Compiled by Charles L. Mohler

Weed common name Weed scientific name Family Life history Seed weight (mg)1,2 Season of emergence Seedbank longevity3
Barnyardgrass Echinochloa crusgalli (L.) Beauv. Grass summer annual 1.7 spring to summer 3–8 yrs
Bedstraw, catchweed (cleavers) Galium aparine L. Madder summer or winter annual 7.2 fall, spring, winter 1–5 yrs
Bedstraw, smooth Galium mollugo L. Madder perennial 0.4–0.6, 0.7 seeds; early to late spring, fall in warm regions. Shoots: early spring usu. 3–12 mos
Bindweed, field Convolvulus arvensis L. Morningglory perennial spreading by deep, creeping fleshy roots 10 fall, spring >20 yrs
Bindweed, hedge Calystegia sepium (L.) R. Br. Morningglory perennial spreading by deep, creeping fleshy roots 40 spring, fall >20 yrs
Bluegrass, annual Poa annua L. Grass annual or short-lived perennial 0.26 spring, late summer to early fall up to 4 yrs
Buckwheat, wild Polygonum convolvulus L. Buckwheat summer annual 6 spring, some in summer and fall up to 5 yrs
Burcucumber Sicyos angulatus L. Cucurbit summer annual 81 mid spring to early summer NA
Campion, white Silene alba (Mill.) E.H.L. Krause Pink winter or summer annual, biennial or short-lived perennial 0.74 mid to late spring, late summer 5–20 yrs
Chamomile, corn Anthemis arvensis L. Lettuce annual or biennial 0.5, 1.2 fall, spring 5–20 yrs
Chamomile, mayweed Anthemis cotula L. Lettuce winter or summer annual 0.4 fall, spring >20 yrs
Chickweed, common Stellaria media (L.) Vill. Pink winter or summer annual 0.35, 0.67 fall, spring 20–60 yrs
Chickweed, mouseear Cerastium vulgatum L. Pink perennial 0.13 late summer to fall, spring NA
Cockle, corn Agrostemma githago L. Pink winter annual 12, 15 fall, spring usu. <3 mos
Cocklebur, common4 Xanthium strumarium L. Lettuce summer annual small, 39; large, 54 spring to summer up to 2.5 yrs
Copperleaf, Virginia Acalypha virginica L. Spurge summer annual 0.73 late spring NA
Crabgrass, large Digitaria sanguinalis (L.) Scop. Grass summer annual 0.52 spring several yrs
Dandelion Taraxacum officinale Weber in Wiggers Lettuce perennial 0.6 spring 1–5 yrs
Foxtail, giant Setaria faberi Herrm. Grass summer annual 1.3 late spring to midsummer <5 yrs
Foxtail, green Setaria viridis (L.) Beauv. Grass summer annual 11 throughout growing season up to 21 yrs
Foxtail, yellow Setaria glauca (L.) Beauv. Grass summer annual 2.5, 3.4 spring, some up to 13 yrs
Galinsoga, hairy Galinsoga ciliata (Raf.) Blake Lettuce summer annual 0.18 spring, also summer and fall a few yrs
Galinsoga, smallflower Galinsoga parviflora Cav. Lettuce summer annual 0.17 spring, also summer and fall a few yrs
Goosegrass Eleusine indica (L.) Gaertn. Grass summer annual 0.51 early to midsummer <5 yrs
Groundcherry, smooth Physalis subglabrata Mackenz. & Bush Nightshade perennial spreading by deep rhizomes 1.5 spring to summer NA
Groundsel, common Senecio vulgaris L. Lettuce summer or winter annual 0.18, 0.22 fall, spring, summer, winter 1–5 yrs
Henbit Lamium amplexicaule L. Mint winter annual 0.53 fall, spring >4 yrs
Horsenettle Solanum carolinense L. Nightshade perennial spreading by deep, creeping roots 1.1–1.9 spring up to 7 yrs
Horsetail, field Equisetum arvense L. Horsetail perennial spreading by rhizomes tiny spore spring spores short-lived
Jimsonweed Datura stramonium L. Nightshade summer annual 5.6, 7.8 spring >20 yrs
Johnsongrass Sorghum halpense (L.) Pers. Grass perennial spreading by shallow rhizomes 6.2 spring up to 7 yrs
Knotweed, prostrate Polygonum aviculare L. Buckwheat summer annual 1.7 spring NA
Kochia Kochia scoparia (L.) Schrad. Beet summer annual 0.54 spring <2 yrs
Lambsquarters, common Chenopodium album L. Beet summer annual 0.7 spring to summer >20 yrs
Lettuce, prickly Lactuca serriola L. Lettuce summer or winter annual or biennial 0.45 fall, spring 1–5 yrs
Mallow, Venice Hibiscus trionum L. Mallow summer annual 3.3 summer NA
Medic, black Medicago lupulina L. Legume winter or summer annual 1.2–2.5 fall, spring 1–5, 5–20 yrs
Milkweed, common Asclepias syriaca L. Milkweed perennial spreading by deep, creeping roots 0.43–0.73 spring up to 9 yrs
Millet, wild-proso Panicum miliaceum L. Grass summer annual 14 spring through summer >5 yrs
Morningglory, ivyleaf Ipomoea hederacea (L.) Jacq. Morningglory summer annual 30, 32, early summer prob. many yrs
Morningglory, pitted Ipomoea lacunosa L. Morningglory summer annual 27 early summer >39 yrs
Morningglory, tall Ipomoea purpurea (L.) Roth Morningglory summer annual 25 early summer prob. many yrs
