Parkinsonia aculeata Jerusalem Thorn Seeds

About this species

Parkinsonia aculeata is an accepted Fabaceae species native from the south-western United States through Mexico and tropical America. Kew records it as a shrub or tree of desert and seasonally dry tropical habitats. It is known as Jerusalem thorn or Mexican palo verde and has green photosynthetic branches, yellow flowers and sharp spines.

Also known as: Mexican palo verde, Palo verde, Jelly bean tree, Horsebean, Retama, Palo de rayo and Parkinsonia thornberi.

Sowing guide

1. Abrade one small point of the hard coat, stopping before the pale inner tissue is damaged.
2. Soak treated seeds in room-temperature water and note which ones swell.
3. Sow in a deep pot of very free-draining medium and cover to about one seed thickness.
4. Keep warm and evenly moist until emergence, never leaving the container saturated.

Hard-coated seed may remain dormant until water can enter. Scarification must be shallow and controlled. Dryland adaptation applies to established plants; a germinating seed still needs steady moisture without airless waterlogging.

Seedling care

Give seedlings increasingly strong light and excellent drainage. Pot on before roots become confined and water thoroughly, then let the upper surface begin drying. Protect young growth from severe cold and handle developing thorns carefully.

The species is thorny and invasive in a number of warm regions. Check current local regulations and invasive-species advice before sowing or outdoor planting, and prevent seed escape. Use a contained site well away from paths, livestock areas and utilities.