1. Responding to Horticulture Inquiries
Weeds/Invasive plants
Mark Renz
Extension Weed Scientist
mrenz@wisc.edu

2. 2012 weather and predictions
• Record breaking spring
– Warmest March on record
– Typical to colder spring after (several frosts
• How will this impact weed populations?
– Early warm-up will favor biennials and perennial
weeds
– Some annuals got a 2-4 week headstart

3. Average date of first Days earlier
Weed emergence as of
Weed species emergence 1998-2000 emergence
4/4/2012
(range observed in days) than average^
ANNUAL GRASS WEEDS
Barnyardgrass May 3rd (8) N
Fall panicum May 5th (6) N
Giant foxtail April 27th (2) Y* 23
Green foxtail May 3rd (3) N
Large crabgrass May 14th (9) N
Shattercane May 13th (10) N
Wooly cupgrass April 30th (6) Y* 26
Yellow foxtail April 30th (7) Y* 26
ANNUAL BROADLEAF WEEDS
Bur cucumber April 29th (5) N
Common ragweed April 7th (28) Y* 3
E. black nightshade April 30th (16) Y
Giant ragweed April 8th (32) Y
Common Lambsquarter April 18th (22) Y* 14
Redroot pigweed May 9th (2) Y* 35
Waterhemp May 5th (1) Y* 31
Wild cucumber April 16th (10) Y* 12
th

4. Pest management steps
1. Pest identification = WHAT IS IT?
2. Population size = HOW MUCH?
3. Select appropriate control tactic =
WHAT CAN I DO?
4. Monitor and adapt management over time =
WHAT CAN I DO BETTER?

5. Lots of resources to
aid in identification
• Books
• Field guides
• Websites
• Ask an expert
• Interactive tools
– CDs, Websites

6. Resources I Frequently Use
• Books
– Weeds of the Northeast
• 300 species, including woody species, with four or more colored pictures
• short cut identification tables
• a narrative (including a useful description of how to distinguish from
similar weeds)
– Ontario Weeds
• black and white line drawings of 315 species with 28 pages of color plates,
each with six pictures
• a narrative (including a useful description of how to distinguish from
similar weeds
• Available on-line at: http://pubont.stores.gov.on.ca/pool/.
• Websites
– WeedID@wisc.edu
– UW-Herbarium http://www.botany.wisc.edu/wisflora
– Virginia Tech http://www.ppws.vt.edu/weedindex.htm
– Missouri plants http://www.missouriplants.com/index.html
– Ontario weeds www.ontarioweeds.com

7. Currently what do you use to identify
unknown weeds
Select as many as apply
1. Books/field guides 12% 12% 12% 12% 12% 12% 12% 12%
2. weedid.wisc.edu
3. UWEX YouTube videos
4. Other web-based tools
5. UW extension
(agent/specialist)
6. Non extension expert
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8. New Weed ID TOOL
http://weedid.wisc.edu
• 355 of the most
common weeds of
Wisconsin entered
• Allows for selection
of known traits to
reduce the potential
weeds that fit this
criteria

9. Step 1: Select the type of weed you are
trying to identify.
• BROADLEAF (269 species):
– These herbaceous (non-woody) plants typically produce
noticeable flowers. Leaves are often broad with netted
veins, but they may also be narrow and veinless.
• GRASSLIKE (51 species):
– These herbaceous (non-woody) plants lack noticeable
flowers. The leaves are ribbon-like with parallel veins, and
are often tightly rolled.
• WOODY (54 species):
– Trees, shrubs, and sub-shrubs with obvious woody stems
that persist year after year.

10. Step 2: Begin your search by answering just a few questions you
are confident are correct and are distinct for this weed. If your
selections result in too many plants, continue to answer additional
questions to narrow the number of results.
WARNING: Avoid answering too many questions
as one incorrect answer can eliminate your
desired weed from the results. Therefore, it is
better to answer FEWER questions that are
UNIQUE to your weed (such as if your weed has
spines, thorns, or prickles).

11. What do we ask?
• Broadleaf and woody weeds
– Where was it found?
– General characteristics
– Leaf characteristics
– Stem characteristics
– Floral characteristics
• Grasslike weeds
– Where was it found?
– General characteristics
– Vegetative characteristics
– Inflorescence/Floral characteristics

12. Demonstration
• http://weedid.wisc.edu

13. Dandelion example
• If just enter flower color
– 76 matches
• If also entered milky sap
– 14 matches
• If also entered perennial
– 6 matches

