Identification: Tiny—barely larger than Eastern Tailed-Blue. Almost never seen with wings open. Below: FW and HW bright green or blue-green with white postmedian lines bordered with brown patches on both sides, and 2 white basal HW spots. Topmost white mark in FW postmedian band is displaced outwardly, and topmost white mark in HW band is displaced inwardly. Similar hairstreaks: Juniper Hairstreak is green rather than blue-green, the postmedian lines are bordered by brown only on the inner side, and the top spots in the postmedian bands are not displaced. Hessel's is generally confined to the immediate vicinity of cedar swamps.
NJ Status and Distribution: Resident. Classified as Special Concern in NJ. Uncommon and local from Burlington and Monmouth counties south. Formerly reported from North Jersey.
Habitat: Wetland forest edges and openings with Atlantic White Cedar. Openings typically are shrubby with some cedar regeneration. Unlikely to visit gardens unless they border a cedar swamp.
Flight Period: Mainly one brood—mid-April to late May. Some years there is a small second brood in July. Extreme dates: 4/4—5/20.
Larval Food Plants: Atlantic White Cedar (Chamaecyparis thyoides).
Overwintering Stage: Pupa.
Best Locations: Wharton SF, Bass River SF; Penn SF, Belleplain SF, Woodland Township (Rt. 72), Oswego River Preserve.
Comments: Best searched for in shrubby openings adjacent to stands of Atlantic White Cedar. Likes to nectar on Sand Myrtle (Leiophyllum buxifolium), Highbush blueberries (Vaccinium), Sweet Pepperbush (Clethra alnifolia), and Leatherleaf (Chamaedaphne calyculata).
It is highly unlikely that one would see both green hairstreaks together, as Juniper is found in dry habitats near stands of Eastern Redcedar, whereas Hessel's occurs in close association with wetlands dominated by Atlantic White Cedar.
First described as a species in 1950 from a location near Lakehurst, so if NJ ever adopts a state butterfly, this should be it! No doubt the NJ Irish would choose this emerald butterfly as their favorite species.
Woodland Twp., Burlington Co., NJ, 5/7/11, on Sand Myrtle.
Atlantic White Cedar (Chamaecyparis thyoides) is the only known host plant for Hessel's Hairstreak.
Sand Myrtle (Leiophyllum buxifolium) is a small, spring flowering, shrub of the Pine Barrens. It is the primary source of nectar for Hessel's Hairstreaks.