Mustard, hedge Sisymbrium officinale (L.) Scop. Mustard winter or summer annual, rarely biennial 1.5 spring to summer >5 yrs
Mustard, wild Brassica kaber (DC.) L.C. Wheeler (= Sinapsis arvensis L.) Mustard summer or winter annual 1.6, 2.3 spring, late summer to early fall up to 60 yrs
Nightshade, eastern black Solanum ptycanthum Dun. Nightshade summer annual 0.43 spring to summer up to 39 yrs
Nutsedge, yellow Cyperus esculentus L. Sedge perennial with rhizomes and tubers 0.17 spring most tubers <2 yrs
Panicum, fall Panicum dichotomiflorum Michx. Grass summer annual 0.57 late spring to midsummer 10 yrs
Pennycress, field Thlaspi arvense L. Mustard winter or summer annual 1.25 fall, spring >20 yrs
Pepperweed, field Lepidium campestre (L.) R. Br. Mustard winter annual 1.9 late summer to early fall NA
Pepperweed, Virginia Lepidium virginicum L. Mustard winter or summer annual, occasionally biennial 0.35 late summer to early fall, some spring NA
Pigweed, Powell amaranth Amaranthus powellii S. Wats. Pigweed summer annual 0.51 mid spring NA
Pigweed, prostrate Amaranthus blitoides S. Wats. Pigweed summer annual 0.89 late spring to early summer NA
Pigweed, redroot Amaranthus retroflexus L. Pigweed summer annual 0.39 mid spring up to 20 yrs
Pigweed, smooth Amaranthus hybridus L. Pigweed summer annual 0.37 mid to late spring up to 40 yrs
Pigweed, tumble Amaranthus albus L. Pigweed summer annual 0.28 late spring to early summer, some through fall NA
Purslane, common Portulaca oleracea L. Purslane summer annual 0.13 summer >20 yrs
Quackgrass Elytrigia repens (L.) Nevski Grass perennial spreading by shallow rhizomes 2 spring, fall 5–20 yrs
Radish, wild Raphanus raphanistrum L. Mustard winter or summer annual 8 late summer to fall, early spring up to 20 yrs
Ragweed, common Ambrosia artemisiifolia L. Lettuce summer annual 3.2 early to late spring up to 40 yrs
Ragweed, giant Ambrosia trifida L. Lettuce summer annual 17, 31 early spring, diminishing through early summer 4–18% survive 1st yr
Rocket, yellow Barbarea vulgaris R. Br. Mustard biennial or short-lived perennial, occasionally a winter annual 0.5 fall, spring, winter 1–5 yrs
Ryegrass, Italian Lolium multiflorum Lam. Grass winter annual 2 spring, late summer to mid fall <4 yrs
Shattercane Sorghum bicolor (L.) Moench Grass summer annual 14 mid spring to early summer <13 yrs
Shepherd's purse Capsella bursapastoris (L.) Medicus Mustard summer or winter annual 0.1 fall, spring, summer, winter >20 yrs
Sida, prickly Sida spinosa L. Mallow summer annual 2.3 spring to midsummer up to 6 yrs
Smartweed, Pennsylvania Polygonum pensylvanicum L. Buckwheat summer annual 4.5, 6.5 spring to early summer up to 30 yrs
Sowthistle, annual Sonchus oleraceus L. Lettuce winter or summer annual 0.27, 0.34 fall, spring 5–20 yrs
Sowthistle, perennial Sonchus arvensis L. Lettuce perennial spreading by creeping roots 0.4–0.7 shoots: early spring seedlings: late spring to early summer <5 yrs
Speedwell, corn Veronica arvensis L. Snapdragon annual 0.1 fall, spring up to 20 yrs
Speedwell, Persian Veronica persica Snapdragon winter or summer annual 0.38, fall, spring, summer, winter up to 30 yrs
Speedwell, purslane Veronica peregrina L. Snapdragon annual 0.03 spring, fall NA
Thistle, Canada Cirsium arvense (L.) Scop. Lettuce perennial spreading by horizontal roots 1.2 spring, fall 5–20 yrs
Velvetleaf Abutilon theophrasti Medicus Mallow summer annual 7 late spring to early summer up to 50 yrs
Violet, field Viola arvensis Murr. Violet annual 0.2 fall, spring >5 yrs
Witchgrass Panicum capillare L. Grass summer annual 0.35 late spring to midsummer several decades
Woodsorrel, yellow Oxalis stricta L. Woodsorrel perennial with short, shallow rhizomes 0.13 spring to summer >5 yrs
Yellowcress, marsh Rorippa islandica (Oeder) Borbas Mustard annual, biennial, short-lived perennial (rarely) NA spring up to 10 yrs


1 For comparison, one lettuce seed weighs about 1 milligram.

2 Multiple numbers are weights from different populations, except for common cocklebur.

3 Data are maximum survival of seeds in soil, often based on undisturbed burial experiments. Seeds usually die off at a constant rate, so that most are gone much more quickly than the numbers indicate. Also, they die off more quickly in regularly tilled soil. NA=Information not available.

4 Common cocklebur has one large and one small seed in each capsule.


Compiled primarily from References 1, 7, 11, 12, 13, 15, 25, 32, 38, 49, 76, 77, 87, 88, 90, 91, 108, 109, 112, 116 and 117, and data of the author.