1. Weed Identification Made Easy
Chelan County Noxious Weed Department
Julie Sanderson, Field Supervisor

2. Many options for killing weeds
Weeds can be controlled with herbicides, with biological control agents such as insects or pathogens, with cultural methods such as grazing or changes in water or fertilizer treatments, and by mechanical methods such as hoeing, hand pulling or cultivation.

3. Always use Integrated Weed Management
Integrated Weed Management involves using any or all of the methods of weed control based on best management practices for the land that is infested with weeds. Control methods include prevention, mechanical control, cultural control, chemical control and biological control.

4. It’s The Law (RCW 17-10) Stand-Alone Or Combination Of These Methods:
Prevention
Mechanical
Biological
Chemical
Cultural
“Control” means
to prevent all
seed production
Washington State Law RCW makes it the land owners’ responsibility to control noxious weeds on their property. Any of these methods can be used, but they must result in control, defined as the prevention of seed production and spread of the weeds from the owners property.

5. Use the right chemical for the job
Before
After
If herbicide is part of your integrated weed management plan, it is important to know which plant you are spraying, and which herbicide will be effective for controlling it.
Bohemian knotweed

6. WEED IDENTIFICATION
The first step to integrated weed management is knowing which weed you are trying to control!
Begin your weed control plan by identifying all of the weeds that you are trying to control so that you know the names of the weeds that you are trying to control.

7. What’s in a name? Information!
Plant family, specific Latin name, common name
Life cycle – Is it annual, perennial, biennial?
Toxicity information – Can I touch it, what if my dog eats it? Is it allelopathic?
Herbicide use- Is it listed on the label, is there resistance?
Noxious weed status- Is it listed in my state or county?
(This one can be translated directly from the slide text)

8. Know your enemy! Why learn to identify weeds?
What information do you need?
Knowing the right name allows access to information about the specific plant that needs to be controlled.
How does the biology of the plant affect control options?
What is the most effective chemical for control?
Is the plant listed on the herbicide label?
Is there any herbicide resistance known for the plant?
(This one can be translated directly from the slide text)
Yellow starthistle
Centaurea solstitialis

9. Look alike weeds may require different control methods
What’s in a name?
Look alike weeds may require different control methods
Do you know which
name belongs to
each plant?
Yellow starthistle
Perennial sowthistle
Prickly lettuce
Rush skeletonweed
(This one can be translated directly from the slide text)

10. Look alike weeds may require different control methods
What’s in a name?
Look alike weeds may require different control methods
Yellow starthistle
Perennial sowthistle
Prickly lettuce
Rush skeletonweed
Yellow starthistle is a Class B Designate plant that is mandatory to control in Chelan County. It is an annual, produces abundant seed, and can be toxic to horses.

11. Look alike weeds may require different control methods
What’s in a name?
Look alike weeds may require different control methods
Yellow starthistle
Perennial sowthistle
Prickly lettuce
Rush skeletonweed
Perennial sowthistle is a Class C noxious weed, not selected for mandatory control in Chelan County, but which can become very invasive on some sites. It can be difficult to control because of the stout roots and rhizomes.

12. Look alike weeds may require different control methods
What’s in a name?
Look alike weeds may require different control methods
Yellow starthistle
Perennial sowthistle
Prickly lettuce
Rush skeletonweed
Prickly lettuce is an annual nuisance weed. It is not on the noxious weed list. It can be controlled by mowing, pulling, or with contact herbicides.

13. Look alike weeds may require different control methods
What’s in a name?
Look alike weeds may require different control methods
Yellow starthistle
Perennial sowthistle
Prickly lettuce
Rush skeletonweed
Rush skeletonweed is a Class B Designate noxious weed requiring mandatory control. It has deep perennial rhizomes, pulling and cutting can promote more rosettes to emerge and increase patch size. Persistent chemical control works best for this one.

14. The 8 Great Things to Notice About Plants
Plant Character Analysis
1. Plant Habit
2. Leaf Arrangement
3. Leaf Shape and Texture
4. Inflorescence Type
Flower structure
Fruit Type
Roots and underground structures
Other Observations
To learn to identify the weeds that you work with, it is important learn the plant characteristics, or “the 8 great things to notice about plants”. Looking at these characteristics is very useful when looking at plants that look alike.

15. 1. Plant Habit
This is one of the first things a person may notice about a plant. Habit is the general appearance, characteristic form or mode of growth of a plant. Simply stated it is how the whole plant looks when it is growing. For example a plant can be erect, meaning that the stems stand straight up. Or a plant can be creeping, the stems are flat on the ground.

16. 2. Leaf arrangement
Always look at how the leaves of the plant are arranged in relation to each other. They can be alternating step-like up the stem, or clustered at the base of the stem. Some plants have pairs of leaves attached on opposite sides of the stem at each node.

