University of Maryland Extension

Weed of the Week Index

Landscape and Nursery IPM Reports:

Weeds for 2011-2019:

Algae, filamentous15Aug14
Amaranth, palmer

17July07

15May 01
11Jun24

Amaranth, spiny11Jun03
Automation and weed control12Sep07
Bamboo14May16
Barberry, Japanese14Jun06
Bedstraw, catchweed19Jun07
13May24
Beefsteak plant (Perilla frutescens)19Nov01
15Jul24
Beggartick, nodding13Aug02
Bermudagrass15Jul17
Bittercress, hairy

19Apr05
18Apr20

14Sep05,
12Oct05
, 12Mar16

Bittersweet, Oriental/Asiatic

15Jul10

Bluegrass, annual and roughstalk

19May10

18Apr27
17Apr07
15Apr24
14May02

14Apr18
12Apr06

Bluegrass, roughstalk13May03
British yellowhead (meadow fleabane)12Jul13
Broadleaf weed control alternatives13Oct25, 13Oct18, 13Sep20
Broomsedge17Aug25
Brunnera macrophylla 'Dawson's White'16Oct14
Burcucumber16Oct07
11Jul01
Burnweed, American18Sep14
Buttercup, bulbosus (Ranunculus bulbosus)16May20
14May30
Buttonweed, Virginia12Oct05
Canarygrass, reed12Jun22
Carpetgrass, small (Arthraxon hispidus)19Jul12
13Jul19
Cat's ear, common (false dandelion)12Jul06
Chickory (Cichoriium intybus)16Oct21
Chickweed, common16Apr15
Chinese yam (Dioscorea batatas)13May31
Cinquefoil, common14Oct24
Cinquefoil, sulfur12May11
Clematis terniflora11Oct21
Clover, white12Jun01, 12May25 (a lot in nurseries this year)
11Sep30
Cocklebur, common13Oct18
Crabgrass16Mar18 (early spring control)
13Apr19
12Mar09
(Jeffrey Derr article)
11Mar18 (focus on control)
Crow-dipper (Pinellia ternata)17May19
Daisy, fleabane14Oct03
Dayflower, Asiatic or common14Jul11
Deadnettle, purple19Mar29
16Apr22

12Apr13
Deadnettle, white spotted (Lamium maculatum)16Apr08
Dock, broadleaf13Apr12
Dodder19Jul26
15Jul31

13Jun21
11Aug26
Dogbane, hemp12Aug03
Dollar weed13Oct11
Drift issues13May17
Eastern black nightshade17Jul21
False green kyllinga17Jul14
False (also fool's) parsley (Aethusa cynapium)16May27
Fescue, meadow11May06
Foxtail, giant19Sep26
13Sep06
12Oct19
Geranium, Carolina

17Apr28

16Jun10
14Jun27

Goat's beard (Tragopogon dubius)

18Jul13

16Jul01

Goutweed (Aegopodium podagraria)

18May11

15Jun05

Greenbrier (Smilax spp.)15Oct16
Ground ivy (Glechoma microcarpa)19Jul19
Groundsel, common19Jun28
13Jul05
Hemlock, poison13Jun14
Hemp dogbane18Aug24
Herbicide use and rainscapes14Sep12
Herbicides: Understanding why they work14Apr04
Hog peanut16Sep16
Hogweed, giant

18Jun22

17Aug1817Jun09

13Jun28
12Jun08

Horsenettle

19Jun14

17Jun16
13Jul26

Indian mock strawberry (Duchesnea indica)15Oct09
Invasive plants - New MDA Tier 1 and Tier 2 plants16Apr29
Ironweed, New York18Oct05
Italian arum17Mar17
Japanese hops (Humulus japonicas)18Jul06
Jewelweed (Impatiens capensis), native, but reseeds well and can be a problem in some situations16Jul22
Johnsongrass

19Oct18
18Aug17
11Jul29

Joint-head grass (Arthraxon hispidus)15Oct01
Knapweed, spotted11Apr08
Knotweed, Japanese19Aug23
16Jun17

15May08

13Aug30
Knotweed, prostrate11Jun10
Kyllinga, green

18Nov0218Sep21

Lady's thumb

18Jun15

17May26

Lambsquarters13Sep20
Lespedeza, Chinese11Oct07
Lespedeza, common (Kummerowia striata (syn. Lespedeza striata)

