Breeders developed these lines to improve flower yield, pyrethrin content, and disease tolerance. Consequently, farmers prefer high-yielding clones because they produce more flowers per plant. Some types perform better in cooler high-altitude zones above 1,800 metres, while others tolerate slightly warmer transitional areas. In addition, breeding programmes focus on strong flowering ability, uniform growth, and faster recovery after harvest. However, farmers still face limited access to certified planting material, which slows expansion.
Climate & Soil
Pyrethrum grows well in cool and moist highland conditions. It performs best at altitudes between 1,500 and 2,500 metres. Ideally, temperatures should remain between 15°C and 20°C. Higher temperatures reduce flower quality and lower pyrethrin content. Moreover, the crop requires 800–1,200 mm of well-distributed rainfall annually. It suffers when drought occurs during establishment or flowering stages. Well-drained soils support strong growth, while loamy soils perform best due to balanced drainage and nutrient retention. In addition, the crop prefers soil pH between 6.0 and 7.0. Poor drainage, however, increases root diseases and reduces productivity.
Propagation & Planting
Farmers propagate pyrethrum using seedlings or clonal splits. First, they raise seedlings in nurseries before transplanting them to the field. They sow seeds or plant splits in prepared seedbeds or trays under partial shade. After 6–8 weeks, seedlings become ready for transplanting. Farmers then transplant at the onset of rains to improve establishment success. Furthermore, they space plants 60–70 cm between rows and 30–40 cm within rows. This spacing improves airflow and makes weeding and harvesting easier. In addition, farmers prepare land through deep ploughing and incorporate organic matter to improve soil fertility.
Field Management & Harvesting
Farmers control weeds early because young plants compete poorly. Therefore, they weed manually or apply controlled herbicide use. They also use mulch to suppress weeds and conserve moisture. At the same time, the crop responds well to organic manure and balanced fertilizers. Key nutrients include nitrogen, phosphorus, and potassium, which farmers apply based on soil test results. In addition, drip irrigation supports growth during dry periods, although many farmers still depend on rainfall.
Harvesting begins when 50–70% of flowers are fully open. At this stage, pyrethrin content is highest. Typically, harvesting starts 3–4 months after planting and continues in cycles. Farmers pick flowers by hand or use mechanical harvesters on large farms. However, they handle flowers carefully to avoid damage and quality loss. Immediately after harvesting, they dry flowers in thin layers under well-ventilated conditions. Importantly, they avoid direct sunlight to preserve pyrethrin levels. Finally, they store dried flowers properly before milling and extraction.
Uses & Market Potential
Pyrethrum mainly supports the production of natural insecticides. These products serve agriculture, household pest control, public health, and veterinary applications. For instance, farmers use pyrethrum-based products to control crop pests, while public health programmes use them for mosquito control. Similarly, livestock keepers use them to control external parasites.
In addition, pyrethrum contributes indirectly to food security by reducing crop losses from pests and lowering disease transmission. Kenya once led global production and still holds strong export potential. However, competition has increased from countries such as Tasmania, Rwanda, Tanzania, and China.
Nevertheless, demand for natural and biodegradable pesticides continues to grow globally. Therefore, value addition offers strong opportunities through extraction and formulation of sprays, concentrates, and organic pest control products. Furthermore, stronger local processing can increase farmer incomes and create rural jobs. Ultimately, if production stabilises, pyrethrum can regain its position as a high-value industrial crop in Kenya’s agricultural economy.