How to get rid of asiatic dayflower?

Garden Q&A: Is there any way to kill dayflower weeds?

I have been battling some weeds in my flower garden that won’t quit. They have short, pointed leaves and small blue flowers. I kind of thought they were pretty when I first saw them, but they root where they touch and they take over everything. I’ve been pulling them for months but they spring right back up. How can I get rid of them?

I think the weed you are fighting is a called a dayflower, Latin name Commelina comunis. While pulling them up can feel quite rewarding at the end of the day (you are left with bushels of wilting weeds to show for your labors) each tiny fragment of root left behind soon sprouts a new plant and the whole game begins again. It’s kind of maddening, isn’t it?

This is one of those weeds that calls for a careful herbicide choice. It’s one of the rare times I would use a non-selective herbicide. I don’t recommend it for all weeds. In fact, before I used it recently, I walked through the area and pulled the ones I knew responded best to being pulled. I had a “lovely” assortment: Asiatic hawksbeard, some chamberbitter and a new one this year, cupid’s shaving brush. Because a flower bed is disturbed ground, it a fertile spot for weed seeds to land and take root.

All of these weeds I mentioned are a waste of herbicide and should be pulled; 5 to 10 minutes a couple of days a week and you can keep them under control. The cupid’s shaving brush and chamberbitter would have merrily spread their seeds long before the herbicide killed them so I would have lost the war had I just gone ahead and left it to spraying. Chamberbitter looks a little like a Christmas tree with seeds on the undersides of the branches and I suspect each of those seeds would have grown a new weed, based on my dismal experiences.

I am careful to mix my Glyphosate according to directions and you should be too. I use disposable gloves and a household spray bottle I have clearly labeled. Note that I do not use my garden gloves. I do not wear sneakers. I wear my garden shoes. which are rubberized, and I rinse them afterward. Am I being cautious? Yes. I try not to track dirt and mud in my house; herbicide doesn’t seem like a good idea either.

Because a non-selective herbicide will kill whatever it lands on, you have to spray carefully. With the dayflower, remember they are all interconnected so you don’t actually have to spray every single piece. This is useful if you are working in a bed of chosen plants. I hand weed around all the plants that are valuable plants. I also clean out around terra cotta pots by hand because I’m not sure how much of the herbicide might be absorbed by the clay pot. If I accidentally spray a plant leaf I love, I quickly pull that leaf off the plant.

Glyphosate works by entering the plant through that leaf and moving throughout the plant and eventually killing it. Removing that leaf saves the rest of the plant.

It takes one to two weeks for the glyphosate to move through the plant and kill it. Some spots will have been missed and will pop right out. It’s not a weed you can trust or slay easily.

After doing all this, I learned that the dayflower has become resistant to Glyphosate and may just falter a little and then rebound and go back to taking over my garden. So, I attack again. It is not resistant to Imaquizine products such as Image. You must use the preparation that is labeled for nutsedges (there are several other preparations on the market and the others will not work). Gardening is not for wimps!

For several years I have been buying amaryllis bulbs. I just pick the ones I think are really pretty. I’ve allowed them to go to seed, and I’ve planted the seeds and now the seedlings’ leaves are flattening out and looking more like the parent bulb leaves. Is there anything more I need to do?

Sounds like you are doing an awesome job because you have a huge number of amaryllis seedlings coming along. You have all the right attributes for this job: you are willing to be patient and you love the parent plants and are willing to take whatever comes. With the mixing of genetics in the seeds, you could have anything, including something remarkable in your little seedlings. It takes 2 to 4 years for the seedlings to bloom. All they should need is the same care you give their parent plants and they will continue to grow and thrive.

Becky Wern is a master gardener with the Duval County Extension Service and the University of Florida/IFAS. If you have gardening questions, you can speak to a master gardener from 9:30 a.m. to noon and 12:30 p.m. to 3:30 p.m. Monday through Friday at the Duval extension office at (904) 255-7450.

