Baccharis halimifolia groundsel bush Asteraceae BAHA; Bx, cm (planted), pb; Q, a, bp; fa, ft, j, wl; NY, bl, iw, rr; K, fl, fs, m; R, c, ca, fk, gr, h, mls, ok, pr, sm, t, wp, x; 

baccharis-halimifolia-groundsel-tree-staminate-plant-mhbg-pond-edge-in-park-near-rehoboth-beach-de-2016-9-17

Baccharis halimifolia (groundsel tree; staminate plant).M.B. Gargiullo.Park near Rehoboth Beach DE. 9/2016

Baccharis halimifolia is a shrub 1-3 m tall, bark fibrous gray-brown, new growth green, slightly sticky. 

Baccharis-halimifolia.Forest and Kim Starr.luirig.altervista.org

Leaves at Loxahatchee National Wildlife Refuge, Florida – Credit: Forest & Kim Starr – Plants of Hawaii – Image licensed under a Creative Commons Attribution 3.0 License, permitting sharing and adaptation with attribution.

Leaves alternate, stalk short, blade to 6 cm long, 4 cm wide, wedge shaped, upper half coarsely toothed; upper leaves narrow, entire, surface covered with sticky resin, a deterrent to attack by many insects; leaves expand mid May; winter plant leafless 121 days (Britton 1874). 

Flowers very small, inconspicuous, tubular, thread-like, radially symmetrical (discoid), no rays; sexes on separate plants (dioecious); female flowers white-plumed, male flowers flat, yellow due to copious pollen; flowers clustered in dense heads, arising from the expanded top of the floral stalk, and surrounded at their base by small bracts in several overlapping rows, 0.4-0.6 cm tall; heads in branched clusters amid small leaves (bracts); wind pollinated; blooms and fruits Aug.-Oct. 

baccharis-halimifolia-groundsel-bush-fruit-plumes-michael-stanton-corsons-inlet-state-park-10202016

Baccharis halimifolia (groundsel bush; fruit plumes).Michael Stanton.Corson’s Inlet State Park.10.20.2016

Fruit dry, 1-seeded, achenes, with white plume, wind dispersed into winter. Male plants senesce earlier in Autumn than females.

Wetland status: FACW. 

Frequency in NYC: Frequent. 

Origin: Native. 

Habitat: High salt marsh, beach margins, moist fill near shore soil pH 5.5-7.8 (USDA, NRCS 2010). Not shade tolerant. 

Leaves at Loxahatchee National Wildlife Refuge, Florida - Credit: Forest & Kim Starr - Plants of Hawaii - Image licensed under a Creative Commons Attribution 3.0 License, permitting sharing and adaptation with attribution.

Leaves at Loxahatchee National Wildlife Refuge, Florida – Credit: Forest & Kim Starr – Plants of Hawaii – Image licensed under a Creative Commons Attribution 3.0 License, permitting sharing and adaptation with attribution.

Notes: Very much like Iva frutescens, but generally found on higher ground. Leaves eaten by two species of Chrysomelid beetles, Trirhabda bacharidis, a specialist and Paria thoracica, more of a generalist feeder, the larvae are root feeders. Flowers are attacked by larvae of several flies (Krischik and Denno 1990).  

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