Recognition of Winter Annuals – Part 1

Winter annuals have been appearing in gardens, lawns and landscapes for the past several months. These plants can be recognized through their characteristic shapes, and peculiarities, with a special focus on leaves since many will not bloom until spring.  The human brain has an incredible capacity for visual pattern recognition.  With practice and repetition, most of us can identify the common winter annuals from their earliest stages.  This is very helpful to gardeners and conservation managers, who want to eliminate undesirable weeds before they mature and multiply.

Occasionally, mistaken identities result in humorous plantings in public or private gardens.  In the municipal garden shown below, a small specimen of Senna obtusifolia – Sicklepod – was raised unknowingly as an ornamental shrub.  Watered and carefully tended by the garden staff, it reached huge proportions before someone explained the mistake.  The staff now fights large crops of young sicklepods that come up every spring all over that garden.

Senna obtusifolia Sicklepod Shrub

Senna obtusifolia
Sicklepod
Shrub

Here is a brief display of a few interesting  visual patterns seen in five winter annuals, and  one summer annual.   All of the plants are very common in the North Carolina Piedmont.  See if you recognize some of them.  The names are listed at the end.

Plant #1

img_1165-young-sherardia

Plant #2 (Perhaps the most difficult of the group)

img_1168-toadflax

img_1170-nuttallanthus-canadensis

Plant #3 (Actually blooming in the 2nd photo)

img_1806a-scleranthus-annuus

img_1812-scleranthus-annuus

Plant #4

img_1797-erigeron-annuus

Plant #5

img_1808-erodium-cicutarium

img_1810-erodium-cicutarium

Plant #6 (The summer annual)

img_1802-lobelia-inflata

The identities of the plants are:

Plant #1 is Galium sherardia  –  Blue Field Madder

Plant #2 is Nuttallanthus canadensis  –  Blue Toadflax

Plant #3 is Scleranthus annuus – Knawel

Plant #4 is Erigeron annuus – Annual Fleabane

Plant #5 is Soliva sessilis – Burweed

Plant #6 is Lobelia inflata – Indian Tobacco

The Blue Toadflax plants seem more like young succulents and are often among the most difficult to identify.  More details about each plant will follow in the next article.

Herb Amyx

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4 Responses to Recognition of Winter Annuals – Part 1

  1. Bryan says:

    So true! The very, very young spouts of toadflax really do look just like a tiny creeping sedum, and nothing like mature toadflax. They even have little succulent leaves whorled in 3s when they are first sprouting (I admit I’ve been fooled by them before). Thank you for posting photos of these (often confusing) early growth stages.

    And I would not have guessed photo #5 was going to turn into Storksbill — I would have thought it was a Burrweed (Soliva), it looks so much like one.

  2. Great call! It is Lawn Burweed and not Storksbill. They look so much alike I grabbed and posted the wrong photos. Storksbill has a more complex compound leaf as it matures, but the quick way I use is to magnify the tips of the leaves. The Burweed has little spikes on the tips of the leaves and Storksbill does not. Thanks for the correction!

  3. Tamsin bomar says:

    Will your future posts address the ecological value of these winter annuals? If not, would you refer me to some sources for that information?

  4. Yes, each plant mentioned above will be discussed in the next article, including its value, or lack thereof, depending on the eye of the beholder. Also, Virginia Tech has an excellent website that briefly gives the background of common weeds and wildflowers. The link is
    http://oak.ppws.vt.edu/~flessner/weedguide/

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