by Beth Bolles | Sep 16, 2015
Just when you think your battle against weeds is over for the summer, cooler nighttime temperatures and shorter days spark the beginning of a new crop of your least favorite plants. The question of many homeowners is: how did all the weeds get into my landscape?
There are many ways that weeds make it to the landscape. They can be brought in with new soil, mulch, container plants, dropped by birds, delivered on the fur of animals, carried by wind, or on the deck of a lawn mower. If that is not enough to depress you, then also realize that regardless of outside sources of weeds, your landscape already has plenty onsite that you don’t even know about.
In the soil, there is a large number of weed seeds ready to germinate when the conditions are just right. Understanding how your common landscape practices can encourage or discourage the germination of these seeds, can help you begin to manage some weed infestations.
Many of the seeds of common annual weeds are very small. They require exposure to sunlight in addition to the proper temperatures and moisture to germinate. Sunlight is critical, though, and seeds will not germinate without adequate sunlight. If the small seeds are deep in the soil, you will probably never know they are there. When you turn soil or disturb soil such as when installing plants, you bring the small seeds close to the surface and closer to light. They can then be stimulated to germinate. The next thing you know, you have an area covered in weed seedlings.
As mulch thins, small seeds of weeds are stimulated by sunlight to begin growing.
What does this mean for your gardening practices? Try your best to block sunlight from hitting exposed soil. You can do this by keeping a healthy turf, free of thinning spaces. A 2 to 3 inch layer of mulch in plant beds and vegetable gardens will reduce weed seed germination. Finally, when you are installing plants in an established bed, try not to mix soil with surrounding mulch. Seeds will easily germinate within the mulch if it becomes mixed with soil.
It is inevitable that your landscape will have some weeds but a few easy gardening practices can reduce some of your weed frustrations.
For more information:
Gardening Solutions: Weeds and Invasive Plants
Improving Weed Control in Landscape Planting Beds
by Les Harrison | Aug 11, 2015
Weeds are growing everywhere, especially in manicured lawns and landscapes despite the best efforts of owners who have spared no expense to remove the offending flora. Herbicides to control the weeds seem to be less effective as August progresses.
The reality, at least about the herbicides, is different from perceived appearances. Herbicides can be a wonderful tool for the homeowner, if applied properly.
[important]The first point to remember about herbicides is to always, Always, ALWAYS apply them as instructed by the label directions. The oft quoted mantra of “the label is the law” is accurate.[/important]
Herbicides and their labeling are periodically reviewed and assessed to confirm effectiveness against target weeds without damaging the environment. Not following the label directions can have many negative implications for both the environment and the applicator.
Herbicides are either selective or non-selective when killing plants. Non-selective herbicides kill or damage every plant, but selective herbicides target a narrower range of plants.
Chamberbitter, a common annual weed. Photo credit: Mary Derrick, UF/IFAS Extension.
Never apply herbicides when there is a breeze or wind. Herbicide drift can injure or destroy plants that are not the intended target.
High temperatures can contribute to the drift problem by volatizing some of the herbicide spray. Even the lightest air movement will cause drift off the target weeds when this condition exists. Herbicide drift can also be deposited in ponds and streams, harming the aquatic creatures that live there. Some herbicides are toxic to fish, insects and other animals that can be killed by tiny amounts of the active chemical. Additionally, the off target herbicides can kill aquatic plants. When the dead plants decay, they deplete the water of oxygen, again threatening or ending the life of the water’s residents.
Rain or dew resulting from high humidity can negate a herbicide’s application. If a leaf is wet, most or all the herbicide will run off on to the soil where it can leach into the water table.
Unless stated on the label, herbicides work only when the plant is actively growing. A hot, dry week or two can put a plant in drought mode, suspending growth and the herbicide’s effectiveness.
Many weeds have already produced seeds for next spring. Herbicides applied now will not affect the germination of that seed months from now.
The most effective strategy is to mow weeds before they set seed or to collect and destroy those which have already produced seed. Even with 100 percent success at eliminating this year’s weed seed crop, there will be weeds next year.
Some weed seed remain in the soil, sometimes for decades, only to germinate when conditions are perfect for their sprouting. Sickle pod and crotalaria are local examples of long term seed vigor.
Other seed can blow in or be dropped by wild or domestic animals passing through the property. A pre-emergent herbicide which stops germination can help control these latent invaders.
