Isolated Female Waterhemp Plant Produced Seed: Implications that pollen is in the air

Updated September 09, 2024

Eric Jones

Assistant Professor and SDSU Extension Weed Management Specialist

Additional Authors: Philip Rozeboom

Written collaboratively by Eric Jones, Philip Rozeboom, Jill Alms, and David Vos.

There has been a lone, isolated female waterhemp plant growing at the building where the SDSU Extension Weed Science Program operates during the growing season (Figure 1). The plant is finally mature and has produced seed (Figure 2). The remarkable note about this isolated female waterhemp producing seed is that the nearest waterhemp plants are about 100 yards away (Figure 3).

A tall, green waterhemp plant next to a wooden bench, sidewalk, and red-brick building.
Figure 1. A lone, isolated female waterhemp. The plant has been growing in this garden area all summer and has finally produced flowers containing seed.
Small, green and yellow florets being held by a hand.
Figure 2. Florets containing viable seed from the isolated female waterhemp plant. This female waterhemp plant has produced at least 100,000 viable seeds.
A picture of some blue and white sheds amongst a brown, gravel driveway and green lawn. A yellow circle in the background denotes the location of waterhemp plants.
Figure 3. The closest waterhemp plants (circled) to this isolated female plant are at least 100 yards away. The fact the isolated female plant produced seeds from pollen 100 yards highlights the fact that waterhemp should be managed within the field and in areas adjacent to the field.

Previous research has shown that male plants can be 875 yards away and still have successful pollination of female plants (Liu et al. 2012). Previous research has also provided evidence that female waterhemp plants growing without competition can produce several hundred thousand seeds, where most will germinate and need to be managed in future growing seasons (Jones et al. 2019). Another noteworthy remark is that seeds become viable within 7 to 12 days of pollination (Bell and Tranel 2010).

While this result may not shock some, the fact that pollen can move relatively far distances to pollinate isolated female plants further highlights the need to effectively manage weeds in your field and adjacent areas. Herbicides will not control a plant this large, but simply cutting the single plant off at the soil surface and destroying the plant and seeds will significantly reduce the amount of waterhemp plants that germinate next year in this area. Use this as an example why it is always worth the effort to pull and remove a single or a few plants near your fields.

References

  • Bell MS, Tranel PJ (2010) Time requirement from pollination to seed maturity in waterhemp (Amaranthus tuberculatus). Weed Sci 58:167–173
  • Jones EAL, Owen MDK, Leon RG (2019) Influence of multiple herbicide resistance on growth in Amaranthus tuberculatus. Weed Res 59:235–244
  • Liu J, Davis AS, Tranel PJ (2012) Pollen biology and dispersal dynamics in waterhemp (Amaranthus tuberculatus). Weed Sci 60:416–422

Related Topics

Corn Weeds, Soybean Weeds, Wheat Weeds

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