The line separating what is a weed and what isn’t often comes down to where the “weed” is growing and who is managing the area it’s growing in. Blue Eyed Grass (Sisyrinchium rosulatum), one of the most complained about lawn weeds this winter/spring falls squarely in that category! Native plant enthusiasts and homeowners looking to add native wildflowers to their landscape value the plant for its low maintenance, star-shaped blue blossoms in spring. Professional and home turfgrass managers, however, loathe the plant as it masquerades as grass to the untrained eye, looks messy in the cool months, and can displace turf during spring green up. While Blue Eyed Grass can be a pretty landscape plant, our focus today is on learning why it is such an annoying weed in turfgrass areas and exploring control options if it becomes a problem!
Blue Eyed Grass (Sisyrinchium rosulatum) in a Centipedegrass lawn in late March. Photo courtesy of Daniel Leonard.
For starters, Blue Eyed Grass (BEG) is not even a grass, though it does look an awful lot like one! It is actually a member of the Iris family and is more closely related to spring beauties like Gladiolus, Iris, and Crocus than any turfgrasses. The flowers, appearing late March through April, are a dead giveaway that we aren’t dealing with a grass, as are the flat leaves arranged in bunched fan-shaped rosettes. BEG is considered a winter annual plant in Florida, meaning it sprouts from seed in the fall, grows through the winter, then flowers and sets seed in the spring. Because it grows while lawn grass is dormant, it is very noticeable during its entire lifespan. Though BEG can tolerate a range of soil types, it prefers to grow in moist areas, making it right at home in Panhandle lawns and landscapes in the winter as we experience regular to excessive rainfall throughout our cool season.
All the above characteristics make BEG an annoying weed in lawns. It hides in turfgrass very well until the turf goes dormant in the dead of winter, leading most homeowners to ignore it until it becomes a problem in the spring. At this point, BEG is nearing maturity and is more difficult to control without damaging the turfgrass. BEG also thrives in our climate and can outcompete poorly managed turfgrass, especially if the lawn exhibits the soggy, compacted conditions that heavy lawn foot traffic and winter/spring rainfall cause. So, what is a homeowner to do?
The first step in controlling BEG is maintaining a healthy turf. Ensure you’re treating your turf well during the growing season by fertilizing appropriately, mowing frequently at the correct height, and irrigating properly. Sending turf into the dormant season stressed by poor growing season management is an invitation to winter weeds. Other cultural practices that can help mitigate troublesome winter weeds like BEG are periodic mowing during the cool season to prevent weeds from going to seed and being diligent about not frequently driving on, parking cars on, or otherwise excessively compacting the soil, a common cause of unhealthy turfgrass.
Blue Eyed Grass clump brought into the Calhoun County Extension office for identification and control recommendations in February 2021. Photo courtesy of Daniel Leonard.
After implementing the above cultural practices in your lawn management regime, you may also need chemical herbicides to achieve a clean cool season lawn. There are two basic options for BEG control. First, a fall (mid-late October) application of a pre-emergent herbicide like dithiopyr, prodiamine, or pendimethalin can be very effective at preventing winter weeds from occurring at all. If you happen to miss this fall pre-emergent application, a timely post-emergent application of 2,4-D or other general broadleaf herbicides works nicely as well. (BEG and other cool season weeds are best controlled with post-emergent herbicides in December and January before they mature and begin to set seed. Plan applications accordingly!)
While Blue Eyed Grass can be an attractive addition to the landscape, it is never welcome in turfgrass! To prevent this and weeds from becoming a problem, use smart cultural practices to maintain a healthy turf and make timely herbicide applications when needed. For more information on controlling Blue Eyed Grass and other winter weeds, contact your local UF/IFAS Extension office!
As a boy in a small town in Georgia we had a St. Augustinegrass lawn. My dad started the lawn before I was born. That lawn was still doing fine when I left for college at age seventeen. I don’t remember weeds in the lawn during summer months. I do fondly remember winter “weeds” in that lawn.
To see clumps of winter annuals in our yard and in neighbors’ yards was a natural part of the transition from winter to spring. They added interest to what
Blue Easter egg hidden in chickweed. Photo credit: Larry Williams
would have been a plain palette of green. It was expected to see henbit with its square stiff stems holding up a display of small pinkish purple flowers in late winter and early spring. A clump of henbit was a great place to hide an Easter egg, especially a pink or purple one.
Wild geranium, another common winter annual, offered another good hiding place for Easter eggs with its pink to purple flowers. Large clumps of annual chickweed would nicely hide whole eggs. Green colored eggs would blend with chickweed’s green leaves.
Pink Easter egg hidden in crimson clover & hop clover mix. Photo credit: Larry Williams
Crimson clover with its reddish flowers, hop clover and black medic with their bright yellow flowers were good hiding places for Easter eggs. Plus clovers add nitrogen back to our soils.
