Valued for its tolerance of both soil and climate extremes, Jerusalem Thorn has long been cultivated as an ornamental tree in warm climates throughout the world. A member of the legume family, it grows quickly at first, then slows to an eventual fifteen to twenty-five feet tall and wide with a graceful, spreading habit and picturesque form. The sparse foliage of the Jerusalem Thorn is bright yellow green, composed of thorny branchlets and six- to nine-inch-long compound leaves with many tiny leaflets. These leaflets are shed quickly in drought or cold, leaving just the midribs of each leaf persisting on the tree. Flowering is showy, with three- to seven-inch-long clusters of half-inch, fragrant yellow blossoms produced over a long period in the spring and sporadically at other times of the year. Flowers are followed by two- to six-inch-long tan seedpods.
Jerusalem Thorn is tolerant of almost any type of soil, even strongly alkaline ones. It is also tolerant of excessive heat as well as temperatures as low as 15° F. Because of its finely textured foliage, the filtered shade cast by this tree allows for the growth of many kinds of drought-tolerant plants underneath it, and it can be spectacular as a centerpiece tree in a cactus and succulent garden. It is native to the southwestern United States and Mexico. It also grows successfully in many parts of the southern United States. This tree is particularly adapted to desert climates but it also grows well in humid tropical and subtropical climates and it does not need supplemental irrigation once established because it is so drought resistant.
- Scarify the seeds by nicking or sanding the seed coat.
- Soak the seed in water for several hours.
- The seeds like moist, well-drained soil. Prepare a mixture of half potting soil and half sand, perlite or vermiculite. Put the soil in a pot. Water the mixture so that it is moist but not wet.
- Put the seeds on the soil.
- Cover the seeds with a thin layer of soil.
- Water the seeds.
- Place the pots in an area with warm temperatures in full sun or part shade.
- When the seedlings are a few inches tall, they can be transplanted.