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Observers make science happen.

Pesky Plant Trackers are observing the life cycles of wild parsnip and knotweed. Here are some of their photos from across Minnesota.


What are you seeing? Share your image on this blog by emailing [email protected] with "Blog" in the subject line.


Charlie observes signs of frost kill

October 19, 2021

Knotweed with both brown and green leaves. Photo and observation by Charlie Rohwer. October 19, 2021 near Waseca, Minnesota.

Q: Do you see leaves?

A: Yes, one or more live, fully unfolded leaves are still visible on this patch of knotweed. Keep checking on your plant about once a week so you can observe the end of the 'Leaves' phenophase.

Q: When am I done observing?

A: Wrap up your season when you are ready. There is no universal end date. When the plant (or patch) you observe dies or goes dormant, that is a good time to pause until next year.


Crystal sees flowers drop, but no fruits forming

October 15, 2021

Q: One expects to see fruits form after flowers, correct?

A: Yes in general, but there are cases when this doesn't happen. When knotweed plants are under stress, they may drop flowers before fruits develop. Crystal is one of several observers who has waited for fruits but is not seeing them.

Q: Should you worry that fruits developed and fell off before you saw them?

A: No, not if you observe carefully every week and know how to identify fruits (click here for photo of unripe fruit). It takes 2-3 weeks for fruits to form. Therefore, your weekly routine will give you opportunity to see fruits if they are in fact present.

Japanese knotweed flowers
Photo taken near Grand Rapids, Minnesota by Crystal. October 15, 2021
Bare structure without flowers or fruits
Photo taken near Grand Rapids, Minnesota by Crystal. October 15, 2021


Bill seeds wild parsnip seedlings

October 14, 2021

Photo and observation by volunteer Bill on October 14, 2021. Near Becker, Minnesota. The first true leaves are visible on this young plant, which sprouted from seed in late summer or fall.


Knotweed phenophases, the "September edition"

October 12, 2021


Susan sees ripe and unripe fruits

October 11, 2021

Photo and observation by volunteer Susan, near Champlin, Minnesota, on October 11, 2021. Fruits have characteristic tear-dropped shape with 3 wings. Fruits are still white or pale green, meaning they are unripe.
knotweed fruits - ripe
Photos and observation by volunteer Susan, near Champlin, Minnesota on October 11, 2021. Ripe fruits have dry, papery texture and rusty-tan color.


Barb notices bare flower structures, only a few fruits

October 9, 2021

It is not unusual for knotweed flowers to fall before developing into fruits, or for unripe fruits to fall before ripening. Some observers may ask, won't that mean I never get to observe the last two phenophases, 'Ripe fruits' and 'Recent fruit drop'? Yes, possibly, but that's okay. Your records of what you see with your own eyes in the real world are much more valuable than generalized ideas of what's expected. When you report based on evidence you see, you're doing valuable science. Thanks, Barbara, for these photos!

knotweed fruit
Observed near Duluth, Minnesota on October 9, 2021. Most of the structure is bare of flowers or fruits. A few fruits remain attached, see detail below.
knotweed fruit - detail
Fruit are tear-drop shaped, compared to flowers which are trumpet-shaped. Fruits have three wings, in contrast to flowers which have 5 petals. These fruits are unripe.


Laurie sees fruits & dead flowers on knotweed

September 28, 2021

Observation and photo by volunteer Laurie. September 28, 2021 near St. Joseph, Minnesota.

Based on what is seen in this photo (click to enlarge), an observer could report on phenophases as follows:

  • Leaves? Yes
  • Flowers or flower buds? No (The rusty-colored structures are dead flowers. They are not fresh.)
  • Open flowers? No
  • Fruits? Yes (The pale green tear-dropped shapes are unripe fruits.)
  • Ripe fruits? No


Margaret decides their knotweed is Bohemian, not Japanese

September 26, 2021

Kudos to observer Margaret, who gathered different kinds of information and noticed that their knotweed is Bohemian, not Japanese. Some of the clues they used were:

  • Primary evidence: Conspicuous stamens visible in open flowers (see image below)
  • Supporting evidence: Leaf shape is floppy without flat base
  • Supporting evidence: The overall stand is tall, over 10 feet
Bohemian knotweed flowers
Photo and observation by Margaret, September 26, 2021. Bohemian knotweed near Duluth, Minnesota.

So what should Margaret do, now that the plant is identified?

  • If you have been collecting data on paper datasheets, you are now ready to enter your observations online. The steps are:
    • If you have not already done so, use the Nature's Notebook website to add your site to your account. (Watch a how-to video.)
    • Then add your plant to that site, with the correct species identification. (Watch a how-to video.)
    • Next, transcribe records from your paper datasheets to the website. (Watch a how-to video.) or the mobile app. If you do this on the mobile app rather than the website, be careful to select the correct data for every observation. You cannot change the date of an observation after submitting it.
  • If you have been collecting data in Nature's Notebook (app or website), but the species was misidentified, here are steps to take:
    • This kind of change must be handled by Nature's Notebook staff.
    • Take these steps to alert Nature's Notebook staff:
      • Go to your Observation Deck and scroll down.
      • Select the plant in question and click "Add or Edit Plants".
      • On the "Add or Edit Plants" page, make sure you are editing the correct plant (based on the site and nickname)
      • Click the checkbox next to "Delete?". A popup window will appear, asking why you want to delete the plant.
      • Select "Misidentified Species".
      • You will be prompted to contact Nature's Notebook for more information. In your message, explain to Nature's Notebook staff that you are seeing evidence to change the species identification from Japanese to Bohemian.


