Perennial of the Polemoniaceae family, this cultivar of Phlox subulata shares the North American origin of the species, naturally present on rocky outcrops and dry slopes in the eastern United States. The precise origin of the 'Holly' cultivar is not clearly documented in the reference sources consulted.
It forms a dense and vigorous cushion, 8 to 12 cm in height in bloom, with a slightly domed habit. The woody stems at the base bear persistent, dark green, linear-subulate leaves, tight and prickly to the touch, which remain well-furnished after flowering.
The flowers are bright pink to true pink-mauve, with a well-defined and visible dark red central eye. The petals, broad and slightly overlapping, give each flower a full and rounded appearance, a characteristic noticeable upon close examination. The hue, bright and luminous, oscillates depending on the sunlight between deep pink and a warmer shade leaning towards pink-magenta. The flowering is very abundant and almost entirely covers the foliage.
In its natural habitat, the species blooms from April to June. In cultivation, 'Holly' generally blooms in April-May. It requires full sun, well-drained soil, and withstands summer drought well once established. Stagnant moisture in winter is unfavorable to it.