For more information:
Weed Management Guide for Florida Lawns
Gardening Solutions: Weeds
by Les Harrison | Feb 24, 2015
Smilax is noted for its multiple thorns which scratch anyone who comes into contact
The yo-yo thermometer readings make it confusing for the panhandle’s human residents when choosing proper wardrobe selections. With few exceptions, the deciduous plants and trees continue to wait for consistently warmer weather and longer days before covering their trunks and stems with foliage.
The current season’s uncloaking allows for easy examination of the structure and configuration of what will be green and hidden in a few months. This exposure also reveals potentially painful hazards in the native landscape.
Smilax, the sinewy vine, puts up an intimidating barrier to man and beast. Also known as green briar, cat briar and other sometimes graphic terms, the native plant thrives in this area.
In Greek mythology, Smilax was a wood nymph who was transformed into a bramble after the unfulfilled and tragic love of a mortal man. Her final form in this fable was a reflection of her character.
Botanically, smilax is found in tropic to temperate zones. There are about 350 species worldwide and 12 in Florida, with nine being common.
The plant is very vigorous and is equipped with an enviable array of survival traits. It is ready to take every advantage to flourish and inhabit new territory, even under the most unfavorable conditions.
Individual plants can withstand harsh treatment and environments. If burned or mowed to the soil’s surface, they will regenerate from a segmented rhizome root system. Rhizome roots are the subterranean stems which spread roots and runners from its bulbous root nodes.
If pulled up, the rhizome root system will separate at joints. Even the smallest piece of root left in the dirt will generate a new plant.
Smilax has the additional resource of extra-floral nectaries, nectar-producing glands physically separate from the flowers. These nectaries may function as an organ for the plant to rid itself of metabolic wastes and/or to attract beneficial insects for pollination and defense.
Ants are especially attracted to the extra-floral nectaries in smilax and frequently establish mounds close by. The ants defend the smilax from herbivores which eat the leaves, if they can get past the thorns.
In addition to spreading by its root system, smilax produces berries which contain a seed. The berries appear in late summer or early autumn and ripen to a blue-black color.
The berries are usually consumed in winter after the smilax loses it leaves. Birds and animals will deposit the seed at a new site. Best chances for the seed to germinate occur after it is exposed to a freeze, as the panhandle has recently experienced.
Smilax vines will climb up trees, fence post, and any other stationary object to get better sun exposure. They have been known to reach over 30 feet in height, but do not tend to kill their host by shading out the sun.
Ants commonly use the vines as a readily available pathway on foraging trips. Ants may establish colonies in above ground locations, courtesy of smilax vines which provide a wide-reaching pathway.
Smilax can be controlled with some broadleaf herbicides, but repeated applications will be necessary. The best time to apply herbicides is in the early spring when the first leaves appear.
Once the leaves return, smilax can be difficult to identify and control, hidden in all the common greenery.
To learn more about smilax in Panhandle Florida read the Key to Nine Common Smilax Species of Florida or contact your local UF/IFAS Extension Office.
by Mary Salinas | Feb 2, 2015
So often, homeowners wait until weeds have overtaken their lawns in mid-summer before looking for a course of action to control them. Unfortunately, when weeds get to maturity and start producing flowers and going to seed, they are usually quite difficult to control.
[important]The best strategy is to prevent the weeds from getting established in the first place![/important]
Florida pusley, an annual weed that can be controlled with preemergence herbicides. Photo credit: Mary Derrick UF/IFAS Extension.
When properly applied, a preemergence herbicide forms a chemical barrier on the surface of the soil that kills newly germinated seeds when they grow and contact that barrier. Be sure to follow label directions carefully as it is crucial to apply the correct amount and water it in correctly. The soil surface should not be disturbed after application to ensure that the chemical barrier remains intact.
Keep in mind that preemergence herbicides only prevent annual weeds! They do not control weeds that have already emerged.
In North Florida, the time to apply a preemergence herbicide to your turfgrass is coming soon. As a general rule, March 1 is an ideal time. Another indicator that the time is right is when the daytime temperatures reach 65°F-70°F for 4 to 5 consecutive days as that sustained warmth will prompt weed seeds to germinate. Oftentimes, this is also when azaleas or dogwoods start blooming and that can clue you into when to apply the herbicide. For best results, follow up with a second application in 6 to 9 weeks to control those seeds germinating later in the season.
