After a relatively cold winter like the Florida panhandle has experienced the last couple of years, it’s always gratifying to see plants greening up in the spring. Anyone who enjoys the outdoors is likely to want to get out there and start helping things grow. That means it’s time to get the irrigation system up and running every day, right?
Probably not!
The conditions in our region can be harsh on plants. The soils are very sandy, meaning they don’t easily hold on to water or nutrients for plants to use. The weather ranges from freezing cold in the winter to sizzling hot in the summer. Rain might come down in 20-inch bursts or not at all for weeks at a time.
With all these challenges plants face, it’s very important to choose ones that can handle all that our environment throws at them. Native plants and those designated as “Florida Friendly” tend to be well suited for our location, but they still may need some care. They must be placed in the correct location in the landscape based on their needs for sunlight, water, and other factors. If you choose the right plant and place it in the right location, you’ll drastically reduce the amount of management that it needs on an ongoing basis. This includes watering.
While actively growing, plants – whether that means towering trees or low-growing grass – take up water through their roots and give some off in the form of water vapor through their leaves. If the amount of water in the soil is more than the plant is giving off, it doesn’t need more! Watering at these times can actually harm, rather than help. The roots of overwatered plants typically start to die back, which can lead to symptoms such as patchy dieback of foliage or what may look like nutrient deficiency. Overwatered areas might also see an uptick in water-loving weeds such as dollarweed, which will be difficult to control unless the area is dried out a bit.
Set irrigation systems to water early in the morning rather than at midday, and make sure they water plants, not walls.
It is tempting to think that our sandy soils drain quickly enough to make watering a constant necessity, but remember! We’ve already chosen plants that survive well in our location. Even our turfgrasses are chosen for their ability to withstand drought. There may only be three or four months out of a year that become dry enough to warrant extra irrigation at all, and even then, it’s probably less than most people expect!
For lawns, a general rule is to water only when the grass is showing signs of drought stress. Leaf blades may fold up lengthwise, the lawn’s color may become duller, and footprints in the turf persist rather than springing back. If the turf needs watering, apply ½ to ¾ inch of water per irrigation – that’s all!
Improperly calibrated irrigation systems can do more harm than good.
To figure out how much that is, set several small, empty straight-edged cans such as cat food tins or tuna cans out in the lawn. Run the irrigation for a set period of time to see how much water collects. This will also highlight any inconsistencies in watering, so you can try to adjust your irrigation system to water evenly by replacing broken nozzles and making sure the whole area is covered with no gaps or overlaps. Make sure the irrigation system is equipped with a rainfall shutoff device as well, to automatically stop watering when it rains (which it often does regularly).
Overwatered shrubs may display patchy dieback or yellowing leaves.
For landscape plants such as trees and shrubs, you may not need any supplemental irrigation at all unless there is a severe drought. Know your plants’ needs and keep an eye on the weather. Droughts, if we do have them, usually occur in the spring or fall in our area. During the summer, daily rainstorms often allow us to keep our irrigation systems off for months at a time!
Water appropriately and you may notice a reduction in your water bill, fewer plants that need to be replaced, and fewer water-loving weeds. You’ll also help the environment by reducing runoff into water bodies.
For more information on watering, contact your local Extension office. There is also a wealth of information to be found online, with resources such as the Florida Friendly Landscaping program and UF’s EDIS publications (see “Watering Your Florida Lawn”, for example). Happy watering!
It has been dry as a bone lately, and your landscape is beginning to reflect that fact. Before you call it the dreaded “D” word you should understand that these dry periods are part of our yearly weather cycle. This year, we are drier than usual which means we are indeed in a drought. This can be alarming as you’ve doubtless spent tons of time and money on your landscape and want it to thrive. Irrigating as much as possible may seem attractive but is not necessarily the best strategy. Let’s first look into a few questions. What happens to your plants when Mother Nature turns off the waterworks? What can be done to prevent the mass die-off of our landscape plants?
Drought Response
Before we delve too deeply into the subject, it’s worth taking a few lines to discuss what happens to plants in periods of drought. Many will close the tiny pinpricks in their leaves known as stomata to prevent water loss. This is known as a drought avoidance strategy, and while seemingly foolproof also prevents moisture absorption while shutting down photosynthesis. If this condition persists, the plant will begin to lose the macronutrient carbon and sugars. When a lack of water becomes long term, the plant will perish as it lacks resources.