Susan sees flowers and fruits, both attached and fallen

September 19, 2021

Bare flower structures on knotweed
Photo and observation by volunteer Susan. September 19, 2021 near Champlin, Minnesota.

Sometimes knotweed flowers and fruits fall off the plant before developing. When collecting data, ignore parts that are fallen and only assess structures that are still attached to the plant.

 

Some flowers and fruits left on knotweed
Photo and observation by volunteer Susan. September 19, 2021 near Champlin, Minnesota.


Bobbie sees flowers, no fruits yet

September 21, 2021

Photo and observation by Bobbie, volunteer observer near Grand Rapids, Minnesota. Notice the closed buds which are smaller than open flowers.


Bill sees fruits, open flowers, and dead flowers on knotweed plants

September 20, 2021

Knotweed fruits and flowers
Fruits (unripe) can be seen among flowers on this Japanese knotweed plant. Photo and observation by volunteer Bill. September 20, 2021 near Becker, Minnesota.

Meanwhile, some flowers have died on this Bohemian knotweed plant (pictured below).

Fresh and dead flowers on knotweed
Brown, shriveled flowers are seen here amidst fresh, open flowers. Knotweed photo and observation by volunteer Bill. September 20, 2021 near Becker, Minnesota.


Sue starts observing Bohemian knotweed

September 18, 2021

Photo and observation by Sue, near Golden Valley, Minnesota, September 18, 2021

Do you see open flowers? Yes. Notice that the stalk is mostly bare, and several flowers have fallen off. This is common. When collecting data for Nature's Notebook, only assess parts of the plant that are still attached.

Is it too late to start observing knotweed in September? No. Observers may start whenever they are ready. For more about when to observe, see:

Do you see conspicuous stamen? Yes. Stamen are the long structures that extend beyond the petals. They are made up of filaments with anthers at the tip. When a knotweed has conspicuous stamen, it is not Japanese knotweed. It is probably Bohemian.


Lori sees flower buds (no fruit yet)

September 15, 2021

Photo and observation by Lori on 15 September, 2021 near Grand Rapids, Minnesota. These heart-shaped structures are closed buds, not fruits. An important clue is that closed buds are smaller than open flowers.


Knotweed along Elizabeth's path

September 14, 2021

Knotweed flowering, along a river gorge path
Photo and observation by Elizabeth Heeren, near St. Paul, Minnesota, September 14, 2021.


Susan sees a dark paper wasp on Japanese knotweed

September 13, 20221

Dark paper wasp on Japanese knotweed
Photo and observation by Susan. September 13, 2021 near Champlin, Minnesota


Bill sees knotweed fruit

September 13, 2021

Photo and observation by Bill, near Becker Minnesota, on September 13, 2021. Fruits are slightly larger than flowers.


Charlie sees knotweed fruit

September 10, 2021

Near Waseca, Minnesota, the first few fruits are appearing on knotweed plants.

Fruit appear on knotweed. Notice that fruit are slightly larger than flowers. At the end of the fruit, away from where it attaches to the plant, a brown style can be seen.

 


Bob sees high percentage of 'Open flowers' 

September 8, 2021

Do you see 'Open flowers'? Yes.

What percentage of all fresh flowers are open? This can be difficult to answer from a photograph, but the answer "75 to 94%" is reasonable.

Bohemian knotweed, open flowers
Photo and observation courtesy Bob Held, volunteer. Bohemian knotweed in Golden Valley, Minnesota. September 8, 2021.
Bohemian knotweed, open flowers
Photo and observation courtesy Bob Held, volunteer. Bohemian knotweed in Golden Valley, Minnesota. September 8, 2021.


Abbie sees fruits on var. compacta knotweed

September 7, 2021

This plant is exhibiting advanced phenology that we expect with the compacta variety. For contrast, non-compacta plants are not yet showing fruit.

Make sure your Nature's Notebook records include information about what kind of plant you observe. This is critical for scientists to appropriately analyze your data and make useful inferences. Click here for instructions how to do this.

knotweed (var. compacta) fruit
Examples of what are clearly fruit (two) can be seen directly above my thumb in this image. Observed in Minneapolis on Tuesday, September 7, 2021.


Bobbie observes knotweed flower buds

August 31, 2021

knotweed flower buds, observed by Bobbie S
Knotweed flower buds observed by Bobbie S near Grand Rapids, Minnesota on August 31, 2021.

 


Bob observes open flowers on hybrid knotweed

August 23, 2021

Open flowers, hybrid knotweed
Open flowers on hybrid (i.e., Bohemian) knotweed. Photo and observation by Bob Held on August 23, 2021. Near Golden Valley, Minnesota.


