It’s that time of year when weeds are beginning to show their ugly heads above the soybean canopy in many fields. During your scouting, if you find Palmer Amaranth or Waterhemp you should do whatever you can to prevent these devastating weeds from going to seed, including removing the entire plant from the field.
Each of the last 3 weeks I have included a post highlighting the different characteristics of Pigweed, Palmer Amaranth and Waterhemp. These posts also included a step by step video to help with the identification process for these weeds.
Depending upon the growth stage, identifying these weeds in the field can be challenging. If a seedhead is present, most weeds are easier to identify, including pigweed, palmer and waterhemp. If you have seen a mature palmer seadhaed you will never forget it! (see pictures above)
When trying to differentiate between these weeds I look for the following 3 plant characteristics:
1.Hair
Pigweed has hair the others do not. Rub the stem and leaves checking for a “rough” texture. Palmer and waterhemp will be smooth.
2. Leaves
Long Lanceolate Leaves
Waterhemp has long, slender leaves (lanceolate). While pigweed and palmer are more oval in shape. Pigweed is wider in the middle and palmer is wider near the base of the leaf (this is usually hard do differentiate in the field).
3. Petiole
The petiole is 
the part of the plant that connects the leaf to the stem. The petiole on palmer plant is as long or longer than the leaf. Pigweed and waterhemp have much shorter petioles (often less than 1/2 the length of the leaf).
These weeds are here, they best way to prevent the spread is by preventing them from developing a seedhead. One mature female plant can produce up to 1,000,000 seeds.
Weed Identification Videos
If you are still not sure about the identification, do not hesitate to call 740-397-0401) or send (barker.41@osu.edu) me a picture!!!