Invasion of Giant Hogweed (Heracleum mantegazzianum): Working with Landowners and the Public Kelly Kearns, Invasive Plant Coordinator 608-267-5066 [email protected] Joshua Kraemer, Applied Ecological Services Jill Hapner, SEWISC Coordinator We’ll cover:

• Hogweed distribution • Toxicity • ID characteristics and look-alikes • Case study – Sheboygan – Coordination – Working with landowners, media and public – Control and monitoring Giant hogweed range Presence in Wisconsin

100s of reports annually Only verified in 4 counties (Iron, Portage, Leslie J. Mehrhoff, University of Connecticut, Bugwood.org Manitowoc, Sheboygan) Phytophotodermaltoxicity

• Can cause serious skin blisters when sap gets on skin in sunlight • Usually more toxic than wild parsnip or cow parsnip • Non-flowering plants can be toxic Giant hogweed characteristics

• Monocarpic perennial: Blooms May to July • Usually blooms at 5+ years • Often found along roadsides, vacant lots, and in moist woodlands or wetlands • Large infestations in some eastern states and European countries • Federal noxious weed It really is GIANT Distinguishing characteristics

• Flowering plant size

• Basal leaf size

• Inflorescence/umbrella size

• Number of rays in an inflorescence

• Shape of leaf

• Stalk diameter • Purple spots and long hairs at the leaf nodes “Lookalike” species American cow parsnip (Heracleum lanatum) Poison hemlock - Native - (Conium maculatum) - Invasive -

Great angelica (Angelica atropurpurea) - Native - Flowering plant size Giant hogweed •8-15 ft tall

Cow parsnip • 3-8 ft tall

Great Poison angelica hemlock •Up to 8 ft •4-10 ft tall Inflorescence/umbel size Giant hogweed •Umbels up to wide •Umbrella shaped Cow parsnip •Slightly domed on top •Umbels 5-12” across •50 or more rays •Flower heads flat on top •15-30 rays

Great angelica Rhiannon Fernandez •Spherical umbel •Secondary umbels also Poison spherical hemlock •Many smaller umbels •2-4” across •Umbels domed on top Giant hogweed •Up to 5 ft wide, basal leaves Leaves up to 3 ft •Underside has coarse white Cow parsnip hairs •Up to 2 ft wide •Compound •Pinnately compound •Deeply lobed •Lobe more shallow •Less incised than hogweed

Great angelica •Pinnately compound leaves IPANE Poison hemlock •Alternate, pinnately compound •Small, fern-like •Broadly triangular shape •Veins end at tips of tooth margins •Hairless and shiny Flowering Stalks Giant hogweed •2+” diameter Cow parsnip •stems are ribbed, hollow, green with purple •1” diameter mottling •Non-mottled, slightly •covered in coarse, white hairs reddish flower stems •thick circle of hairs at base of leaf stalk •Fine white hairs •Mainly green and ridged •1 to 2 inch diameter

Great angelica Poison •Smooth, purplish stem hemlock •Stems are hollow, ridged, and hairless; Image ID: 2013/pct11L purple mottling near base Project Locations – Sheboygan, WI Discovered in 2016 • Semi-rural residential area – Weeden Creek Road – 8 homeowners with adjoining backyards • Railroad right-of-way Weeden Creek Road Railroad ROW South East WI Invasive Species Consortium (SEWISC) Coordinating South East WI Invasive Species Consortium (SEWISC) Coordinating • Population reconnaissance South East WI Invasive Species Consortium (SEWISC) Coordinating • Population • Work with reconnaissance homeowners and railroad officials and homeowners South East WI Invasive Species Consortium (SEWISC) Coordinating • Population • Work with reconnaissance homeowners and railroad officials and homeowners • Press releases, media interviews, responding to reports from public South East WI Invasive Species Consortium (SEWISC) Coordinating • Population • Work with reconnaissance homeowners and railroad officials and homeowners • Press releases, media interviews, • Hire and coordinate responding to reports with contractor to from public treat and monitor sites repeatedly

Control • Early Summer – Spray infestation/Remove flower heads • Mid-Summer – recheck/retreat (new germinants and smaller plants hidden under the larger ones) • Repeat yearly until seed bank is depleted Chemical Selection • Escort (Metasulfuron) – Excellent control Application rate: 1.5 oz/acre (1 tsp/gal.) - keep agitated • Excellent Control – dry areas only • Aquasweep (triclopyr and 2,4-D) Application rate: 3oz/gal Excellent Control – wet areas, will not kill grasses/sedges • Garlon 3A (triclopyr) Application rate: 2.5% (6oz/gal) Good Control – wet areas, will not kill grasses/sedges Personal Protective Equipment (PPE)

Tyvek suit Nitrile gloves Rubber boots Read herbicide label for PPE requirements

*Photo to left from New York State - Dept. of Environmental Conservation website. Before Treatment Photos After Treatment Photos (2 weeks) After Treatment Photos (4 weeks) Year 3 - Sheboygan’s Weeden Creek

• Weeden Creek site reduced to approx 1/4 acre, with 250 plants, 30 were flowering (flower heads cut and bagged) • Sprayed Date: 7-5-18 & 7-24-18 • Follow-up monitoring showed 1 flowering plant (seed head cut and bagged) and 15 rosettes. All were sprayed again Cost of Coordination and Control

Costs for 2 Sheboygan sites over the past 3 years:

2016: $5,919 2017: $4,520 2018: $3,940 Total: $14,379.00

Funding from the DNR Forestry Division and federal Great Lakes Restoration Initiative Questions?