Agronomic practices and challenges in cultivating Agathosma betulina (P.J.Bergius) Pillans: A review

Abstract

Agathosma betulina (P.J.Bergius) Pillans, commonly known as buchu, is a medicinally and commercially important shrub endemic to South Africa’s Cape Floristic Region. Although valued for its essential oils rich in diosphenol and sulfur compounds, cultivation remains limited by agronomic challenges, sustaining reliance on unsustainable wild harvesting. This review synthesizes current research on buchu’s ecological adaptations, propagation issues, and cultivation constraints, drawing from scientific databases and ecologically similar fynbos species. Buchu thrives in acidic (pH 4.0–6.5), nutrient-poor soils. However, domestication is limited by low seed germination, poor transplant survival (<10 %), and inconsistent essential oil profiles in cultivated plants. These challenges intensify outside its native range, where poor establishment and susceptibility to root pathogens like Phytophthora spp. severely limit ex situ cultivation. Conventional propagation (seeds, cuttings) is unreliable, while micropropagation, though promising, requires optimization to preserve bioactive compound integrity. Postharvest knowledge gaps persist, especially in harvesting timing (to reduce toxic pulegone), drying, and storage. Emerging solutions include seed priming, microbial inoculants (e.g., Cryptococcus laurentii), and precision agriculture techniques. Bridging traditional practices with innovative technologies may address propagation and yield challenges. However, urgent advances in propagation and soil management are vital for sustainable commercialization and conservation of this culturally and ecologically significant species.