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Scientific: X Chitalpa tashkentensis
Common: chitalpa
Family: Bignoniaceae
Origin: An intergeneric hybrid cross between Chilopsis linearis and Catalpa bignonioides

Pronounciation: Chi-TAL-pa tash-ken-TEN-sis

Hardiness zones
USDA 6-11

Landscape Use: Oasis landscape design themes, multiple or single trunk residential tree, smaller park tree.

Form & Character: Upright and spreading, open, rangy (correlative inhibition of lateral branching) to perhaps gangly, airy, marginally pendulous, festive when in bloom.

Growth Habit: Deciduous, woody, broadleaf perennial tree, rather vigorous, upright and spreading to 30-feet tall with an equal or greater spread.

Foliage/Texture: Variable alternate leave arrangement, sometimes whorled or ternate, leaves lanceolate and glabrous sometimes slightly reflexed, 2- to 5-inches long, rarely falcate, sometimes drops leaves prematurely in mid summer to early fall, stems and trunk has lenticels, no fall color; medium coarse texture.

Flowers & Fruits: 15 to 40 flowers in a terminal raceme, corollas are zygomorphic, calyx are 2-lobed, color is white to pale or dark pink and often with distinct purple veins, flowers are sterile and produce no fruit.

Seasonal Color: In Phoenix, flowers are grown during late spring and early summer.

Temperature: Tolerant of lower desert heat, though because of its relative sparse canopy it is VERY PRONE to trunk sunscald.

Light: Avoid western exposures with reflected radiation as this tree's trunk will sustain mega-sunscald damage!

Soil: Tolerant of high alkaline soils, though clearly less tolerant than Chilopsis linearis.

Watering: Chitalpa very much needs frequent, regular supplemental water, especially in summer. Its water needs for good performance in Phoenix are much higher than Chilopsis linearis because of its other "eastern" parent, the catalpa tree.

Pruning: Prudently and conservatively use selective thinning and heading of lateral branches to increase canopy density and aesthetics by reducing this tree's normal open, rangy branching habit.

Propagation: Asexually only by stem cuttings.

Disease and Pests: This hybrid tree is highly subject to Thielaviopsis root rot and more critically, Xylella fastidosa (Pearce's disease), a leaf scorch bacteria that normally infects grapes. Otherwise, foliar powdery mildew is usually confined to wet spring conditions, which in central Arizona are increasingly becoming rare (the wet, cool springs of 2020 and 2024 not withstanding) because of climate change in the desert Southwest.

Additional comments: Chiltalpa is an unusual intergeneric hybrid cross bred in Uzbekistan in 1964 by Soviet geneticist Nikolia F. Rusanov. It was introduced into the United States by Robert Hebb of the New York Botanic Garden in 1977. Since 1990, this fruitless botanical wonderfreak can be found growing in Phoenix landscapes. Chitalpa has a relatively sparse canopy, is prone to trunk sunscald, and requires frequent and regular summer water in Phoenix. It is best used away from reflected radiation or intense western exposures. Popular cultivar selections include 'Morning Cloud' (white flowers) and 'Pink Dawn' (deep pink flowers).