17. 3. Leaf shape and texture
Also pay close attention to the shape and texture of the leaf. There are many shapes possible, from long and narrow to almost round in outline. The texture could be waxy, smooth and glossy, or with various kinds of hair, from course and prickly to short and velvety.

18. 4. Inflorescence Type axillary raceme solitary panicle spike head
The inflorescence is the structure that contains the flowers. This picture uses circles to represent each flower. The arrangement of the flowers is characteristic for each species and many families. For example the umbel arrangement is found in the carrot family species such as poison hemlock. The head type of inflorescence is found in many weedy species including dandelion, ox-eye daisy and the knapweeds.
head
umbel
corymb
Illustrations by Suzanne McCullough from the Botany Handbook of Florida, 1965 ORH 89-3, Florida Department of Agriculture
And Consumer Services, and the Florida Federation of Garden Clubs, Inc.

19. 5. Flower Structure
The arrangement and number of flower parts are important characteristics to observe when trying to identify a plant. For example, plants in the mustard family usually have 4 petals, 4 sepals and 6 stamens.

20. 6. Fruit Types Legume Follicle
If a plant is already mature when you find it, you can look at the fruit and seeds. The fruit may be a dry capsule that splits open to shed seeds, or a fleshy berry. All plants in the pea family have a legume fruit, which splits open like a pea pod to shed the seeds.
Follicle
Illustrations by Suzanne McCullough from the Botany Handbook of Florida, 1965 ORH 89-3, Florida Department of Agriculture
And Consumer Services, and the Florida Federation of Garden Clubs, Inc.

21. 7. Roots and Underground structures
Rhizomes and Stolons
Fibrous
It is a good idea to dig up some plants to see the roots when you are trying to identify a plant. Most descriptions of plants will contain information about the roots. Knowing what kid of roots a weed has can be useful information when making a control plan.
Tap root
Illustrations by Suzanne McCullough from the Botany Handbook of Florida, 1965 ORH 89-3, Florida Department of Agriculture
And Consumer Services, and the Florida Federation of Garden Clubs, Inc.

22. 8. Other Observations Unusual odor Sticky texture
Plant juice – milky, sticky, viscous, watery
Overall color – bright green, gray, yellow
Bracts, spines, thorns or hairs
Associated insects
Some other characteristics can be useful for plant identification, so make a note about odors, textures and color as well as any unusual thorns, spines or hairs. You may notice many insects all of the same type on a plant, these could be biological control agents.

23. And how to tell them apart
More look alike weeds
And how to tell them apart
The following slides show some weeds that look similar and show what characteristics can be useful to identify each of them.

24. Knapweeds, which one???
Four different species of knapweeds that are common in Chelan County. How can we tell which is which?

25. Look at the bracts Russian knapweed Diffuse knapweed
All class B noxious weeds
An easy character to look at when the plants are flowering is the structure of the flower head bracts. For example, the diffuse knapweed bracts have a very sharp point on the end. Russian knapweed has a soft papery bract. Meadow and spotted knapweed bracts differ in the number, color and size of the appendages on the bracts.
Meadow knapweed
Spotted knapweed

26. Big green brushy looking stuff?
Kochia - Class B
Pigweeds (redroot and white)
Lambsquarters
Russian thistle
Several of our common weeds mature and have a generally round an highly branched or ‘bushy’ form. To tell these apart you may have to look at the flowers and the leaves.

27. Look at the flowers kochia pigweed lambsquarters Russian thistle
The flowers on all four of these plants are small, greenish and inconspicuous, but if you look at them closely, you can see that the flower structure is distinctly different for each one.
lambsquarters
Russian thistle

28. Tumbleweeds – ready to roll.
The rounded, highly branched habit of some weeds makes it easy for them to be blown long distances by the wind after the plant matures and the seeds are ready to drop off.

29. Tumble pigweed (Amaranthus albus)
The term tumbleweed refers to any of several species that disperse seeds by tumbling:
Russian thistle
Diffuse knapweed
Kochia
Tumble pigweed (Amaranthus albus)
(This one can be translated directly from the slide text)

30. So many thistles, so little time…
Canada thistle**
Bull thistle**
Musk thistle**
Scotch thistle** **most common thistles here
Plumeless thistle
Slenderflower thistle
Italian thistle
Milk thistle
Native thistle (Cirsium undulatum)**
Many people are concerned about controlling thistles. There are eight different species of thistles on the noxious weed list, and a few native thistles that occur in our area as well.

