A unique cultivar of Hybrid Spring Phlox named Phlox ‘;Rocky Road Magenta’; characterized by vigorous, dense, multi-stemmed, winter-hardy habit with short, bright glossy-green, linear leaves. Flowering begins in mid-April and continuing for nearly five weeks on heavily-branched peduncles and completely cover the plant in peak season. Petals are vibrant, magenta-purple with a small dark-purple eye. Petal apices are lightly notched. The new plant is able to withstand dry conditions once established, and the foliage stays clean and resists mildew. The new plant is especially suitable for the landscape as a potted plant and in the garden as a specimen or en masse.