2018 update: Common garden experiment–1996 cohort

In 2018 only 19% of the plants flowered, despite it being a burn year. Is the 1996 finally showing its age?

In 2018, 51 plants flowered of the surviving 269 plants in the 1996 cohort. That means that 41% of the original plants are surviving and 19% of the living individuals flowered. That’s up huge since last year, where only 2% flowered, and the year before where five percent of living individuals flowered. In contrast, however, 45% of living plants flowered in 2015, and  37%, 34%, and 40% flowered in 2014, 2013, and 2012 respectively. We found that of the original 646 individuals, 269 were alive in 2018, only 15 fewer than last year. We are not sure why so many more plants flowered this year. It’s probable that the fire in the plot in fall 2017 influenced flowering rates.

The 1996 cohort has the oldest Echinacea plants in experimental plot 1; they are 22 years old. They are part of a common garden experiment designed to study differences in fitness and life history characteristics among remnant populations. Every year, members of Team Echinacea assess survival and measure plant growth and fitness traits including plant status (i.e. if it is flowering or basal), plant height, leaf count, and number of flowering heads. We harvest all flowering heads in the fall, count all achenes, and estimate seed set for each head in the lab. As yet, these heads are still waiting to be cleaned April 2019.

Start year: 1996

Location: Experimental plot 1

Overlaps with: phenology in experimental plots, qGen3, pollen addition/exclusion

Physical specimens:

  • We harvested 59 heads. At present, they await processing in the lab to find their achene count and seed set.

Data collected:

  • We used Visors to collect plant growth and fitness traits—plant status, height, leaf count, number of flowering heads, presence of insects—these data have been added to the database
  • We used Visors to collect flowering phenology data—start and end date of flowering for all individual heads—which is ready to be added to the exPt1 phenology dataset
  • Eventually, we will have achene count and seed set data for all flowering plants (stay tuned)


  • See the exPt1 core dataset where yrPlanted == ‘1996’ for 1996 cohort fitness measurements
  • Amy Waananen’s paper, Mating opportunity increases with synchrony of flowering among years more than synchrony within years in a nonmasting perennial, published last year in The American Naturalist, was based on plants in this cohort.

You can find more information about the 1996 cohort and links to previous flog posts regarding this experiment at the background page for the experiment.


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