31. Most common thistles Look at a combination of characters:
Here are four of the most common thistles in this area. While many people know a thistle when they see one, they may not know which thistle it is. By looking at a combination of characters, the flowers, stems and leaf surfaces, you can learn to distinguish the different thistle species.
Canada thistle
Bull thistle
Musk thistle
Scotch thistle
Look at a combination of characters:
flowers, stems, and leaf surfaces.

32. Canada thistle - Class C
Canada thistle is a Class C noxious weed in Washington State. The combination of characters listed here can help you to identify this plant
Small flowers <1”, spineless bracts
Smooth spineless stem
Green glossy leaves, not hairy, very spiny along margins
Class C noxious weed

33. Bull thistle Larger flowers 1.5-2” with long spiny bracts
Bull thistle is also a Class C noxious weed. Notice that the flower head is quite a bit larger, and there are fewer heads on each branch. The hairy leaf surface makes this plant easy to identify even in the rosette stage.
Larger flowers 1.5-2” with long spiny bracts
Stem spiny, somewhat winged
Leaf surface hairy
Class C noxious weed

34. Musk thistle Flowers large 1.5-3”, broad spiny bracts,
Musk thistle has the largest head of our weedy thistles. Notice the broad bracts under the flowers, resembling a small artichoke. The leaves are green and smooth, like Canada thistle, but the root is a strong tap root in musk thistle, which is different from the perennial rhizomes in Canada thistle.
Flowers large 1.5-3”, broad spiny bracts,
“artichoke –like’
Stems spiny somewhat winged
Leaves green, not hairy
Class B noxious weed

35. Scotch thistle – Class B
Steve Dewey, Utah State University, Bugwood.org
Bonnie Million, National Park Service, Bugwood.org
Scotch thistle is a Class B noxious weed. It is a high priority to control this thistle in most of the state. Notice the strongly winged and spiny stems. Also the greyish green color is characteristic of this species.
Flowers 1 -2”, narrow spiny bracts
Stem spiny, strongly winged
Leaves gray-green, with fine wooly hair
Class B noxious weed

36. Daisies, we love them, we love them not.
Scentless mayweed
Oxeye daisy
Daisies, we love them, we love them not.
There are several weedy daisies that look very similar. But by looking closely at some of the leaf characteristics, you can tell them apart.
Stinking mayweed
English daisy

37. Daisies with finely divided leaves
Stinking mayweed
Scentless mayweed – Class C
Stinking mayweed has leaves that are finely divided with short curved segments. Scentless mayweed, which is a Class C noxious weed also has finely divided leaves, but the segments are long, narrow and straight.

38. Daisies with oval, toothed basal leaves
English daisy
Oxeye daisy – Class C
Both of these daisies have oval leaves. Oxeye daisy, a Class C noxious weed has rounded teeth along the leaf margins, while English daisy has smoother leaf margins with only a few shallow lobes or teeth.

39. Other Ways to Identify Weeds
Use reference books
Use online resources
Ask someone who knows weeds
This has been a brief introduction to the use of plant characteristics for identification of weedy species. There is a lot more information available on this topic in libraries and on the internet. Also, remember that it can be very useful to talk to other people who know plants in your area.

40. Weed Identification Made Easy???
(Well…a little easier, I hope)
Chelan County Noxious Weed Department
Julie Sanderson, Field Supervisor

41. Thanks to Bugwood.org for the use of photos and figures:
Image Number
Citaton
Julia Scher, USDA APHIS PPQ, Bugwood.org
USDA PLANTS Database, USDA NRCS PLANTS Database, Bugwood.org
Cindy Roche, Bugwood.org
Forest & Kim Starr, Starr Environmental, Bugwood.org
Joseph M. DiTomaso, University of California - Davis, Bugwood.org
John M. Randall, The Nature Conservancy, Bugwood.org
Richard Old, XID Services, Inc., Bugwood.org
Robert Vidéki, Doronicum Kft., Bugwood.org
Bonnie Million, National Park Service, Bugwood.org
24090
Sara Rosenthal, USDA Agricultural Research Service, Bugwood.org
Steve Dewey, Utah State University, Bugwood.org
21042
Eric Coombs, Oregon Department of Agriculture, Bugwood.org
Mary Ellen (Mel) Harte, Bugwood.org
Peggy Greb, USDA Agricultural Research Service, Bugwood.org
Dave Powell, USDA Forest Service, Bugwood.org
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
580002
Loke T. Kok, Virginia Polytechnic Institute and State University, Bugwood.org
Dan Tenaglia, Missouriplants.com, Bugwood.org
Ricky Layson, Ricky Layson Photography, Bugwood.org
580013
Montana Statewide Noxious Weed Awareness and Education Program Archive, Montana State University, Bugwood.org
Caleb Slemmons, University of Maine, Bugwood.org
Michael Shephard, USDA Forest Service, Bugwood.org