Classification
 Nomenclature
Scientific Name:
Heracleum mantegazzianum Sommier & Levier (1895)
Vernacular Name(s):
Cartwheel flower; Cow parsnip; Giant hogweed
 Description

Erect biennial. Stems hispid, hollow, grooved, reddish purple blotched and spotted, particularly toward base, up to 350 cm high and 10 cm diam. Basal lvs moderately hispidulous below, sparsely above, pinnately 3-foliolate, petiolate; leaflets ovate to ovate-lanceolate, deeply ternately or pinnately lobed and irregularly double serrate, up to 50–(100) cm long; lobes usually acute to acuminate; stem lvs similar to basal, with petiole often reduced to sheathing part only; petioles reddish purple blotched and spotted. Umbels (20)–30–60 cm diam.; rays (20)–50–70–(100), the primary umbels > 50-rayed; bracts usually c. 12, linear, 10–15 mm long; bracteoles 8–12, linear, up to 15 mm long. Fls numerous, white; outer fls irregular and up to 15 mm diam. Fr. glabrous, ovate-elliptic, light brown, c. 10 mm long; vittae conspicuous, 0.5–1 mm wide at base.

[From: Webb et al. (1988) Flora of New Zealand. Volume 4.]

 Biostatus
Exotic
 Phenology

Flowering: Dec.–Feb.

 Bibliography
Biosecurity New Zealand 2012: Regional Pest Management Strategies Database. http://www.biosecurityperformance.maf.govt.nz/
Biosecurity New Zealand 4 Aug 2011: Unwanted Organisms Register. http://www.biosecurity.govt.nz/pests/registers/uor
Biosecurity New Zealand 2008: National Plant Pest Accord. MAF Biosecurity New Zealand, Wellington.
Connor, H.E. 1977: The Poisonous Plants in New Zealand. Edition 2. Government Printer, Wellington.
Ministry for Primary Industries 23 Feb 2017: Unwanted Organisms Register. Version 02.01.02. https://www1.maf.govt.nz/uor