Outer leaves of 'Firepower' nandina turn red in winter with the onset of cool temperatures. Figure 4. The bright red foliage of 'Firepower' nandina is very attractive in fall and winter.

Why does my nandina not turn red?

the soil well mulched and water when nature doesn't provide it during the growing season. Temperatures have been warm this fall--that might explain why yours haven't turned red.

Do Nandinas change color?

The upright growth habit of the straight Nandina domestica species indeed resembles bamboo. The green foliage transforms to red for the cooler months. ... The intensity of foliage color depends on whether it is planted in full sun or partial shade.