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.
Weed ID Links
Common, and aggravating, weeds.
How to Prevent Weeds?
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.
Weed Prevention Links
How to Control Weeds?
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.
Weed Control Links
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.
Species-Specific Control Links
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.
Many folks are giddily decorating their homes for the holiday season. For some outdoor enthusiasts and/or environmental educators, now is the time to collect and preserve a natural decoration, with care. Hornet nests offer a large natural ornament that can be used as a conversation piece or to teach people about an interesting native wasp that is often feared.
The face of a baldfaced hornet! Credit: Piccolo Namek, Wikimedia Commons.
The bald-faced hornet (Dolichovespula maculata) is a type of wasp closely related to yellowjackets, of which there are two species that are known from Florida, the eastern yellow-jacket (Vespula maculifrons) and southern yellowjacket (Vespula squamosa). The bald-faced hornet is different than its yellowjacket relatives in that it creates a large aerial nest rather than a subterranean nest. If you have seen a hornet’s nest in person, you know how impressive they can be. Surprisingly, they can be safely preserved for indoor display!
Hornet colonies begin each spring and are “founded” by a lone adult queen that made it through the winter, hiding under the bark of logs and such. The lone queen begins creating the papery brood cells and laying eggs. Once those eggs begin to hatch, the newly hatched all-female crew of hornets begin assisting in nest building and foraging while the queen shifts to only laying eggs. Towards the end of fall, some of the eggs receive more food (they become queens) and the queen also begins to lay male eggs. Once these emerge, they mate, and the cycle starts all over again, with the colony dying back, leaving an abandoned and impressive aerial nest behind.
The aerial nest of the baldfaced hornet. Credit: Preston Robertson, Florida Wildlife Federation.
To collect that impressive nest safely, wait until a couple of freezes have passed. At this point, most, if not all, of the hornets will have perished and that lone queen will be sheltering through the winter. Don’t wait too long since these nests are utilized by other wildlife and may be destroyed or get beaten up by the weather. Simply cut the nest off its support (realize it may be heavy). To be extra sure you don’t bring live hornets inside, you can leave the nest in a protected outdoor location, such as a garden shed or the garage, where it will be exposed to further cold temperatures. This also allows any “off” smells from rotting larvae to air out. Don’t worry about harming these larvae as they would starve either way since they must be fed by adult hornets! There is no need to use varnishes or polyurethanes for preservation as the nest will keep indefinitely as long as kept in a dry environment free from a lot of handling or vibrations.
Bingo, you now have a natural ornament that can last through many seasons and provide for learning opportunities and lots of conversation!
For more information on wasps, including hornets and yellowjackets, please see the Yellowjackets and Hornets EDIS document from UF/IFAS. Information from Iowa State University’s website Preserving and Displaying a Hornet’s Nest was also used to help write this article.
As a compost fanatic, one of my favorite Florida-Friendly Landscaping principles is Recycle Yard Waste – Principle #7. Since the practice of gardening typically leads to various debris, including herbaceous weeds, lawn clippings, woody stems after pruning, and just the leaves that fall from your trees, gardeners must somehow manage all of this material.
Rather than tossing it to the curb, where it goes to the landfill and very slowly breaks down in anoxic conditions (lacking oxygen) leading to increased methane emission, a more sustainable approach is to utilize these materials on site. On-site recycling of garden debris can be done through, my favorite, composting, especially when dealing with herbaceous material.
Grass clippings are best left on the grass, as long as not in excessive clumps. Woody debris can be piled in not-too-conspicuous areas to create brushpiles that will provide wildlife with cover. While many think of snakes and other creepy crawlies in piles of brush, many birds, lizards, mammals, insects, and fungi will call a brushpile home. Fallen leaves can be raked into garden beds to act as mulch, another Florida-Friendly Landscaping principle! Besides not using the energy required and creating the extra methane (a stronger greenhouse gas than carbon dioxide) produced by sending materials to the landfill, recycling materials on-site returns the nutrients in that debris to your soil for future plants to take up.
However, there is a fate of yard debris that is even worse than sending to the landfill (cue scary music) – illegally dumping the materials in a natural area!!
Landscape debris dumped in a natural area can spread invasive plants, insects, and disease. Credit: Mark Tancig.
You may have seen this in a local natural area you visit or heard of folks that try to skip paying solid waste fees by dumping it elsewhere. Unscrupulous landscape companies and homeowners have been known to do this, especially when the work site is near a large natural area, such as a state or national forest. The main problem with this, besides that it is illegal, is that invasive species can be spread with debris directly into a native forest. Invasive plants are documented to be spread in this manner, especially those that are easily rooted from stems. Additionally, illegal dumping of plant material can spread non-native fungi, insects, and animals into these areas and disrupt natural ecosystem functions and the organisms that rely on them.
Not only is illegal dumping bad for our natural areas, but it’s illegal! Credit: Mark Tancig.
Homeowners can make sure they don’t contribute to this problem by recycling as much on-site or properly following local guidelines to dispose of landscape debris. Many municipalities have separate bulk collections or drop-off sites for landscape materials. If hiring a landscape contractor, ask where they take the collected material and/or request that it stay on the property. For large jobs, such as tree removal, the estimate should reflect dump fees. If you notice materials dumped in a local natural area, report it to the land manager so they can investigate and/or clean it up and dispose of properly.