14. What would like improved for
weedid.wisc.edu?
Select all that apply
17% 17% 17% 17% 17% 17%
1. More help buttons
2. Access to information
for each species
3. More/better ID
pictures
4. Better pictures
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15. What do you do if you can’t identify this
plant from the website?
• Try to identify to family or genus then use other
resources (next slide)
• Take a picture and email it to an expert
• Send a sample in for identification through an agent
• Who agents will contact if they can’t identify
– Annual Crops Vince Davis
– Horticultural Crops Jed Colquhoun
– Perennial Crops/Natural Areas Mark Renz
– Turf: http://www.plantpath.wisc.edu/tdl/

16. When advising on management get as
much information as possible
1. Where is the weed growing?
2. How much of it do you have?
3. How long has it been there?
4. What control options are you willing/able to
conduct

17. Tools for Management
• Manipulation of the environment (e.g.
Plant competition)
• Physical management (e.g. mowing)
• Herbicide
• Prevention
• Burning
• Biological control
• Grazing

18. Understand the biology
of weeds!
• How do they reproduce and
spread?
– Annuals
– Biennials
– Creeping Perennials
– Simple Perennials

19. Prevention
• Washing equipment to
remove soil and plant parts
from infested areas
• Use of weed free inputs:
– hay and straw
– free gravel, fill, top soil
– compost
• Keep adjacent areas weed
free

20. Common Herbicides For
Homeowners
• Need to look at active ingredients
• Common Active ingredients
– Glyphosate
– Bareground (glyphosate + Imazapic or
Imazapyr)
– Turf (2,4-D, Dicamba, triclopyr and/or MCPP)
– Brush/Poison ivy (Triclopyr)
– Pre (Trifluralin, Pendimethalin, corn gluten
meal)

21. How to read a label
• Active ingredient
• Environmental
restrictions/hazards:
• Directions for use
• Specific information for
site

22. Herbicide Use Tips
• Read and follow label directions on all chemicals.
– Use correct rates
– Calibrate your sprayer
• Be sure that chemicals are mixed thoroughly
• Never spray when it is windy
• Spray only the targeted area
• Be aware of properties of herbicides
– Read environmental restrictions part of label
• Some volatize when air temperatures are > 80F.
• Some persist in the soil for extended periods
• Some can leach into groundwater

23. Invasive plants
Mark Renz
Extension Weed Scientist
UW-Madison
mrenz@wisc.edu

24. Pest management steps
1. Pest identification = WHAT IS IT?
2. Population size = HOW MUCH?
3. Select appropriate control tactic =
WHAT CAN I DO?
4. Monitor and adapt management over time =
WHAT CAN I DO BETTER?

25. Invasive plant ID videos
http://fyi.uwex.edu/weedsci
– Black swallow-wort – Japanese hop
– Bull thistle – Leafy spurge
– Bush honeysuckles – Perennial pepperweed
– Canada thistle – Plumeless thistle
– Creeping bellflower – Poison hemlock
– Dame’s rocket – Spotted knapweed
– Garlic mustard – Teasels
– Hill mustard – Wild chervil
– Japanese hedge parsley – Wild parsnip

26. Factsheets on ID and control
New FACTSHEETS AVAILABLE
• http://fyi.uwex.edu/weedsci 1. Asian bittersweet
2. European marsh thistle
FACTSHEETS 3. Musk thistle
1. Wild parsnip 4. Plumeless thistle
2. Japanese knotweed 5. Bird’s-foot trefoil
3. Japanese honeysuckle 6. Black locust
4. Bush honeysuckle 7. Common tansy
5. Dame’s rocket 8. Crown vetch
6. Creeping bellflower 9. Field bindweed
7. Buckthorn 10. Japanese hop
8. Garlic mustard 11. Japanese stiltgrass
9. Spotted knapweed 12. Leafy spurge
10. Black Swallow-wort 13. Multiflora rose
11. Teasels 14. Privets
12. Hedge-parsley 15. Purple loosestrife
13. Canada thistle 16. Quackgrass
14. Perennial pepperweed 17. Sericea lespedeza
15. Poison hemlock 18. Sweet clovers
16. Hill mustard 19. Tree of heaven
20. Wild chervil

27. What is on a factsheet?
• Detailed control information that emphasizes:
– Timing(s) to conduct method
– Effectiveness in season and 1 year after
– Caution/remarks on use
• Warning, it contains management methods
for NOVICES AND PROFESSIONALS

28. Introduction to the MIPN Control
Database
mipncontroldatabase.wisc.edu

35. Other Resources
• http://fyi.uwex.edu/weedsci
1.Brush management in WI
2.Thistles in pastures and beyond
3.Herbicide effectiveness table
4.CRP mid-contract management
1.Mid-term/contract management cool
season grasses (smooth brome)
2.Invasive plant management