I never remember my dad using any weed killer, he rarely watered. The lawn was healthy and thick enough to be a deterrent to summer weeds. But during fall and winter as the lawn would naturally thin and go dormant, winter annual weeds would run their course.
I’ve heard that the sense of smell provides our strongest memories. I remember the first mowing of the season with the clean smell of chlorophyll in the spring air. It was refreshing. Once mowed and as the heat took its toll, by late April or mid-May, these winter annual weeds were gone. What was left was a green lawn to help cool the landscape as the weather warmed. The lawn was mowed high as St. Augustine should be, played on and typically not worried with.
Most people have winter weeds in their lawns that let us know spring is near. Perhaps we worry too much with these seasonal, temporary plants that may have wrongly been labeled as weeds. Besides, how long have we been doing battle with these weeds and they are still here. Most lawns have countless numbers of winter annual seeds awaiting the cooler temperatures and shorter days of early winter to begin yet another generation. By May they are gone.
The weather is warmer and plans and planting for spring vegetable gardens are in full swing. Last week many vegetable gardening topics were addressed in our Gardening in the Panhandle LIVE program. Here are all the links for all the topics we discussed. A recording of last week’s webinar can be found at: https://youtu.be/oJRM3g4lM78
Home grown Squash. Gardening, vegetables. UF/IFAS Photo by Tom Wright.
Our moderators talked about some of their favorite tomato varieties. Josh Freeman is partial to Amelia, a good slicing tomato. Matt Lollar shared some of the best tomato varieties for sauce: Plum/Roma types like BHN 685, Daytona, Mariana, Picus, Supremo and Tachi. For cherry tomatoes, Sheila Dunning recommended Sweet 100 and Juliette.
Whatever variety you choose, Josh says to pick when it starts changing color at the blossom end and bring it indoors to ripen away from pests.
Garden Pest Management
Let’s start with an underground pest. For those of you gardening in the native soil, very tiny roundworms can be a problem. Nematode Management in the Vegetable Garden can get you started: https://edis.ifas.ufl.edu/pdffiles/NG/NG00500.pdf
There are beneficial creatures helping to control the pest insects. Learn to recognize and conserve them and make for a healthier environment. Natural Enemies and Biological Control: https://edis.ifas.ufl.edu/pdffiles/IN/IN12000.pdf
If the beneficials are not numerous enough to control your pests, maybe a natural approach to pest control can help. Natural Products for Managing Landscape and Garden Pests in Florida: https://edis.ifas.ufl.edu/in197
Companion planting is a strategy that has been around for ages and for good reason: https://www.almanac.com/companion-planting-chart-vegetables Some good flowering additions to the garden that Sheila talked about are bee balm, calendula, marigold, nasturtiums, chives, and parsley.
Gardeners worldwide and throughout time have bemoaned weeds. In Florida, we get to enjoy weeds all year long! Our February Gardening in the Panhandle (GIP) Live episode focused on weeds and weed control. Many homeowners are interested in ways to control weeds and UF/IFAS Extension and your local extension agents are here to help. The following is a summary of the topics we discussed and links for more research-based information on weeds.
What is a Weed?
Many folks come to the extension office holding a plant and ask, “Is this a weed”? Well, whether it is a weed or not is up to the individual, as the only definition for a weed is “a plant out of place”. Bermudagrass and Oxalis are good examples of plants that some try to grow while others try to kill. One person’s weed is another’s wildflower! However, to be clear, plants classified as invasive by UF/IFAS and governmental entities are officially weeds. There are resources to help identify several common plants that are generally considered weeds by most homeowners and landscapers.
There are some general gardening practices that can help prevent weeds so there is less of a need to control them. A lawn that is healthy is less likely to be invaded by weeds and the use of mulch can greatly reduce weed growth in planting beds. Other practices, like the placement of weed fabrics/cloths are less effective and/or less practical in many garden situations.
Once you know and/or decide that what you have is a weed and that it needs to be dealt with, then you have to consider your control options. Prevention, as mentioned above, is key but sometimes you may need to use other methods of control, such as physical, mechanical, and/or chemical means. With chemical weed control, it is important to always read and follow the product label.
General dates of common annual weed emergence. Credit: Dr. Ramon Leon, UF/IFAS.
Specific Weed Recommendations
When managing pests, proper identification is key to effective control. Because some weeds are annuals, and present either during the cool or warm season, and others are perennials, proper weed identification can provide a more detailed control strategy. Use the weed ID links above and the document links below for more precise, and effective, weed management.
If you need additional assistance with weed control, please contact your local county extension office. Please tune in for future GIP LIVE episodes for more research-based information on gardening topics.
We are back with new topics and guest speakers for 2021! All sessions are Thursdays at noon CDT or 1:00 p.m. EDT.