North Florida vegetable gardeners have made it to summer and now the plants and gardeners are starting to give in to the heat and humidity. The squash has likely succumbed to squash vine borers, many of the tomato varieties are having trouble setting fruit, stink bugs are all over, and gardeners easily wilt by noon. This is a good time to use our oppressive heat to your advantage in the vegetable garden by solarizing the soil.
We have reached the peak of heat. Use it to your advantage in the garden. Source: National Weather Service.
Soil solarization is a method of pest control that creates a greenhouse to heat up the soil in an effort to drive away pests. Pests that can be reduced with soil solarization include weeds, various soil-borne fungal pathogens, and nematodes. Weed seeds can actually be killed by the increased temperatures, sometimes as high as 140 degrees Fahrenheit, while fungi and nematodes are merely driven deeper into the soil layer as they try to escape the heat. Although they are not killed, this can help vegetable gardeners as it may take these organisms 3-4 months to repopulate in high enough numbers to cause damage. Soil solarization can be considered another tool in your integrated pest management (IPM) toolbox, along with other cultural, physical, and chemical means of pest control.
A raised bed being solarized over the summer. Source: Evelyn Gonzalez, UF/IFAS Master Gardener Volunteer.
To properly execute soil solarization, the site should be in full sun and the existing vegetation removed, either by hand or with a tiller or other implement. Tilling can help loosen the soil surface and allow heat to penetrate deeper in the soil horizon. Before being covered with plastic, the area should receive rainfall or be irrigated, as the water will help conduct heat to greater depths. The next step is to cover the area with plastic. Note that this can also be done over raised beds! Clear plastic is best for maximum solar radiation penetration. Black plastic will heat up mostly on the surface and opaque plastic sheeting may not let enough light in to get temperatures high enough. The plastic should be slightly larger than the area covered, as the edges will need to be buried to create an air-tight seal. It’s recommended to leave the plastic in place for at least six to eight weeks, just in time to begin fall gardening preparations.
It’s important to monitor the site while it’s “cooking” to look for any holes that might appear. Small holes can be repaired with duct tape, while large holes or rips in the plastic may require starting over. Overlapping strips of plastic is not recommended since too much heat will be lost.
You may be wondering what happens to all of the good soil microbes. Well, unfortunately, they are also either killed or suppressed. Fortunately, researchers have found that they are able to repopulate quicker than the pest organisms, especially in soils with a good amount of organic matter.
Much more information on soil solarization can be found in these two documents:
Introduction to Soil Solarization – https://edis.ifas.ufl.edu/pdffiles/IN/IN85600.pdf
Solarization for Pest Management in Florida – http://edis.ifas.ufl.edu/pdffiles/IN/IN82400.pdf
Also, please contact your local county extension office for more gardening tips.
Symptoms of oak leaf blister on swamp chestnut oak. Credit: Gordon Magill.
Even during global pandemics, it’s a joy to be outside during the great north Florida spring we’ve been experiencing lately. As cold fronts come through with their rain bands, some packing a punch, they leave behind the most pleasant mornings, clear blue daytime skies, and crisp evenings. Unfortunately, we’re not the only organism that also enjoys those cool days. Many species of fungi are quite active this type of year as the rains, followed by warmer, yet not too hot temperatures, create the perfect conditions for fungal growth. Some of these fungi grow right on or in the plants we’d like to be enjoying for ourselves, stealing nutrients and causing plant decline or merely causing aesthetic damage. As this is an active time for certain species of fungi, local extension offices are getting more calls and questions regarding lawn and landscape damage due to fungal pathogens. A recent call was a new one for me and an example of a native fungi-plant interaction that looks bad but requires no intervention from us. It also highlights how correctly identifying a disease leads to the best action and can often save time and money and prevent unnecessary pesticides (in this case a fungicide) from entering the environment.
Close up of oak leaf blister on swamp chestnut oak. Credit: Gordon Magill.
The fungi and plant involved here was the oak leaf blister (Taphrina caerulescens) on a swamp chestnut oak (Quercus michauxii). It forms, you guessed it, blisters on the leaves of any of the oaks, though live oak (Quercus virginiana), laurel oak (Quercus laurifolia), and water oak (Quercus nigra) seem to be preferred hosts. The spores of the fungi, dormant since the previous summer/fall and which happen to get lodged in bud scales through wind and rain, germinate in cool, wet weather. The fungus then infects young leaves as they flush and its growth causes a disruption in the leaves’ development. This leads to the blistered look of the leaf tissue and, during extended periods of cool, wet weather, the entire leaf sort of shrivels, browns, and eventually falls off. Spores are eventually released from the fallen leaves to start the process over the next spring.
Severe oak leaf blister on swamp chestnut oak. Credit: Gordon Magill.
Though the leaves look pretty terrible, this fungal disease rarely causes plant health issues and the tree recovers just fine. Specimen trees that experience it year to year may be treated with a fungicide, but most homeowners can just let it go. Raking up and disposing of the leaves may help prevent further infections by reducing the number of spores released in the area.
As you enjoy another cool morning after an evening rainstorm, remember that the fungi all around you are also having a great day. You may want to look at your landscape plants and see if there’s anything abnormal going on. If so, take a photo and send it to your local extension office for help with identification and best methods of control, or, like in this case, just leaving it alone.
p.s. As I said this was a new one for me and I want to thank Stan Rosenthal, Extension Agent emeritus, for assisting with identification.