In The Grow Question and Answer – Pretty ground cover? Probably a weed

Q: I’m having an argument with my wife about a plant in our yard, and we hope you can help arbitrate. I’ve sent a photo of a plant that we found growing near some shrubs. Neither of us remember planting it. My wife thinks it’s pretty ground cover and that we should let it stay. I think it’s a weed and that we should get it out of there before it takes over the whole bed. My wife said, “ask Rosie!”— W & M, Lebanon, Indiana

A: You could both be right, but if I have to choose, I’d say you win the argument! Your photo appears to be Commelina communis, more commonly known as Asiatic dayflower. I’ve included a photo that shows both flowers and leaves. It does have pretty blue flowers, but this non-native plant is generally considered a weed. Because the plant tends to sprawl along the ground, the stems root when they stay in contact with moist soil. This species can form a dense colony that outcompetes other plants. Dig the plant out, removing as much of the root system as possible.

There is a native, closely related species known as slender dayflower, Commelina erecta, that has more narrow-shaped leaves, is more upright, does not form dense colonies, and tends to be found in drier soils.

For more information about each of these species:

Asiatic dayflower – https://www.illinoiswildflowers.info/weeds/plants/asia_dayflower.htm

Slender dayflower – http://www.illinoiswildflowers.info/prairie/plantx/sl_dayflower.htm

Q: What causes Christmas cactus leaves to turn red? Will this cause the plant to die? – D.C., South Bend, Indiana

A: Leaves of holiday cactus often turn red or reddish purple if exposed to excessive light. Too much direct sunlight can actually burn the leaves or may cause them to become limp. This should not cause the plant to die, but burned leaves may fall off. An otherwise healthy plant will be able to grow new leaf segments. Try moving the plants a bit further away from direct light.

Eradicating Asiatic Dayflower??

I know beauty is in the eye of the beholder, and I do love the pretty little pops of blue all summer, but I’ve had enough! I have dug up- by hand- 5 garden beds within the past year… mostly because I have been discouraged by the sheer amount of Asiatic Dayflowers in the garden bed that came with the house. I have visions for this bed, and while it could be easy enough to eradicate the undesirables with chemicals, I’m trying my best to steer clear of those types of products. Have a look:

See that area in between the porch and the sidewalk? FILLED with those little boogers!
A closer look at my arch nemesis.
Please, please, PLEASE ignore all the clutter.
All the tiny little seedlings are popping up left and right at this point, and I do NOT want them going to seed this year. Should I keep pulling away? Should I boil a whole bunch of water and toss is out there? Should I solarize them or smother them out? I’m used to trying to make things thrive, not killing them! Any input is greatly appreciated!

Family:

Sunflower Family (Asteraceae)

Other Names:

Origin and Distribution:

Chicory originated in the Mediterranean and became distributed throughout much of the world where it was grown for centuries as a salad green. Its cultivation in North America began in the 1700’s and ended in about 1950 when it became more economical to import chicory. During that time, chicory escaped cultivation and naturalized populations spread throughout southern Canada and the U.S., where it is most commonly found it in the north and west. In Ohio, it occurs throughout the state. Chicory grows abundantly besides roads and highways. It can also be found in lawns, pastures, fields, and waste places. The plant favors lime-rich soils but tolerates a variety of soil types.

Plant Description:

Chicory is a perennial that initially grows as a rosette of irregularly-toothed basal leaves. Then, later in the season, leafless stems emerge with sky-blue daisy-like flowers scattered along their length. Flowers open each morning and close as sunlight increases in intensity around noon. Only a few flower heads open at a time and each head opens for a single day. Chicory reproduces by seeds.

  • Root System:

    Plants produce a thick, deep, sturdy taproot containing a very bitter and milky juice.

  • Seedlings and Shoots:

    Young leaves are oblong to egg-shaped, pale green, shiny, and contain a bitter and milky juice in the midvein.

  • Stems:

    The erect, round, hollow, nearly leafless stems produce stiff spreading branches that can grow 1 to 5 feet tall. Lower portions of stems are hairy. Upper portions are generally without leaves making stems appear straggly. Stems exude a milky sap if cut.

