Its glossy green prickly leaves and bright red berries (produced only by the female plant) are represented in wreaths, garlands and cards wherever Christmas is celebrated.

In the female, flowers are isolated or in groups of three and are small and white or slightly pink, and consist of four petals and four sepals partially fused at the base.

It has been placed on the Washington State Noxious Weed Control Board's monitor list, and is a Class C invasive plant in Portland.

[9][10][11] During the Cenozoic Era, the Mediterranean region, Europe, and northwest Africa had a wetter climate and were largely covered by laurel forests.

With the drying of the Mediterranean Basin during the Pliocene, the laurel forests gradually retreated, replaced by more drought-tolerant sclerophyll plant communities.

Pure stands of hollies can grow into a labyrinth of vaults in which thrushes and deer take refuge, while smaller birds are protected among their spiny leaves.

After the first frost of the season, holly fruits become soft and fall to the ground serving as important food in its native regions for winter birds at a time of scarce resources.

[15] Numerous cultivars have been selected,[16] of which the following have gained the Royal Horticultural Society's Award of Garden Merit:[17] The hybrid Ilex × altaclerensis was developed at Highclere Castle in Hampshire, England, in 1835, a cross between I. aquifolium and the tender species I. perado.

The following cultivars have gained the RHS AGM: Holly berries contain alkaloids, theobromine, saponins, caffeic acid, and a yellow pigment, ilixanthin.

Less spiny varieties of holly were preferred, and in practice the leaves growing near the top of the tree have far fewer spines, making them more suitable for fodder.