Yellow Trumpetbush (Tecoma stans ) grows wild here in the foothills around Tucson. A good place to see these yellow-flowered, native shrubs is at mile marker 3 along the Catalina Highway north of Tucson, which is where I photographed these Yellow Trumpetbushes this August.
Yellow Trumpetbushes are also common garden shrubs here in Arizona, and if given some water, they will bloom from mid-April to November. These native, subtropical plants are frost-sensitive and will die back to the ground at 20 °F (-6.7 °C), but they will re-sprout again from the roots.
Because of their frost-sensitivity, Yellow Trumpetbushes do best in warmer city areas and on south-facing, rocky slopes, such as along the lower Catalina Highway. South-facing slopes have an unique micro-climate because they absorb the maximum amount of warm sunlight in the winter, and the slope keeps the cold, frosty air from settling on the plants there. Because of this micro-climate, not only do frost-sensitive species thrive there, but spring wildflowers will bloom earlier on these south-facing foothill areas than in the valley below where the cold air settles.