COMMON NAMES: PARKINSONIA, JERUSELUM THORN, RETAMA, HORSEBEAN, CLOTH-OF-GOLD, CROWN-OF-THORNS, BARBADOS FENCE FLOWERS, PALO VERDE, MEXICAN PALO VERDE
Parkinsonia aculeata (park-kin-SOH-nee-ah ak-you-lee-AH-tah)
Fabaceae (Legume, Bean or Pulse Family)
HEIGHT: 12 to 30 feet, has been seen growing up to 40 feet.
SPREAD: 15 to 20 feet
FINAL SPACING: 12 to 15 feet
NATURAL HABITAT AND PREFERRED SITE: Native along the Rio Grande in the Rio Grande Valley, best will adapt to a wide range of soils. It can grow in wet soils but is extremely drought tolerant and will do very well up through the center of Texas.
IDENTIFICATION INFORMATION: Graceful, airy tree with long thin compound leaves, yellow summer flowers green bark and heavily armed with thorns.
FLOWERS AND FRUIT: Fragrant yellow flowers in the spring or throughout the summer, especially after rains. Racemes are 5 to 6 inches long. The pea-shaped flowers persist for at least a week. Fruits form as slender pods 2 to 4 inches long, constricted between the seeds, brown at maturity. Seeds are green, turning brown at maturity.
BARK: Bark is thin, smooth, green, turns reddish brown with small scales on older trunks.
FOLIAGE: Leaves are compound with tiny leaflets. Overall leaf is 8 to 16 inches long. Leaflets are only 1/3 of an inch long or less. The leaf mid rib, branches and twigs are green so they also provide photosynthesis.
CULTURE: Parkinsonia is easy to grow in a wide range of soils, even high salt conditions. Can grow as far north as Dallas but risks freeze damage there during severe winters. Grows best in the moist, deep soils but is strongly drought tolerant. During drought it shed the small leaflets leaving only the mid ribs of the leaves which are green and can continue to manufacture necessary sugars for survival. Fast growing when young, relatively short lived, tolerates moist soil but doesn’t like sopping, heavy, wet clay soils.
PROBLEMS: Freeze damage possibilities in the northern half of the state. Seedlings can become somewhat a problem by sprouting up all over the place.
PROPAGATION: Easy to grow from cuttings or seed but acid or physical scarification treatment is needed to aid germination. Physical damage such as filing the seed coat and/or soaking in liquid humate or seaweed can also aid germination.
INSIGHT: It is probably risky to invest a lot of money in this plant for use north of Austin.