UF/IFAS photo: J. Criss
Other plants utilize a drought tolerance strategy. Unlike the avoidance strategy, these plants leave their stomata wide open despite the lack of moisture in the soil. The advantage here is that photosynthesis never stops. They’re banking on a return of water before they perish from dehydration. Most of your landscape plants utilize the first of these strategies. Your gardening habits and strategies are crucial to keep your plants thriving even in our extreme heat.
Gardening Practices
The practices you implement in your gardens are what we refer to in this business as “cultural practices.” You may have heard of these at lectures on Integrated pest management, but they are just as applicable in landscape management.
Irrigation is easily the most crucial of these practices as improper watering is the number one killer of plants. Deeper watering delivered less frequently encourages deeper rooting and higher drought tolerance. Irrigation should occur early in the morning just before sunrise to prevent evaporation and mitigate fungal issues as plant water use begins at sun rise. Frequency and volume are the next critical factors in watering. Turf grasses need 1/2 to 3/4 inch of water, but only when they present the three signs of wilt including folded blades, a bluish-grey hue, and lingering footprints. Bedding and landscape plants are a little trickier as they don’t have standardized signs of wilt. You’ll need to pay close attention for loss of vigor in the leaves which are likely to be subtle. When these signs present, apply enough water to reach their root zone. A great way to extend the time between irrigation events is to amend soils with organic matter and to utilize mulch. These retain moisture keeping your plants less thirsty.
UF/IFAS Photo T. Jones.
Fertilization can be another far more detrimental to plant growth than you think. While it’s true that your plants need nutrition for vigorous growth, only those deficient in the soil are limiting factors. This is simply not possible to create a fertilization strategy without soil testing. Your extension office can facilitate testing, which should occur at a minimum every three years. Balance these deficiencies with your plant’s needs to create a healthy landscape.
Pruning is the final practice to look at for healthy landscapes. Turfgrasses need to be cut at a height conducive to their growth. This varies for each grass type, so make sure you know yours. Landscape plants may also need species specific pruning practices such as deadheading to maintain healthy growth.
To Sum Up
The key takeaway from this article is that stress free plants are more capable of tolerating less than ideal growth environments. Familiarize yourself with the needs of your plants and provide them with what they need to thrive. Very often this means less intensive maintenance practices. For more information, see this Ask IFAS document, or contact your local extension agent for additional information on this and any topic regarding your gardens and more.
It has been a hard summer climate wise and as we go into fall it is nice to start getting some relief from the heat. As the heat tones down, we are still facing a drought, which is not as severe as areas to our west but is still significant across much of the Panhandle. In our tree cover, the stress from the harsh summer this year is starting to show. You can see it in trees around the area, and it particularly seems to affect certain trees and conditions more than others. Where you are starting to see it most is in our ever-present pines, which make up the majority of our forest and tree cover in our region. If you keep a look out you may notice some pines in the areas with yellowing or brown needles or that are losing their needles. Those are clear signs of a possible bark beetle attack, which is a common issue when pines are stressed or damaged. Trees planted in the last year that are not yet fully established often show stress in a hot dry summer like this year. Even older and well-established trees in areas are showing some signs of stress from the hot dry conditions we have had this summer. Some trees are less adapted to dryer areas and when planted off site can experience more stress in dry conditions. If you look around across the Panhandle right now you can see clear signs of stress in some trees. It becomes more evident in late summer and early fall as the accumulated stressors of summer push trees into physiological conditions that cause stress responses. The big question is what to do if you notice a landscape tree that is exhibiting signs of stress, particularly drought stress.
Pine damaged by construction equipment. Barking injuries like this can encourage bark beetle attacks. Photo Credit: Ian Stone
For pines the issue is likely to be bark beetles, of which there are several types. All pine bark beetles are native to our area and the degree of damage they do varies by species and conditions. The issue with stressed trees is that most bark beetles attack those trees. When a hot dry summer occurs bark beetle activity increases as the stressed trees become less able to fend off attacks by these beetles. Unfortunately, when bark beetles attack a pine in an area the best answer is prompt removal and disposal of the infected tree material. To protect high value trees in an area where bark beetles are active there are some injection pesticides that can prevent infestation, but once a tree has been infested and begun to show symptoms little can be done to bring it back. When bark beetles attack a stressed pine, most are effectively finishing off a tree that may have died regardless. The key is to prevent them from spreading to other pines in the area or attracting them to a stressed tree in an area. With trees already stressed in our area the big prevention option is not to damage or stress any pines already on the landscape. Most pine bark beetles are attracted to trees by chemicals in pitch and resin given off by wounds or damage. Often the stress from new landscaping projects or construction around pines can cause several to succumb to bark beetles. Your best prevention is to keep equipment well away from the tree and avoid damaging or injuring the tree, especially scraping areas of bark off. Larger and older trees can be vulnerable, as well as overcrowded trees that are too dense or overtopped by others. As the cooler weather approaches bark beetle activity should decrease along with the risk of losing a pine to these pests.