  • Leaves:

    Rosette leaves are 2 to 6 inches long, oblong or lance-shaped, and covered with rough hairs on both the upper and lower surfaces. Margins of basal leaves are either deeply dissected with pointed lobes or they may be shallowly toothed. Stem leaves are small, sparse, alternate (1 leaf per node), lance-shaped, and clasping. Stem leaves have smooth or slightly toothed edges.

  • Flowers:

    The showy flowers are clustered in heads that are 1 to 1 1/2 inches wide, short-stalked or stalkless, and borne in clusters of 1 to 4 on the upper branches. Each flower head consists of many individual, bright blue, petal-like flowers that are squared-ended and toothed.

  • Fruits and Seeds:

    The single-seeded fruits are about 1/8 inch long, dark brown, wedge-shaped, and 5-angled.

Similar Species:

Rosette leaves of chicory closely resemble those of dandelion (Taraxacum officinale); however, basal leaves of chicory are coarser and have more prominent hairs compared with dandelion leaves.

Biology:

Flowering occurs from June through September. Flowers generally bloom in the morning, track the sun, and close when sunlight is brightest at mid-day. The average plant produces about 3000 seeds. Chicory does not tolerate cultivation.

Toxicity:

None known. However, chicory sometimes causes contact dermatitis in humans.

Facts and Folklore:

  • ‘Intybus’ was derived from the Egyptian word for January, which was when chicory was harvested and eaten many thousands of years ago in Egypt.

  • Chicory is considered a salad green rather than a weed in Europe; fresh leaves are sold as radicchio in Italy and the French produce a green they call whitloof chicory, Belgian endive, or French endive by forcing chicory roots to sprout while deprived of light.

  • It is common to roast the roots and use them as a coffee substitute or additive. Roots can also be eaten raw or boiled, or they can be dried, ground, and used as seasoning.

  • Chicory is a productive and high quality forage crop that functions well in rotational grazing systems.

  • The flowers were once used to make a yellow dye while the leaves made a blue dye.

  • Folk remedies used chicory roots for jaundice, spleen problems, and constipation and a tea made from foliage supposedly promoted bile production and released gallstones.

  • In one legend telling of chicory’s origin, a beautiful maiden refused the advances of the Sun and was turned into a chicory flower that had to stare at the Sun each day and always faded in the presence of its might.

Asiatic Dayflower: An Increasing Weed Problem in Missouri Corn and Soybean Fields

Kevin Bradley
University of Missouri
(573) 882-4039

Published: May 10, 2012

If there’s one thing we have seen in our agricultural production fields over the past several decades, it’s been a change in our predominant weed species.

These weed “shifts” usually occur in response to some specific pressure that has been placed on them. Since 1996, this pressure has come in the form of the rapid adoption of Roundup Ready cropping systems and the continuous use of glyphosate. As a result, we are starting to see a shift in our fields to those weeds that glyphosate does not control. One of these weeds is Asiatic dayflower (Commelina communis).

In the past two weeks I have received numerous calls about the control of this species in no-till corn and soybean fields. We have given presentations and written several newsletter articles on this species in the past, so I will only briefly summarize here.

First, I believe there is an increasing awareness about this species among our clientele, but I also believe that we have more work to do and that there are many who are completely unaware as to the identity of this plant. In some surveying we have done over the past several years, we have encountered this species on a fairly regular basis throughout the state, especially in no-till soybean fields. It is a species that can form thick canopies and cause significant yield losses, not to mention the fact that it is difficult to control.

