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Green to Seed: Identifying time between buffelgrass green-up and seed set

Project Goals

Photo Credit: Joseph M. DiTomaasoBuffelgrass (Pennisetum ciliare, Cenchrus ciliaris) is a perennial grass invasive to the Sonoran Desert that threatens desert ecosystems by out-competing native species and altering fire regimes. An important tool for managing buffelgrass is applying herbicide at just the right time to kill the plant - after it is at least 50% green, but before the plant spreads its seeds. The length of time between 50% greenness and seed set is still unknown. Better knowledge of this window would enable managers to optimize when and where to apply herbicide so it is most effective. 

We need your help to identify this critical window! We seek volunteers to sign up as observers with Nature's Notebook and track the green up and seed timing of buffelgrass across southern Arizona. The data you collect as part of this project will be provided to local land managers to help them achieve the best results with the lowest amount of herbicide.  

How to participate...

1. Create a Nature's Notebook account - We suggest that you take the Observer Certification Course at

2. Find a site to monitor buffelgrass - Choose a convenient location that you will visit through Spring of 2023. Observations made at least once a week are ideal, but any amount of observations you can provide will be helpful. You can track a single plant or register a patch of plants and indicate the approximate size.

3. Take observations - We welcome you to answer all the questions on the buffelgrass datasheet. We are especially interested in the following questions:

  • How green is the buffelgrass? Answer the question "Do you see (green) leaves?" and if yes, the intensity question "What percentage of the plant is green?" using the bins provided on the buffelgrass datasheet. Optionally, you can include a more specific number in the comments section of your datasheet. 
  • How many flower heads do you see? Answer the question "Do you see flower heads?" and if yes, the intensity question "How many fresh flower heads are present?" using the bins provided on the buffelgrass datasheet. Optionally, you can include a more specific number in the comments section of your datasheet. 
  • Are there ripe seeds? Answer the question "Do you see ripe fruits?" You do not need to answer the intensity question, as it is difficult to count the number of seeds on the plant. 

4. Report your observations - As you collect data during the season, either use the Nature's Notebook mobile app or log in to your Nature's Notebook Observation Deck and enter the observation data you recorded on paper datasheets. 

Example of a datasheet with the three pieces of information we are most interested in: 

Buffelgrass completed datasheet

Questions about this research project? Contact Cynthia Wallace at

Questions about how to use Nature's Notebook? Contact Erin Posthumus at

Preliminary Data

2022 Summer Seasonal Story on buffelgrass green up to seed set timing