Yellow Hawkweed versus Dandelion

2017 July 5

Our lawn is heavily populated[1] by Yellow Hawkweed, Hieracium caespitosum, which has bright yellow flowers that bloom in June and July (these photos are from July 2, 2016).

The blossoms open up in the morning, making the lawn pretty much yellow,


but they close up again in the afternoon, making them look like just some sort of medium-height scrub.


The blossoms open and close several times before they finally set seed.



They are very attractive to bees, and the synchronized opening in the morning would tend to saturate a given area with hawkweed blossoms. This makes it more likely that bees will go from hawkweed to hawkweed and pollinate them properly, rather than taking excursions to other species of flowers and accomplishing nothing in the way of pollination.

Yellow hawkweed blossoms are pretty much the same color as dandelion blossoms (Taraxacum officinale), and they are commonly mistaken for dandelions. We also have dandelions in the yard, so here is a quick comparison:

Dandelion blossoms mostly bloom about a month earlier, are bigger, and have more of the pollen-bearing threadlike anthers


The dandelion plant also has broader, more obvious leaves


But, the most obvious difference is in the flower stems. Dandelion blossoms have hollow, soft stems that ooze huge quantities of white latex when broken off,


while the Yellow Hawkweed flower stalks are smaller in diameter, more fibrous, harder to break off, leak less latex, and most importantly are solid, not hollow.


Anyway, both Yellow Hawkweed and Common Dandelion are introduced invasive weeds, which because of their latex content are generally not very palatable to grazing animals (dandelions are edible when young before they build up their latex supply, but get pretty nasty when they are older. Hawkweeds are mildly nasty pretty much their whole lives.)

[1] It is quite possible that the majority of our lawn is various broadleaved plants, not grasses. It is more of a meadow that we whack the tops off of periodically than it is a traditional grass lawn.

6 Responses
  1. July 9, 2017

    Do you mow or are all the plants hugging the ground so mowing is not necessary?

  2. July 10, 2017

    We mow, but in June and July the lawn grows so very fast that it often gets away from us (and, when these flowers rocket up and bloom, we sometimes leave unmowed patches because we think they are pretty). Things taper off a lot in August and September, and mowing is pretty much unnecessary from October through until about the middle of May.

  3. July 26, 2017

    This was an interesting read. I didn’t know that difference between the two species.

  4. April Black permalink
    September 19, 2018

    Thank you. I’m going to have to compare our plants some more tomorrow. Our plants look JUST like dandelions but they’re at least 7 feet tall in spots. I’ve never seen dandelions grow that tall lol. They’ve lost their flowers, for the most part and have been shedding seeds all over the place. It looks a little like snow on parts of our driveway :O

  5. August 17, 2019

    Hi! I really enjoyed reading your post on the botanical differences, these 2 yellow asteraceaes are so similar.
    My name is Shana and I am creating an eat your weeds class and am seeking a pic of Dandelion’s hollow stem. It’s the one pic from my shotlist that I can’t seem to find and all the dandelions around me are done for the year.
    I mostly do my own photography for my classes as much as possible but have just started compiling pics of the proper quality and I am missing this very important one to the identification of Dandelion.
    I would appreciate using your pic, if your open to it. It’s the perfect shot showing both the hollow stem and milky latex.
    I’m happy to give you credit, or even pay for it.
    Thank you for considering!

  6. Kayla Henderson permalink
    August 23, 2019

    Hi there I have a question about the yellow hawkweed flower. LIl Dude my bearded dragon loves dandelions and I was wondering if yellow hawkweed is the same as a dandelion. Is it toxic in anyway. If anyone has any information I would appreciate it. Thanks

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