Elizabeth observes open flower on hybrid knotweed

August 17, 2021

Bohemian knotweed with flower buds and one open flower
Bohemian (hybrid) knotweed with flower buds and one open flower. Photo and observation by Elizabeth Heeren, August 17, 2021 near St Paul, Minnesota.


Barb observes knotweed flower buds

August 12, 2021

Knotweed flower buds
Knotweed flower buds. Photo and observation by Barb near Duluth on August 12, 2021.

Karen Kay observes knotweed flower buds

August 12, 2021

knotweed flower buds
Knotweed flower buds. Observation and photo by Karen Kay, near Champlin, Minnesota on August 12, 2021.

Jenean observes ripe fruit on wild parsnip

August 10, 2021

Ripe fruits on wild parsnip plants
Ripe fruit on wild parsnip plants. Photo taken early August, 2021 near Shafer, Minnesota by observer Jenean G.

Diane observes knotweed leaves damaged by beetles

August 6, 2021

Knotweed leaf with beetle damage
August 6, 2021 near Medicine Lake, Minnesota. Observation and photo by Diane Grey.

If you observe insect infestations or damage, describe what you see using the comment section of your Nature's Notebook observation.


Elizabeth observes knotweed with flower buds

July 30, 2021

First sign of flower buds, Bohemian knotweed
Early sign of flower buds on Bohemian knotweed. July 30, 2021 near St. Paul, Minnesota. Photo by Elizabeth Heeren.

Laura observes wild parsnip fruits ripening

July 6, 2021

Wild parsnip fruits starting to ripen
Wild parsnip fruits in the process of ripening. July 6, 2021 near Collegeville, Minnesota. Photo by Laura Kundrat

Sue observes open flowers on wild parsnip

June 15, 2021

Wild parsnip with open flowers
Wild parsnip with open flowers. June 15, 2021 in the Twin Cities area. Photo by volunteer observer Sue Fehr.

Elizabeth observes flower buds on var. compacta knotweed

June 12, 2021

Flower buds on dwarf Japanese knotweed (var. compacta)
Flower buds on dwarf Japanese knotweed (var. compacta). Seen in St. Paul on June 12, 2021. Photo by Elizabeth Heeren.

Steve observes webworm on wild parsnip flowers

June 11, 2021

Wild parsnip webworm on umbel
Wild parsnip umbel with webworm larva and web. June 11, 2021, seen in Twin Cities Metro area. Photo by volunteer observer Steve Poole.

If you observe insect infestations or damage, describe what you see using the comment section of your Nature's Notebook observation.


Sue observes wild parsnip flower buds (closed)

June 1, 2021

Wild parsnip - closed flower buds
Photo by volunteer Sue Fehr. Closed flower buds on wild parsnip. June 1, 2021 near Golden Valley, Minnesota.

Bill observes flower buds on wild parsnip

May 31, 2021

Wild parsnip photo by Bill Bronder
Wild parsnip in the 'Flowers or flower buds' phenophase. Flowers are not yet open. Photo by volunteer observer Bill Bronder, May 31, 2021. Near Becker, Minnesota.

Elizabeth observes vegetative growth of knotweed

May 29, 2021

Vegetative growth (not flowers) on Japanese knotweed
Vegetative growth (not flowers) on Japanese knotweed. Observed in St. Paul, May 29, 2021. Photo by Elizabeth Heeren.

Elizabeth observes 'Leaves' phenophase in knotweed

April 8, 2021

Japanese knotweed on April 8, 2021. Photo by Elizabeth Heeren.
Japanese knotweed "leaves" phenophase (unfolded leaf) on April 8, 2021. Photo by Elizabeth Heeren.

Byju observes 'Leaves' phenophase in wild parsnip

April 7, 2021

Wild parsnip, April 7, 2021, photo by Byju Govindan
Wild parsnip "leaves" phenophase (with unfolded leaves) on April 7, 2021 in St. Paul, MN. Photo by Byju Govindan

Elizabeth observes 'Initial growth' phenophase in knotweed

April 4, 2021

Japanese knotweed initial growth, April 4, 2021. Photo by Elizabeth Heeren.
Japanese knotweed shoot (initial growth) on April 4, 2021. Photo by Elizabeth Heeren.

Abbie checks for knotweed shoots

March 30, 2021

Checking for initial growth of knotweed
March 30, 2021 in Minneapolis, Minnesota. Photo by Ilene Krug Mojsilov

If possible, gently lift and then replace debris that could obstruct your view of shoots or early leaves. Materials such as dead leaves and other debris can play an important role for newly emerging plants by regulating their microclimate. Every site is slightly different so find a balance between detecting early signs of growth and leaving site conditions unchanged.


Byju observes 'Initial growth' phenophase of wild parsnip

March 26, 2021

Wild parsnip initial growth. Photo by Byju Govindan
Wild parsnip initial growth. March 26, 2021 in St. Paul, Minnesota. Photo by Byju Govindan.