Recently constructed sidewalk. Construction activities extended well into the root zone of the tree, which can cause stress and damage. Photo Credit; Ian Stone
For other trees there are additional precautions that can be taken to lessen the potential that a tree will succumb to drought and other stress. Newly planted trees or those established in the last several years are particularly at risk and should be watered regularly during this dry period. Until rains return, a good method of slowly applying water deeply to the root zone is best. Properly applied mulch can help keep the soil cooler and moist around a newly planted tree. Drip irrigation, soaker hoses, and similar methods are best, and a method that specifically applies water slowly to the tree’s root zone gives the best results. Watering your lawn does not supply sufficient water to landscape trees, especially in drought conditions. Lawn irrigation is designed to apply irrigation needed to the top portion of the soil that is available to the grass. Trees have completely different requirements and need different watering methods and amounts. If you don’t have dedicated irrigation available and you have a tree that needs water, you can use irrigation donuts or bags. These are often a good solution for a tree that needs watering temporarily. Once a tree is well established it usually can withstand even severe drought, but during the establishment phase paying attention to water needs is critical in a summer drought like we have had.
Large established trees are also not immune from the heat and dry conditions that have plagued the Panhandle this summer. Usually when conditions change these trees recover but may abort some branches or exhibit some leaf drop while stressed. Leaf drop is a phenomenon that can occur when deciduous trees are stressed. It is a method of conserving water needs by reducing the leaf demand. Usually, the tree will recover and leaf out again fine next year. A tree may abort some branches or have some branch tips die back to make it through a rough period. Trees that are overcrowded, overtopped, or have other issues are the most at risk from environmental stress. This is why good tree selection along with proper tree care and maintenance is essential. When a hot dry summer like we have had comes along well cared for and maintained trees do best. Trees that prefer more moisture like bald cypress, red maple, sycamore, and some oaks can be planted in dryer sites, but when a severe drought comes along they often don’t have the ability to handle the moisture stress that trees adapted to dryer sites can. This is why site selection is so important, it is when we have extreme conditions that off site plantings typically suffer the worst and those can be larger more established trees.
With the cool weather hopefully we will get a reprieve and some rain soon. Given that fall is one of our dryer periods it may be likely that drought conditions could persist until early winter. Good care and tree maintenance is essential to getting your trees through stressful periods like this summer. For younger trees watering and care is essential while they get established. For older established trees avoid doing any construction or other disturbing activities around them until conditions improve. If you have trees that are exhibiting signs of decline or pest attacks call your local extension office or Florida Forest Service County Forester office. With any luck, colder weather with winter rains will be here soon and trees in our area will recover over the dormant period.
Fertilization is a subject that throws many a gardener for a loop. It can be confusing, and we in the professional horticulture world understand. This topic will almost always be approached from the prospective of nitrogen. So why does nitrogen get so much attention? What is its role in plant growth? Nitrogen is the primary driver of protein synthesis, plant metabolism, energy creation, and is the structural component in chlorophyll. These are all extremely important functions leaving little doubt as to why it’s so critical. Your plants use this resource abundantly for healthy growth. The reason it gets so much attention is owing to its frangibility in the soil. Nitrogen goes through changes once applied to soils and is readily lost to the environment. For this reason, nitrogen application needs to be timed appropriately, and your cultural practices need to be such that encourage plant uptake over losses to the environment. Fear not my friends, this article will bolster your insight into the wonderful world of nitrogen, and have your plants growing strong and healthy.
The What and Why of Nitrogen
Nitrogen is one of three macronutrients identified in every fertilizer bag as the first of three numbers. This standardized NPK labeling refers to the amount of this nutrient in the bag by percentage of total weight. Application rates should be based on this number, and how much nitrogen you’ll need to cover a specified area. which number you use is based on the equipment you have to apply more so than the plant requirements.
UF/IFAS Photo: Dan Culbert
Nitrogen can be natural or man made. Natural sources come in the form of composts, manures, and through atmospheric deposition. The later of these sources means rain, which washes nitrogen out of the atmosphere and into your soils. Man made sources conversely come in bags and are the result of a combustion process developed by Fritz Haber, and Carl Bosch circa 1910. Either way, nitrogen will be in the form of ammonia, nitrate, ammonium, or urea. Knowing this is important as it will dictate application methodologies. For instance, urea applied to the surface will escape into the atmosphere if not incorporated into your garden.
