Weed Control in Homeowner Ornamentals

1. Weed Control in Homeowner Ornamentals Tim R. Murphy The University of Georgia Landscape

4. Ornamental Weed Control Options • Hand-removal, hoeing • Mulches • Landscape fabrics • Herbicides

5. #1 Home Owner Question What can I spray on *&^#@!? weed to kill it and how much do I need??

6. Mechanical Control Fabric Mulches • Plastic or fabric thickness affects the degree of weed suppression. • Clear and colored plastics that allow light penetration produce high temperatures in the upper surface. • This build up of heat, solarization, kills germinating weed seeds.

7. Landscape Fabrics • Expensive • Limited commercial use • Very good option for homeowners • Use high quality, non-woven, fused fabric • Properly mulch

8. Organic Mulches • Straw, wood chips, pine straw, sawdust, newsprint, and other organic materials. • These mulches also shade and physically hinder germinatingseedlings

9. Organic Mulches • Coarse texture better than fine • Texture more important than type • 2 to 4 inch depth • Renew as needed • Nothing is permanent!

10. Mulches control most weeds expensive?? good use of “waste” handling is often materials a pain Conserves water Advantages Disadvantages

11. Mechanical Control Hand Pulling and Hoeing • Still used for weed control in high value crops • Best control with small weeds <4 inches • Must understand how the weeddevelops (annuals vs. perennials)

12. Hand Weed Control keeps you in shape repetition is a must environmentally friendly can stimulate germination controls most weeds must be timely Inexpensive (if done by self Advantages Disadvantages

13. Mechanical Control Tillage • Controls many weeds that have emerged • Incorporate fertilizers, lime • Prepares seed or plant beds

14. Tillage Practices control most weeds expensive?? quick and easy can’t get too close to crop – root pruning noise pollution Advantages Disadvantages

15. HERBICIDES

16. Ornamental – Homeowner Herbicides • Annual grass control available • Preemergence and postemergence • Pre and Post broadleaf weed control is difficult • Use post graminicides for perennial grass control • Vines, woody plant control is exceeding difficult

18. Ornamental Preemergence Herbicides • Primarily dinitroanilines • Treflan, Surflan, Pendulum, Endurance, XL, Team • Preen • Preen-N-Green • Snapshot - trifluralin + isoxaben

19. Ornamental Preemergence Herbicides • Products labeled for various species • Irrigate-in if possible (1/2 inch) within 7 days • Do not apply to wet foliage • Match weeds to specific products • Use fall + spring applications • Rotate products if possible

20. Homeowner - Selective POST Grass Control Herbicides • Sethoxydim - Vantage, Hi-Yield Poast • reseeding restriction: not listed • Fluazifop - Dexol Grassout Greenlight Bermudagrass Killer Ortho Grass-B-Gon - reseeding restriction: 2 months

21. Ornamentals – Post-Grass Control • Use on any non-grass ornamental • Trees, woodies, annuals, perennials • Includes liriope, hosta, iris, daylily • Don’t spray open blooms • No “nutgrass” control • Avoid applications on “scorchy-hot”, humid days

22. Integrated Weed Management Integrating preventive, mechanical (mulches, fabrics), cultural and chemical methods is usually the most effective method of managing weeds in ornamentals.

23. Florida betony

24. Florida Betony - Stachys floridana • Labitae (mint family) • “Rattlesnake weed” • perennial • reproduces primarily by tubers • opposite, serrated leaves • occurs in turf and ornamentals

25. Florida Betony Control • Roundup, Finale • Casoron applied in winter, very difficult to find, can be ordered at Southern States, commercial herbicide stores • Use landscape fabric in ornamentals

26. Bamboo • Phyllostachys aurea • Grass family • rhizomatous • rarely fruits • no wildlife value • full sun, partial shade • native to China