Asiatic dayflower seedlings more closely resemble a “wide-leaved” grass plant when they first emerge in the spring (Figures 1 and 2). Asiatic dayflower can have an erect growth habit but more commonly creeps along the ground and is capable of rooting at the nodes. The leaves occur alternately along the creeping stem and are ovate to lanceolate in outline, as much as 5 inches long and 2 inches wide. All leaves and stems are hairless, and each leaf has a membranous sheath which encircles the base of the leaf and stem (Figure 3). The flowers of Asiatic dayflower consist of two, very distinctive large blue petals with one white petal below (Figure 4). Asiatic dayflower generally blooms from mid- to late-summer in Missouri, with each flower blooming for a single day (thus the name). Several authors have found that the seed of Asiatic dayflower are capable of germinating throughout the growing season and that the seed can also remain viable in the soil for more than 4 ½ years.

Figure 1. Newly-emerged Asiatic dayflower seedlings are often confused as a grass plant with wide leaves. However these plants do not have a ligule or any of the typical characteristics of grasses.

Figure 2. Young Asiatic dayflower plants newly emerged in the spring. It doesn’t take long for the plants to “tiller” and produce multiple shoots from a single rootstock.

Figure 3. Note the membranous sheath which encircles the base of the leaf and stem. Because of this, many have miss-identified Asiatic dayflower as one of the smartweed species.

Figure 4. Notice the two blue petals above and one white petal below that are characteristic of the flowers of Asiatic dayflower.

Few herbicides provide acceptable control of Asiatic dayflower in soybeans. Firstrate, Sencor, and the Authority products are some of the only herbicides that will provide acceptable Asiatic dayflower control when applied as a pre-emergence treatment. Similarly, Firstrate is one of the only conventional herbicides that will provide acceptable control of this species when applied as a post-emergence treatment in soybeans, but applications must be made before this species reaches six inches in height. Even high rates of glyphosate in Roundup Ready soybeans will usually only provide a moderate degree of suppression (<50% control).

In corn, there is much less information available about the control of this weed in the weed science literature. I usually get far fewer questions on the control of this weed in corn, and I suspect that the use of atrazine in our corn production systems is the reason. S-metolachlor, or products that contain this herbicide (Dual, Bicep II Magnum, Lexar, Lumax, etc.) provide some degree of residual control of this species. Based on some research on the control of a similar dayflower species that occurs in the south, it appears that Aim has good post-emergence activity on dayflowers, and that a post-emergence program that includes Aim + S-metolachlor + glyphosate provides good control of populations that weren’t initially controlled with a pre-emergence herbicide program. As mentioned previously, I’m sure there are other post-emergence programs that provide equivalent or higher levels of Asiatic dayflower as well; there just isn’t much information on this species in the literature.

Asiatic Dayflower (Commelina communis)
Asiatic dayflower is an annual weed in the monocot family that is becoming more of a problem particularly in no-till soybean fields throughout the Midwest. Asiatic dayflower has blue flowers and roots at the ground where it comes in contact with the soil. It forms dense colonies that can cause severe yield losses in both corn and soybean (Figures 3-5).
Few herbicides provide acceptable control of Asiatic dayflower in soybeans. Recently, weed scientists at Iowa State have conducted a number of trials to identify treatments for the management of this species. This research has revealed that in soybeans, Spartan, Firstrate, and Sencor are some of the only active ingredients that will provide acceptable Asiatic dayflower control when applied preemergence. Similarly, Firstrate is one of the only conventional herbicides that will provide acceptable control of this species when applied as a postemergence treatment in soybeans, but applications must be made before this species reaches six inches in height. Many other preemergence and postemergence herbicide treatments that have
been evaluated, including Command, Dual, Define, Valor, Resource, Cobra, and Aim, provide little to no control of Asiatic dayflower. Glyphosate at standard rates in Roundup Ready soybeans will usually only provide some degree of suppression, and the calls I’ve received lately regarding this weed suggests to me that our common glyphosate burndown programs are providing little to no control of this species. Other research has shown that increasing the rates and making at least two applications of glyphosate can provide higher levels of Asiatic dayflower suppression and also that three applications of glyphosate at 0.75 lb a.e. per acre can provide about 80% control. Based on all of the available research, it seems clear that preemergence programs that include Sencor or Firstrate are the most effective and economic way to manage this species in soybean.

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