UF/IFAS photo: T.W. Shaddox
Nitrogen type will also affect soil pH. This is especially important with ammonia-based fertilizers as residual acidity from them may lower pH. Applying the correct type will mitigate large unwanted changes in soil. Why are we concerned with soil pH? It speaks to nutrient availability and, thus how well your plants grow. It can be overwhelming, but with soil testing and a call to your extension office, it’s easy to identify the appropriate fertilizers for your application.
Reactions in Soils
Soil is often considered inert, holding plants in place while providing a pantry full of the nutrients they crave. Nothing is further from the truth. Soil is a living entity with its own physical and chemical properties. The addition of anything, including irrigation, affects these properties.
Nitrogen takes two forms in your soil aside from nitrogen source. Inorganic nitrogen is converted from soil organic matter in a process known as mineralization or added from bagged fertilizers and is available for plant uptake. Organic nitrogen is unavailable for plant uptake and will be present in the natural forms listed in the previous section. Both are susceptible to the nitrogen cycle and may be lost to the environment. This happens as water passes through soil (leaching), erosion, runoff, or is lost to the atmosphere through volatilization and may have negative effects on surrounding water bodies.
UF/IFAS Photo
To mitigate these risks through responsible fertilizer application, irrigation management, and landscape design. Apply fertilizers when plant uptake is favorable, and only to the level required by your plants. This will be during heavy vegetative growth periods such as initial installation. Irrigate as dictated by your plant life vs on a timer. Watering is a vital practice, but often overdone. Keep water levels enough to avoid plant stress but not excessive. Doing so reduces leaching potential and will keep your plants healthier. Finally, design your landscape with Florida Friendly Landscaping principles. Integrate diverse plant life, including turfgrasses and landscaped beds. The goal here is to allow enough plant life to absorb excess storm water, and support local pollinator populations.
Nitrogen is a critical piece of your fertilizer routine. It’s important to understand how it reacts with both your plants and your soils. A little knowledge can go a long way to keeping your plants healthy while mitigating risks from over fertilization. For more information, see this Ask IFAS document, or contact your local extension agent for additional information on this and any topic regarding your gardens and more.
It amazes me that even under flood conditions, people still water their lawns.
I’m sure you’ve seen it too – we get enough rain to cause some areas to flood and yet you see irrigation systems going full blast.
Lawn irrigation should be applied on an as needed basis. Credit: Larry Williams
We should water our lawns, landscapes and gardens on an as-needed basis. The way that some people water their lawns is as logical as saying that a pet dog needs a drink of water at 4 p.m. everyday. This is not true. When watering, we are simply replacing water that is lost. This is true when we drink water ourselves, when we provide water for a pet dog, or when we provide water for our lawns, landscapes and gardens.
An irrigation system is a great tool when used to supplement rainfall. Irrigating too much not only wastes water but it also is the cause for many lawn problems such as shallow, weak root systems, leaching of fertilizer and numerous lawn diseases. Cutting the irrigation timer to off and operating the system manually will solve many lawn problems.
Also, there are tools to prevent an irrigation system from coming on during rain or when adequate rainfall has occurred. As a matter of fact, it has been state law in Florida for every automatic irrigation system to have a rain shutoff device installed since 1991.
Florida Statutes, Chapter 373.62 – Water conservation; automatic sprinkler systems states, “Any person who purchases and installs an automatic lawn sprinkler system after May 1, 1991, shall install a rain sensor device or switch which will override the irrigation cycle of the sprinkler system when adequate rainfall has occurred,”
Rain sensors are available, inexpensive and are not difficult to install. Rain shutoff devices really do work when installed properly. If you do not feel qualified to install such a devise on an existing system, check with a reputable irrigation company.
Water only when lawn indicates that water is needed. When the grass needs water, leaf blades fold along the midrib – like a book closing, footprints remain in the lawn long after being made and the lawn turns grayish in spots, indicating it needs water.
When 30 to 40 percent of the lawn shows these signs of water need, turn the irrigation system on and let it run long enough to apply one-half to three-quarters inch of water. Don’t water again until the lawn begins to show these signs of water need. Watering this way will develop a deep-rooted lawn and landscape. Here’s a UF/IFAS Extension link with more information on lawn and landscape irrigation. https://gardeningsolutions.ifas.ufl.edu/care/irrigation
