The Virtual WeedPatch

Weed Identification: Seedlings

Weed seedling identification is both the most important time to ID weeds to aid management decisions, as well as the most difficult time in a weed's life cycle to make that ID: they are small and few features are apparent.

One good way to learn weed seedlings is by the order in which they emerge in crop fields in the spring.

Proceed through each of the weed species below:

Composite (Compositae) Family

dandelion (Taraxacum officinale) Perennial
common cocklebur (Xanthium strumarium) Summer annual

Ragweed species-group:
-common ragweed (Ambrosia artimeisiifolia) Summer annual
-giant ragweed (Ambrosia trif

Thistle species-group:
-Canada thistle (Circium arvense) Perennial
-biennial thistles:
--musk thistle
--bull thistle (Circium vulgare) biennial

Dogbane ( ) Family

hemp dogbane

Grass (Graminaceae; Poaceae) Family

quackgrass (Elytrigia repens ) Perennial

Foxtail species-group:
-bristly foxtail (Setaria verticillata) summer annual
-green foxtail (Setaria viridis) summer annual
-giant foxtail (Setaria faberi) summer annual
-knotroot foxtail (Setaria geniculata) summer annual
-yellow foxtail (Setaria glauca) summer annual

Panicum species-group:
-wild proso millet (Panicum mileaceum) summer annual
-fall panicum

Crabgrass species-group:
-large crabgrass (Digitaria sanguinalis) summer annual
-smooth crabgrass (Digitaria ischaemum) summer annual

Sorghum species-group:

woolly cupgrass (Eriochloa villosa) summer annual

Lambsquarters (Chenopodiaceae) Family

common lambsquarters (Chenopodium album) Summer annual

Mallow (Malvaceae) Family

velvetleaf (Abutilon theophrasti) Summer annual

The Milkweed (Asclepiadaceae) Family

common milkweed

Mustard (Cruciferea) Family

field pennycress (Thlaspi arvense) Winter annual
shepard's purse (Capsella bursa-pastoris) Annual/Winter annual
wild mustard (Sinapis arvensis) annual/winter annual

Nightshade ( ) Family


Pigweed (Amaranthaceae) Family

The pigweed species-group

Smartweed (Polygoneaceae) Family

Knotweed species-group:
-prostrate knotweed (Polygonum aviculare) Summer annual
-erect knotweed (Polygonum erectum) summer annual

Smartweed species-group:
-Pennsylvania smartweed (Polygonum Pensylvanicum) summer annual
-Ladysthumb (Polygonum persicaria) summer annual