According to observations of naturalists and beekeepers.
Where are you?
SOURCE FOR HONEY BEES:
Minor, important in southeastern US
From the maritime forests of Massachusetts, American holly is scattered along the coast to Delaware. It grows inland to several Pennsylvania counties and to extreme southeastern Ohio. It occurs abundantly southward throughout the Coastal Plain, Piedmont, and Appalachians. Its range extends south to mid-peninsular Florida and west to eastern Texas and southern Missouri. It is cultivated in Hawaii.
Ilex opaca is a medium-sized broadleaved evergreen tree growing on average to 10–20 m (33–66 ft) tall, and up to 30 m (98 ft) tall. Typically, its trunk diameter reaches 50 cm (20 in), sometimes up to 120 cm (47 in). The bark is light gray, roughened by small warty lumps. The branchlets are stout, green at first and covered with rusty down, later smooth and brown. The winter buds are brown, short, obtuse or acute.
The leaves are alternate, 5–7.5 cm (2.0–3.0 in) long and 2–4 cm (0.79–1.57 in) wide, stiff, yellow-green and dull matte to sub-shiny above, often pale yellow beneath; the edges are curved into several sharp, spike-like points, and a wedge-shaped base and acute apex; the midrib is prominent and depressed, the primary veins conspicuous; the petiole is short, stout, grooved, thickened at base, with a pair of minute stipules.
The flowers are greenish-white, small, borne in late spring in short pedunculate cymes from the axils of young leaves or scattered along the base of young branches. The flowers are pollinated by insects, including bees, wasps, ants, and night-flying moths.
American holly begins flowering in April in the southern parts of its range and in June at its northern limits. The fruit ripens from September through December and remains on the tree through most of the winter.