19Aug30
16Oct28

14Jul03

12Aug31

Lesser celandine

19Apr26
18Apr06

17Mar24
16Apr01, 16Mar18 (sighting for report)
14Apr11

13Mar22
11Apr15

Lesser-seeded bittercress13Mar29
Lettuce, prickly (Latuca scariola)

18Aug31

15Jun26

Lettuce, willow leaf (Lactuca saligna)15May29
Marestail

17Jun30

13Jul12

Medic, black14Oct17
Mile-a-minute weed16Aug12
13Jul05
, 13Jun28
Morning glory, ivyleaf

18Sep07

12Sep14

Morning glory, tall19Sep20
14Aug22
Mugwort17Jul28
Mulberry tree14Aug15
Mulberry weed (aka hairy crabweed)19Aug09
13Aug23
11Jul08
Mullein, common12Aug10
Mustard, blue13Apr05
11Apr15
Mustard, garlic

19May03
18May18

15Jun12

Nettle, European stinging

18May04

12Aug24

Nightshade, bittersweet (Solanum dulcamara)

18Jun01

16Jul15

Nimblewill (Muhlenbergia shreberi)15Sep04
Nutsedge, yellow

18May25

16Sep23 (photo of nutlets)
16Jul08

15Mar20
(control update)
14Aug08

Panicum, fall

19Oct25

18Aug17
16Oct14, 16Aug26
11Sep23

Parsnip, wild12Mar09
Pear, Bradford19Apr12
Pennycress, thoroughwort11May13
Phyllanthus, long-stalked15Oct30
Plantain, broadleaf14Jun13
Pokeweed

17Aug04

14Aug01

Poison hemlock

18Jun22

Porcelainberry14Sep12
Prickly lettuce19May24
11Apr22
Prostrate spurge17Sep15
Purple deadnettle (Lamium purpureum)17Mar31
Purslane, common14Sep25
Queen Anne's Lace (Daucus carota)

18Jun22

15Sep25

Radish, wild11May27
Ragweed, common

17Oct13

11Sep02

Ragweed, giant12Jul20
Ragworm13Apr26
Ravenna-grass11Oct14
Redstem filaree11Sep09
Rose, multiflora18Oct26
Salsify (or goat's beard)12Jun01
Sandbur (Cenchrus)15Sep18
Shepherd's purse (Capsella bursa-pastoris)19May17
16Apr22
Smartweed, Pennsylvania12Jun15
Sorrel, red12Sep07
Sowthistle, common11Apr29
Sowthistle, spiny12May25
Speedwell, common (Veronica officinalis)17Apr14
Speedwell, Persian (Veronica persica)17Apr21
Spurge, Japanese19Apr12
Spurge, spotted16Aug19
14Jul18
Star-of-Bethlehem (Ornithogalum umbellatum)

18Apr13

15May22

Stiltgrass, Japanese19Aug02
12Apr20

11Oct07 (fungus found that infects this weed)
Teasel, common11Aug05
Thistle, Canada

17May12

16Sep30 (infected by bacteria)
13May10
11Apr01

Thistle, nodding15Aug21
Thistle, tall (Cirsium altissimum)16Jun03
Thoroughwort pennycress17Jun23
Timothy (Phleum pretense)16May13
Tree of heaven (Ailanthus altissima)

18Jul27

15Jul02

Velvetleaf11Jul22
Violet, field12Mar30
Violet, wild13Sep27
Virginia buttonweed11Sep16
Virginia creeper

18Jul20

14May23

Weed control and heavy rains15Jul02
Weed control challenges: timing, soil moisture16Sep02
15Aug07
Weed control problems in turf13Aug09
Weed control: management practices19Sep06 (in turf)
15Oct23
Weed control: soil temperatures16Mar25
Weed control review for fall germinating weeds15Aug14
Weeds in perennial beds13Aug30
Weed management in spring14Mar28
Wild violets (Viola pratincola)16May06
Wineberry (Rubus phoenicolasius)19Jun21
16Nov04

12Jul27
Witchgrass (Panicum capillare)16Jul29
Woodsorrel, yellow19Oct04
14Sep19
Yarrow, common17Aug11
Yellow archangel11Oct28
Yellow foxtail17Sep29
Yellow rocket12Nov02
Yellowcress, marsh15Jun19
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