MANAGING WEEDS ON DISTURBED SLOPES. Susan Donaldson

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1 MANAGING WEEDS ON DISTURBED SLOPES Susan Donaldson

2 What we ll cover Legal responsibilities Avoiding spread of existing weeds Annual and biennial weeds and their management Perennial weeds and their management Invasive ornamentals to avoid

3 NRS 555 Places responsibility for control of noxious weeds on the landowner or occupier/manager Applies to both public and private lands 47 legally noxious weeds list at NAC 555 Failure to take action can result in an abatement and a lien placed on the property Administered by Nevada Dept. of Agriculture

4 Other legal requirements Nuisance ordinances (Washoe County example): Debris, refuse, rubbish. Material that is discarded, worn out or cast off without regard to value; and is of a nondecaying nature, or is capable of decomposition to a putrid state, or is of solid or semi-solid wastes. Examples are: animal carcasses; accumulation of excrement; leaves; trimmings from brush, lawns, trees, gardens or shrubbery; WEEDS; dead trees and branches; piles of earth mixed with any of the matter set forth in this definition; manure; paper; trash; cardboard; metal; wood; glass; crockery; bedding; scrap; appliances; furniture; equipment; parts; junk vehicles; construction waste. Wildland fire hazards

5 Avoiding the spread of weeds Learn to identify invasive AND desirable plants Control weeds on the site before disturbing the soil Wherever possible, retain existing vegetation and topsoil Create weed-free equipment staging areas

6 Avoiding the spread of weeds Clean equipment before leaving an infested site Use weed-free fill materials, including seed Revegetate disturbed soils with competitive vegetation Monitor for presence of weeds on a regular basis

7 Mulch and fill materials Dept. of Agriculture has a certification program for forage and gravel pits Beware of contaminated fill materials

8 Annual and biennial weeds Often arise from the existing seed bank Take advantage of disturbed soil Generally the first thing growing on a newly exposed site Reproduce from seed only

9 Annual and biennial weeds: cheatgrass

10 Annual and biennial weeds: flixweed

11 Annual and biennial weeds: tumble mustard

12 Annual and biennial weeds: Russian thistle

13 Annual and biennial weeds: kochia

14 Annual and biennial weeds: redstem filaree

15 Annual and biennial weeds: foxtails

16 Annual and biennial weeds: musk thistle

17 Control of annual and biennial weeds Prevent the formation of seeds Cut, mow, dig, pull, etc. Timing is important Herbicides are available Mulching can help with some weed species Consider preemergence herbicides to manage the seedbank if reseeding is not planned

18 Perennial weeds May have been on the site prior to disturbance May be introduced with fill materials or on equipment Much more difficult to control Must control seeds and kill the roots of the plants

19 Perennial weeds: perennial pepperweed

20 Perennial weeds: hoary cress

21 Perennial weeds: field bindweed

22 Perennial weeds: foxtail barley

23 Controlling perennial weeds Identify the species Does it spread by root fragments? If so, herbicides may provide the best control. Consider safety, residues, cost, effectiveness Control perennial weeds prior to earth-moving or replanting If area is revegetated with grasses, you ll be able to go in later with a broadleaf-specific herbicide

24 Using herbicides Selective vs. nonselective Residues and half-lives Cost and effectiveness Licensing requirements

25 Chemical comparison Chemical Selectivity Residual Effects Waterlabeled available 2,4-D Broadleaf Short Yes Glyphosate Non-selective Short Yes Arsenal Non-selective Very long Yes Garlon Broadleaf/ woody Short Yes Telar Broadleaf Long No Escort Broadleaf Long No Plateau Non-selective Moderate to long No

26 Preemergence herbicides will interfere with reseeding Chemical Dichlobenil Sample Brand Names Barrier, Casoron Field Half-life 60 days 6 months Low Oryzalin Surflan days Limited Pendimethalin Trifluralin Pendulum, Corral Preen, Treflan days (Reapply in 5 8 weeks) days Leaching potential Negligible Low to negligible

27 Application methods Spraying spot vs. boom Wiping Dip & clip

28 Invasive ornamentals to avoid: Green fountaingrass

29 Invasive ornamentals to avoid: Dalmatian toadflax

30 Invasive ornamentals to avoid: Yellow toadflax

31 Invasive ornamentals to avoid: Purple loosestrife

32 Remember: Identify weeds on the site BEFORE doing earthmoving Avoid contaminated fill, mulch, equipment, etc. Design a weed management plan that allows you to continue treatment during reveg Minimize bare ground Plan and budget for regular monitoring and retreatment