Habitat and Hardiness
Jacaranda (Jacaranda mimosifolia) is a native of warm regions of South America, and in the United States, it is winter hardy in U.S. Department of Agriculture plant hardiness zones 9b to 11. It is sensitive to below-freezing temperatures, but cool night-time winter temperatures below 40 degrees Fahrenheit may encourage more prolific blooming in the spring.
Size and Growth Habit
Mature jacaranda trees can reach heights of between 25 and 40 feet, and their horizontal spread may be even wider, making them impressive garden specimens that need plenty of room to grow. The arching habit of their branches also makes them attractive street trees, as their branches will often grow over and shade the street.
Jacaranda trees produce foot-long, pyramid-shaped clusters of blue or lavender flowers in spring and early summer; the tree's long bloom period may last for more than a month. The flowers do not have a pronounced fragrance.
Young jacaranda trees take a considerable amount of time before they begin to bloom. Trees grown from seed may take seven years before they begin to bloom, and some specimens may take as long as 25 years. Grafted trees will reach blooming age more quickly but may still take three to five years before they begin to produce flowers.
Jacaranda trees are not especially demanding in terms of soil conditions. They grow well in sandy soils with good drainage, and nutrient-deficient soil may actually cause them to produce better blooms. They tolerate partial shade, but they will flower best when grown in a sunny location.
Jacaranda is not tolerant of salt, so it's perhaps not well suited to exposed coastal locations, but it does fare well in urban locations, further enhancing its strength as a street tree and as a specimen in the urban garden.
Each flower cluster on a jacaranda tree consists of hundreds of individual blossoms, and as each blossom ages, it falls from the cluster to the ground. This flower drop is often considered one of the tree's desirable characteristics because the colorful flower petals form an attractive carpet on the ground beneath the tree. However, the fallen flowers, as well as seed capsules that drop from the tree later in the season, can be a disadvantage if the tree is near a patio, pool or other location where the mess is not appreciated. Wet flower petals on the ground can also make paths slippery.