27. Bamboo Control • No herbicide is labeled for the control of bamboo.

28. Bamboo Control • Roundup Pro, 2% v/v, apply to regrowth 3 to 6 feet tall, repeat, not on label • Roundup Pro, 33% v/v, apply with gloved hand to husk stage, repeat, not on label • MSMA, 2% v/v, will “knock” leaves off, repeat • Mechanical barrier, 30 inches deep

29. Phyllanthus spp. - Biology • Summer annuals • Spurge family • Seeds require light • Tolerates full sun and moderate shade

30. Chamberbitter, niruri, gripeweed

31. Chamberbitter - Phyllanthus niruri • Euphorbiaceae (spurge family) • niruri, gripeweed, leafflower • summer annual, reproduces by seed • alternate leaves, numerous leaflets • inconspicuous flowers • stalkless green, round fruit • no milky juice

32. Longstalked Phyllanthus

33. Longstalked Phyllanthus (Phyllanthus tenellus) • Euphorbiaceae (spurge family) • summer annual, reproduces by seed • alternate leaves, numerous leaflets • inconspicuous flowers • stalked green, round fruit • no milky juice

34. Phyllanthus spp. - Control • Use mulch • Apply early spring

35. Phyllanthus spp. Preemergence Control • Ronstar (not labeled for use in home landscapes) • Rout (OHII - slightly less effective) • Surflan + Gallery (Snapshot TG - less effective) • Prodiamine (Factor, Endurance, Barricade) • Gallery

36. Phyllanthus spp. Postemergence Control • Roundup Pro • Finale • Reward LS

37. Phyllanthus spp. Ineffective Herbicides • Basagran T/O • Image • MSMA • Pennant • Pendimethalin • Balan

38. Isoxaben Products - Homeowners • PRE herbicide for control of annual broadleaf weeds • Primarily used in woody ornamentals • Gallery • Greenlight Portrait • Reseeding restrictions - 2 months

39. EPTC Products - Homeowners • PRE control of annual grass and broadleaf weeds • Woody ornamentals, some flowers, groundcovers • Preen for Groundcovers

40. Homeowner - Nutsedge Herbicides • Image – imazaquin • reseeding restriction: 6 weeks • Manage – halosulfuron -reseeding restriction: 4 weeks • Bentazon • Basagran T/O, Hi-Yield Basagran • reseeding restriction: 0 week

41. Sedge Herbicides -Ornamentals • Basagran T/O - yellow, annual sedges • Manage - yellow, purple, annual sedges • Image - yellow, purple, annual sedges • Pennant - yellow, annual sedges • Preemergence only • No homeowner package available

42. Basagran T/0 - Ornamentals • Directed spray around base of ornamentals • Over-the-Top • Hollies, ornamental cabbage, pachysandra • Liriope, impatiens, marigold • English ivy, petunia, ajuga • “Safer”option for yellow nutsedge than Roundup Pro

43. Manage - Ornamentals • Post-directed around woody ornamentals • New-transplants- wait 3 months • Do not use in annuals or herbaceous perennials • May be applied 4 weeks in advance of transplanting woody ornamentals

44. Image - Ornamentals • Over-the-top • Junipers, Burford hollies, Helleri holly, Indian hawthorne, • Liriope, mondograss, hostas, Red tip photinia • Pachysandra, Asiatic & Confederate jasmine • Do not apply over root zone of non-listed ornamentals • Azalea, ligustrum, viburnum, pieris, abelia are severely injured by Image

45. Dodder

46. Dodder - Cuscuta spp. • Convolvulaceae (morningglory family) • rootless, leafless parasitic annuals • “yellow spaghetti” • prolific seed producer • germinates early spring • 8 species known in Georgia • wide host range on broadleaf plants

47. Dodder Control - Ornamentals • Fumigate - Basamid • Casoron, Norosac - woody ornamentals, may be difficult to find • Dacthal - dropped by manufacturer • Kerb - woody ornamentals, Restricted Use Herbicide • Roundup, Finale