According to observations of naturalists and beekeepers.
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Calluna vulgaris (common heather, ling, or simply heather) is the sole species in the genus Calluna in the flowering plant family Ericaceae. It is naturalized in North America from Newfoundland west to Michigan and south through Nova Scotia and the New England states to the mountains of West Virginia. It is widespread throughout Europe.
Heather is an evergreen ascending shrub, usually reaching 3.3 feet (1 m) in height. Growth form varies from low and sparse to dense and bushy. The opposite leaves are 0.08 to 0.16 inches (0.2-0.4 cm) long, and flowers are in axillary or terminal racemes. The root system is lateral and mostly buried within the top 4 inches (10 cm) of soil. On poorly drained sites, roots may extend to 8inches (20 cm) below ground. Young plants have a taproot that is later obscured by increased growth and branching of lateral roots. A surface mat is formed by adventitious roots and fine branches of the main root system.
In North America heather flowers from July to November.