36. We are asking for your help!
• Please contribute invasive plant location data
for Wisconsin
– Focusing on species actively spreading in the state
• Created a resource for you to add species
location: GLEDN
– Need
• GPS or able to find GPS location from a map
• Access to a computer

37. GLEDN Website
www.gledn.org
• WEBSITE FEATURES:
– the ability for casual observers to report a sighting
– a network of professionals to verify new sightings
– email alerts of new sightings, including data from
all data providers across the region
– maps of species distributions across data
providers
– easy communication channels among
stakeholders

39. Simple Report Form

40. Expert Verification
• Recruiting verifiers to help verify submissions
– Customizable by county and invasive plant species
– An email will be sent to verifiers when a new species
is ready for review
• Once verified submission will be on the
distribution map
• If interested in becoming a verifier contact me
– mrenz@wisc.edu

41. Signup for email alerts
• Can get alerts for species of concern to
specific geographic areas
– Currently based on states and counties

42. What do we do with the data?
• Share it with everyone
– Contributing citizens
– Other data management providers
– Local, state, federal agencies
– Researchers
• Create habitat suitability maps
– Predict potential spread
– Improves survey work
– Target high probability species for
education/eradication

43. Wild Parsnip
Black = Low Probability
White = High
Probability
1 inch : 50
miles

46. List of data management
systems contributing data
To get involved with the Great Lakes Early Detection Network or the Global Invasive Species
Information Network, please email
Alycia Crall (crall@wisc.edu)
Funding and support provided by:

47. Are you interested in being
involved with GLEDN?
20% 20% 20% 20% 20%
1. Contribute invasive
species location data
2. Join early detection
network/email
3. View species distribution
4. Become a verifier
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48. Early Detection Species in SE
Wisconsin
• Japanese hedge parsley
• Poison hemlock
• Black swallow-wort
• Wild Chervil

49. Dan Tenaglia, Missouriplants.com, Bugwood.org
Japanese hedge-parsley (Torilis japonica)
WI DNR
Dan Tenaglia, Missouriplants.com, Bugwood.org
WI DNR

50. Spreading hedge-parsley (Torilis arvensis)
Mark W. Bierner
Mark W. Bierner Elizabeth Czarapata

51. Hedge-parsleys
(Torilis sp.)
• NR 40 Status –
– Japanese hedge-parsley: Prohibited/Restricted.
– Spreading hedge-parsley: Prohibited.
• Areas Invaded – Disturbed uplands (ROWs, diteches).
• Life History - Biennial.
• Key ID
– Grooved stem with noticeable joints.
– Leaves are pinnately compound, fern like, and triangular.
Clasp stem.
– White flowers grow in loose, flat topped umbels.
• Japanese has 2 or more small bracts growing beneath each umbel.
Spreading lacks these bracts.
– Fruit are bristly. Initially are rosy or white-green. They brown
as they mature.

52. Poison hemlock (Conium maculatum)
Courtney LeClair, WI DNR Courtney LeClair, WI DNR
Merel Black

53. Poison hemlock
(Conium maculatum)
• NR 40 Status – Prohibited/Restricted.
• Areas Invaded – Moist sites (prairie, pasture,
ROWs).
• Life History - Biennial.
• Key ID
– Stems are stout, hairless, hollow, ridged. Lower stem and
branches have distinctive reddish-purple markings.
– Leaves triangular, alternate, pinnately compound 3-4
times, shiny, hairless, parsley like.
– When crushed, emit a musty odor reminiscent of mice.
– Flowers in white umbels.

54. Wild chervil (Anthriscus sylvestris)
Robert Vidéki, Doronicum Kft., Bugwood.org
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Robert Vidéki, Doronicum Kft., Bugwood.org
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org

55. Wild chervil
(Anthriscus sylvestris)
• NR 40 Status – Prohibited/Restricted.
• Areas Invaded – Open woods, pastures, ROWs.
• Life History – Monocarpic perennial.
• Key ID
– Mature plants 1-5’, stem is branched, hollow, grooved, and
hairy with a fringe of hairs around lower nodes.
– Leaves pinnately compound, alternate, fern-like, triangular,
and usually hairy on the underside especially along the veins.
• Leaflets are pinnately divided and clasp the stem.
• Petioles grooved on upper surface.
– White flowers in flat umbels. Bloom very early in late spring.

56. Black Swallow-wort (Vincetoxicum nigrum)
syn. Cyanchum nigrum, C. loviseae
Related Invader: V. Rossicum

57. Black swallow-wort
• Herbaceous perennial
vine
• Invades
– riparian habitats
– grasslands

58. Black Swallow-
wort
• Leaves: simple, opposite
(3” long)
• Stems: 2-6 ft in height
• Flowers: 5 purple-black
petals with yellow center
• Fruit: slender pods 1.5-
2.5” long