Montana Pesticide Education Program http://mtpesticides.org

1. Montana Pesticide Education Programhttp://mtpesticides.org Residential Weed Management

2. What is considered a weed? • Any plant growing where it is not wanted. • Obnoxious Weeds • Toxic Weeds • Invasive and Noxious weeds are the most troublesome. • Rapidly dominate the site • Very difficult to control

3. Weeds are Indicators of Site Conditions • Salty Soils • Shepherds Purse, Russian Thistle • Acid soils – Very Acid Soils • Horsetail – Hawkweed & Knapweed • Badly drained soils • Horsetail • Deep shade • Ground ivy, chickweed

4. Noxious Weeds in Montana • Landowners are responsible for controlling the spread noxious weeds on their property • Cat 1 = established & widespread • Cat 2 = recently introduced and rapidly spreading • Cat 3 = Not yet detected or in few locations Category 2 • Category 1

5. Noxious Weeds in Montana Category 3

6. Weed Management Prevention is the most effective practice of all! • Buy clean seed for wildflowers or lawns; don’t plant weeds! • Clean yard equipment before using it in another area • Get weeds along streams under control • Use mulch materials or weed mats • Pull weeds early – before they go to seed!

7. Control Methods Mechanical • Mowing, hand pulling, burning, solarizing Cultural • Shading, site preparation, plant appropriate competitive vegetation Biological • Parasites, predators, and pathogens; typically a slow process – not for urban Chemical • Repeated application • Plants must be growing • USE ACCORDING TO LABEL

8. Chemical Control Weed Biology/Life Cycles Exploit Weed Weaknesses

9. Monocots: parallel leaf veins, growth points at/below soil level Grasses • Grass family • Cheatgrass, quackgrass • Sedge family • Nutsedge • Lily family • Wild onion, death camas

10. Dicots: net-like leaf veins, diverse growing points Broadleaf • Composite family • Dandelions, thistles, knapweed • Mustard family • Shepherd's purse, lambsquarter, whitetop • Carrot family • Hemlock Many others

11. 1. Seedling Tender, vulnerable 2. Vegetative Great uptake of water and nutrients 3. Seed production Reduced uptake, energy directed to flowers, fruit 4. Maturity Little uptake or energy production Stages of Weed Development

12. Annual weeds: live one year • Summer annuals: seed & die by winter. • Pigweed, lambsquarter, black medic • Winter annuals: germinate in late summer, overwinter, produce seed, die the next season. • Chickweed, curly dock, cheatgrass, black medic

13. vegetative growth first year (Rosette) • mature, seed and die in second year Biennial weeds: broadleaf plants with a 2-year life cycle • Houndstongue, mullein, burdock, bull thistle

14. Perennial weeds: live 3 or more years • most persistent • difficult to control • propagules • rhizomes, stolons, bulbs, tubers • wide range of dicots and monocots

15. Managing Landscape Weeds • Maintain competition – grazing management • Prevent seed production • Prevent seed germination • Limit emerged weeds early • Limit susceptible stages of mature weeds.

16. Chemical designed to control weeds. Plant, soil and weather conditions influence herbicidal activity.

17. Contact Systemic Herbicide Characteristics

18. Non Persistent Persistent Herbicide Characteristics

19. Non Selective Selective Herbicide Characteristics

20. Herbicide Characteristics • Application in relation to plant development • Pre-plant • Before crop is planted • Pre-emergent • Before weeds emerge • Post emergent • After weeds emerge

21. Herbicides and Plant Characteristics • Growing points • Leaf shape and orientation • Wax and cuticle

22. Herbicides and Plant Characteristics • Leaf hairs • Deactivation • Life cycle stage

23. Herbicide Effectiveness

24. Climatic Factors • Relative humidity • Light • Precipitation • Temperature

25. Bull Thistle (Cirsium vulgare) • Biennial • 2-5 feet tall • Flowers purple July-September • Reproduces by seed • Seed can be viable for 10 years Control: • hand pull • cut or mow before going to seed • herbicides? When?

26. Canada Thistle (Cirsium arvense) • Perennial • Flowers light pink-purple • Grows 1-4 feet tall • Has deep horizontal roots • Reproduces through creeping roots, some seed Control: • pull by hand (small plants) • apply herbicides; spot-spraying young plants is very effective

27. Poison Hemlock (Conium maculatum) • Biennial • Grows to 10 feet tall • Tiny white flowers & purple-mottled stems • All parts of plant are highly poisonous (if eaten) • Reproduces by seed Control: • hand pull or dig* (small plants) • apply herbicides in early spring or late fall *be sure to wear gloves & properly dispose of all plant material

28. Purple Loosestrife (Lythrum salicaria) • Perennial • Flowers purple on spikes • Stems are square; plant can be 6-8 feet in height • Reproduces by seed and roots Control: • cut, dig, or hand pull (small plants) • cut and remove the flowering spikes to prevent new seedlings • apply herbicides when actively growing at full to late flowering

29. Weed treatment in riparian areas • Select the most effective treatment methods for the site • If herbicides are used, be sure the label allows application adjacent to or in the water • Consider wipe application or hand removal

30. Animals & kids Drift Non-target vegetation Concerns over chemical use Movement of contaminated soil and vegetation Sensitive areas Herbicides in a Residential Setting Where is this water going?

31. Skid Mount Hose End ATV & Lawn Tractor BackpackHand Held Sprayers For Urban/Residential Use Up to 1 acre > 1 acre depending on tank size & GPA Spot Treatment < 1/10th acre

32. Prevent Drift Calibrate Your Sprayer Add the right amount General Precautions

33. UseCommonSense

34. 1.30% Dicamba 3.05% 2,4-D10.6% MCPP 8.0% Triclopyr What To Use

35. Now what? • Inventory the plants on your property • Identify invasive plants and weeds • Do you have a weed problem? Why? • What can you change about the way you manage your property to decrease the weed population?

36. Then... • Determine appropriate controls and your plans for the site and start working • Monitor for invasive plants • Plant native plants in your yard after the weeds are under control • Share this information with others