Ashoka (Mast Tree): Where Monoon longifolium Grows in India and How to Plant It

The mast tree is native to south India (Kerala and Tamil Nadu) and Sri Lanka, and is widely cultivated across India and the tropics. eFlora of India has records of planted trees from Delhi's parks and roadsides, Haryana, Pune and Bangalore, and Rajasthan forest working plans record it as ashapala and ashok. Wherever it is planted, it stays green all year, makes a neat living screen for avenues and boundaries, and feeds birds and butterflies.

Regions. It grows well with the monsoon in the northern plains, central India, the east, the north-east, the west and east coasts and the southern peninsula. Two regions need care. In the north-west dry zone it needs more water than desert natives such as Khejri, so plan regular watering through its first years. In the Himalaya, Top Tropicals describes the mast tree as frost sensitive, so plant it only in frost-free lower valleys and cover young plants on cold nights. The planting months for each region are in the Planting calendar.

Climate. NParks Singapore lists it as drought tolerant, but young plants need regular watering in their first years and are sensitive to frost wherever winters turn cold.

Soil. It does best in deep, well-drained loam or sandy loam enriched with organic matter. Avoid waterlogged or hard-pan sites. No reliable soil pH range has been published for it.

Plant it alongside natives. Outside its native south India it is a garden and avenue tree, not a low-water restoration tree. As practical advice, plant it alongside the native trees of your area (in the north-west, for example, Khejri, Neem and Peepal), not instead of them.