Always follow the label instructions precisely when applying any herbicide! Ensure that you apply the product at the correct rate, that it is suitable for your specific turfgrass and situation, and that it is watered in correctly. For any pesticide, the label is the law!
If your lawn has problems with winter weeds, make a note on your calendar to apply a preemergence herbicide about October 1 in North Florida or when nighttime temperatures drop to 55°F-60°F for several consecutive days.
For more information on weed control in lawns:
Weed Management Guide for Florida Lawns
For general information on lawn care in Florida:
UF/IFAS Gardening Solutions: Lawns
by Larry Williams | Jul 15, 2014
Florida Betony (Stachys floridana), commonly called rattlesnake weed, is a Florida native plant. It’s thought to have been confined to Florida until it was moved to other Southeastern states during the 1940s or 1950s in nursery containers. It is now found from Texas to North Carolina. Its square stems are characteristic of the mint family of which it is a member.
Florida Betony foliage & flowers Photo Credits: UF/IFAS Extension
Underground white, fleshy tubers, which resemble a rattlesnake’s rattle in shape, provide the main means of reproduction. Pinkish-purple flowers are followed by a dried fruit that splits open releasing tiny seeds, which are a lesser means of reproduction. The white tubers have been used for hundreds of years as a starchy vegetable and are sometimes boiled like peanuts.
Florida betony weed tubers Photo Credits: UF/IFAS Extension
The tubers make Florida Betony tough to control. Even when above ground foliage and stems are killed due to herbicide use, the tubers allow the regeneration of the plant repeatedly. When attempting to control this weed, it helps to be more persistent than the plant. Many people give up.
Even though it is a perennial, the above-ground portion of the plant grows during fall and spring and becomes dormant during hotter weather.
You can remove the weed by digging, making sure to remove the entire root system (including the tubers). But persistence and patience is required. Herbicide control usually involves repeat applications approved products in lawns. Glyphosate herbicides such as Roundup can be used to control Florida Betony in plant beds. But do not get the herbicide on any green portion of desirable ornamentals.
Always refer to the product’s label for specific uses, application rates and turfgrass tolerance when using any herbicide.
So, why not just dig up the Florida Betony in your lawn and have a native plant feast?
by Larry Williams with content by Matthew Orwat
by Larry Williams | Jul 8, 2014
Making cut before herbicide application Photo Credits: Larry Williams & Sheila Dunning, Okaloosa County Extension Agents
Question: We planted Wisteria for its beautiful spring flowers and it grew and grew and took over everything. Now we’re trying to get rid of it. New plants are sprouting everywhere – up to ten feet away from the original plant. Is there a way to rid our landscape of this now wild plant?
Answer: Chinese Wisteria, Wisteria sinensis, can be a big problem to control. I’ve seen entire fields taken over by it. Yet, many people wonder why you would want to kill a beautiful plant like Wisteria. It’s possible to keep it in bounds for a while (possibly years) in the middle of a lawn with its new shoots arising from roots being routinely mowed. But in many cases, given enough time, shoots coming from roots will escape and then begin to take over – growing on adjacent property, climbing trees, etc.
Application of triclopyr herbicide to cut stump Photo Credits: Larry Williams & Sheila Dunning, Okaloosa County Extension Agents
In order to control an established vine, you must be persistent. Your best bet, outside of moving, is to use a “cut stump” treatment on the main plant and every shoot that sprouts. Use a herbicide that contains triclopyr. Some brand names include Enforcer Brush Killer, Ortho Brush-B-Gon, Ferti-lome Brush Killer-Stump Killer. Cut the main stem (trunk) as close to the ground as possible and as level as possible to facilitate application of the herbicide to prevent sprouting. It is critical to immediately apply the product to the freshly cut “stump.” Stumps that are not treated with the herbicide will sprout. Always follow label directions and precautions and be very careful to not get the product on adjacent desirable plants, including their roots.
Other invasive, undesirable woody plants can be controlled using this method such as Chinese tallow (popcorn tree), Chinese privet (Ligustrum sinensis) and Japanese honeysuckle (Lonicera japonica). For more information, view “Herbicide Techniques for Woody Plant Control”, from UF IFAS Extension .
