Early Spring Weeds in No-Till Fields

Warmer temperatures and rainfall occurring across much of the state are causing weeds to flourish. Many of these weeds started their growth last fall and overwintered as a rosette. However, there will be some that germinate from seed this spring. These weeds will cause problems with planting in no-till settings if they are not adequately controlled. Before burndown herbicide programs are considered, it is best to know what weeds you are targeting to best determine what products to use and when to apply them for optimum performance. Therefore, scouting fields now can be worthwhile. Below are several common weed species that are present in fields now. Depending upon your location in the state and accumulated heat units, some of these species may have flower structures and have more advanced growth. Once you correctly identify the weeds, use resources such as the Penn State Agronomy Guide for herbicide suggestions.

(The following images were taken by D. Lingenfelter, Penn State Weed Science)

Aster family: Common spring species in this family include marestail/horseweed, fleabane, common groundsel, corn chamomile, dandelion, common burdock, thistles, and prickly lettuce.

marestail/horseweed (Conyza canadensis; annual)

fleabane (Erigeron spp.; annual)

common groundsel (Senecio vulgaris; annual)

common burdock (Arctium minus; biennial)

dandelion (Taraxacum officinale; perennial)

Mustard family: Typical early-season species in this family include field pennycress, shepherd's purse, hairy bittercress, pepperweed, yellow rocket, birds-rape mustard, and Whitlow grass.

field pennycress (Thlaspi arvense; annual)

shepherd’s-purse (Capsella bursa-pastoris; annual)

Yellow rocket (Barbarea vulgaris; annual)

hairy bittercress (Cardamine hirusta; annual)

Whitlow grass (Draba verna; annual, two samples on left); vs. marestail/horseweed on right

Pink family: Common chickweed and mouseear chickweed are the most common species in this group but others include white and bladder campion and knawel.

common chickweed (Stellaria media; annual)

mouseear chickweed (Cerastium vulgatum; perennial)

Mint family: Henbit and purple deadnettle are very common in early spring. Ground ivy is another species in this family but is most prevalent in turf and landscape settings.

henbit (Lamium amplexicaule; annual)

purple deadnettle (Lamium purpureum; annual)

henbit (left) and purple deadnettle inflorescence

Figwort family: Speedwell populations are common this time of year. Corn speedwell is frequently found in no-till settings, however, there are several different speedwell species, and they can be difficult to distinguish – some are annuals and other perennials.

corn speedwell (Veronica arvensis.; annual)

There are miscellaneous other species that can be found in no-till settings prior to burndown such as dock, poison hemlock, bluegrass. downy brome, and quackgrass, among others.

curly dock (Rumex crispus; perennial)

poison hemlock (Conium maculatum; biennial)

annual bluegrass (Poa annua; annual or short-lived perennial)

Additional information about these and other early season weeds can be found at these links:

• Early Spring Weeds of No-Till Crop Production Guide
• Rosette-Forming Weeds of Early Spring