There are two ways to join the Gardening in the Panhandle LIVE! webinars:
1. Facebook Live – Follow us on Facebook and follow individual webinar Events.
2. Zoom Webinar – Pre-registration is required for Zoom. Users must have an authenticated account (free at Zoom Link). Be sure you have security settings up to date to prevent connection delays. Links to Zoom registration will be added to the topic one week before the webinar and a closed captioned recorded link to YouTube will be available approximately one week after the program. (Underlined words have active links!)
2020 has not been the most pleasant year in many ways. However, one positive experience I’ve had in my raised bed vegetable garden has been the use of a cover crop, Buckwheat (Fagopyrum esculentum)! Use of cover crops, a catch-all term for many species of plants used to “cover” field soil during fallow periods, became popular in agriculture over the last century as a method to protect and build soil in response to the massive wind erosion and cropland degradation event of the 1930s, the Dust Bowl. While wind erosion isn’t a big issue in raised bed gardens, cover crops, like Buckwheat, offer many other services to gardeners:
Buckwheat in flower behind summer squash. Photo courtesy of Daniel Leonard.
Covers, like Buckwheat, provide valuable weed control by shading out the competition. Even after termination (the cutting down or otherwise killing of the cover crop plants and letting them decompose back into the soil as a mulch), Buckwheat continues to keep weeds away, like pinestraw in your landscape.
Cover crops also build soil. This summer, I noticed that my raised beds didn’t “sink” as much as normal. In fact, I actually gained a little nutrient-rich organic matter! By having the Buckwheat shade the soil and then compost back into it, I mostly avoided the phenomena that causes soils high in organic matter, particularly ones exposed to the sun, to disappear over time due to breakdown by microorganisms.
Many cover crops are awesome attractors of pollinators and beneficial insects. At any given time while my Buckwheat cover was flowering, I could spot several wasp species, various bees, flies, moths, true bugs, and even a butterfly or two hovering around the tiny white flowers sipping nectar.
Covers are a lot prettier than bare soil and weeds! Where I would normally just have either exposed black compost or a healthy weed population to gaze upon, Buckwheat provided a quick bright green color blast that then became covered with non-stop white flowers. I’ll take that over bare soil any day.
Buckwheat cover before termination (left) and after (right) interplanted with Eggplant. Photo courtesy Daniel Leonard, UF/IFAS Calhoun County Extension.
Now that I’ve convinced you of Buckwheat’s raised bed cover crop merits, let’s talk technical and learn how and when to grow it. Buckwheat seed is easily found and can be bought in nearly any quantity. I bought a one-pound bag online from Johnny’s Selected Seeds for my raised beds, but you can also purchase larger sizes up to 50 lb bags if you have a large area to cover. Buckwheat seed germinates quickly as soon as nights are warmer than 50 degrees F and can be cropped continuously until frost strikes in the fall. A general seeding rate of 2 or 3 lbs/1000 square feet (enough to cover about thirty 4’x8’ raised beds, it goes a long way!) will generate a thick cover. Simply extrapolate this out to 50-80 lbs/acre for larger garden sites. I scattered seeds over the top of my beds at the above rate and covered lightly with garden soil and obtained good results. Unlike other cover crops (I’m looking at you Crimson Clover) Buckwheat is very tolerant of imperfect planting depths. If you plant a little deep, it will generally still come up. A bonus, no additional fertilizer is required to grow a Buckwheat cover in the garden, the leftover nutrients from the previous vegetable crop will normally be sufficient!
Buckwheat “mulch” after termination. Photo courtesy of Daniel Leonard, UF/IFAS Calhoun County Extension.
Past the usual cover crop benefits, the thing that makes Buckwheat stand out among its peers as a garden cover is its extremely rapid growth and short life span. From seed sowing to termination, a Buckwheat cover is only in the garden for 4-8 weeks, depending on what you want to use it for. After four weeks, you’ll have a quick, thick cover and subsequent mulch once terminated. After eight weeks or so, you’ll realize the plant’s full flowering and beneficial/pollinator insect attracting potential. This lends great flexibility as to when it can be planted. Have your winter greens quit on you but you’re not quite ready to set out tomatoes? Plant a quick Buckwheat cover! Yellow squash wilting in the heat of summer but it’s not quite time yet for the fall garden? Plant a Buckwheat cover and tend it the rest of the summer! Followed spacing guidelines and only planted three Eggplant transplants in a 4’x8’ raised bed and have lots of open space for weeds to grow until the Eggplant fills in? Plant a Buckwheat cover and terminate before it begins to compete with the Eggplant!
If a soil building, weed suppressing, beneficial insect attracting, gorgeous cover crop for those fallow garden spots sounds like something you might like, plant a little Buckwheat! For more information on Buckwheat, cover crops, or any other gardening topic, contact your local UF/IFAS County Extension Office. Happy Gardening!
