by Les Harrison | Jan 20, 2016
North Florida’s gardeners are facing a new set of challenges dealing with the effects of cold weather. However, a little planning and creativity can make plant protection in the landscape a relatively simple process.
Covering plants to protect from frost. UF/IFAS Photo: Sally Lanigan.
Many homeowners and landscape managers want to know when plants will need protection. The point of freezing is a good rule of thumb for most temperate zone plants.
It is worth noting there is a difference in the terms used for cold weather conditions. Frost, freeze and hard freeze all describe different circumstances.
- Frost is when water vapour freezes on surfaces. It usually happens on clear nights with still air and can happen when reported air temperatures are above freezing.
- Freezing is when cold air moves in and causes temperatures to drop below 32 degrees Fahrenheit. This condition commonly involves low humidity and wind, making drying out a big problem for plants.
- A hard freeze is when temperatures dip below 28 degrees Fahrenheit. Some tropical plants will survive a few degrees below freezing for very short periods, but extended periods of freezing or heavy frost may require lights or other heat used safely in combination with covering the plant.
Some plants can be moved indoors for the holidays and incorporated into the interior décor, rather than cramming them last-minute into a chaotic bundle when a freeze looms.
Get prepared by identifying old sheets, blankets and drop cloths which can be used as covers for tender or tropical zone plants which must remain outside. Test potential covers beforehand to assure all plants will be thoroughly covered.
It is best if the covers enclose the plant entirely without crushing it. Heavy blankets are great insulation, but only a good idea on the sturdiest of plants.
A tomato cage or other support structure can be used to keep the weight off the plant. Covers also need to be secured at the ground with pins or weights to assure cold air does not enter from below and collect under the cover.
Finally, keep storage bins handy and remove the covers in the daytime if temperatures are above 55 degrees Fahrenheit.
Monitor weather reports and react accordingly so tender and tropical plants see spring 2016.
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 | Jul 15, 2015
Native yuccas fit easily into the landscape without breaking the bank or the back of the gardener.
Being sharp is usually considered a complement. It implies the recipient of this assessment has the intellectual ability and the mental acuity to handle with ease the rigors of contemporary life.
In north Florida’s native plant world the yucca genus was sharp long before people employed it in landscapes. It also has the sharp pointy spines to enforce its tactics.
Local yuccas are perennial shrubs which can grow into small trees with a unique shape. There are approximately 50 species in this genus worldwide on every continent except Antarctica.
Their most obvious and notable feature which makes them easy to identify is their leaves. These are elongated in thick clusters around the stems.
The sword-like shape is tipped with a hardened point which can quickly get the attention of anyone passing too close. The bristly structure of these evergreen plants gives them an intimidating appearance which most animals and people avoid.
The annual blooms appear at the top of these plants and protrude above the greenery. Honeybees and other pollinators will visit the profusely fragrant bell-shaped flowers to collect nectar and pollen.
In their native range, these plants are seen in sites where there is high exposure to the sun. They will not grow in heavy shade, and languish with little change if there is less than six to eight hours of daily sun.
Sandy well drained soils are the most likely locations where yuccas will prosper and grow. Their nutrient requirement are low, so they rarely display symptoms of a nutrient deficiency.
Likewise, their need for water is paltry. Once established they will easily withstand droughts and extended dry periods.
The common species native to north Florida in this genus are Adam’s needles (Yucca filamentosa) and Spanish bayonets (Yucca aloifolia). These plants are similar in appearance, but each has distinctive traits.
Adam’s needles are the smaller and shorter of the two species. The multiple stems may reach three feet in height, but extend to over six feet when the cream color blooms appear in early summer.
The green leaves are pliable with white threads of fiber trailing from each. There is a variegated cultivar which is popular for landscaping projects.
Spanish bayonets produce multiple trunks per plant and may grow to over 15 feet. They produce rigid dark green leaves projecting from the thick trunks and will impale any trespasser.
White blossoms appear in the center of the plant above the foliage from spring to late summer depending on several weather related factors. These yuccas have a high salt tolerance making wild plantings common to coastal areas.
Disease and insect problems are few for these hardy plants. Too much water resulting in excessively wet roots and extreme cold are the biggest problems.
For the sharp homeowner these native plants make a pointedly good addition to the landscape.
To learn more about native yuccas in north Florida, contact the nearest UF/IFAS Extension office.
by Les Harrison | Jun 15, 2015
Eastern Blood-sucking Conenose bugs are found in and around plant where they are hunting for insects.
While it is not exactly a jungle “out there” in the landscape, there are some occasionally encountered insects which can inflict pain. The kissing bug and the blood-sucking conenose are native insects which are best not physically encountered.
The native kissing bug, Triatoma sanguisuga, is part of the assassin bug family. This insect is commonly called a kissing bug because it targets the soft tissues around the mouth of mammals as a feeding site.
As if being in the assassin bug family is not bad enough for its image, this pest’s South American cousin is responsible for inoculating victims with Chagas disease. Chagas disease, a protozoan infection, has occurred in some western states but not Florida.
The bloodsucking conenose, in assassin bug family too, is found in north Florida. It is a dark brown, winged bug, 3/4 inch long, with the edges of its abdomen alternating in light and dark colors.
They have a slender, straight beak with piercing-sucking mouthparts. The antennae are inserted on the side of the head between the eyes and the end of the beak.
They are rarely seen during the day, instead hiding in leaf litter and other debris near their intended host. Birds apparently consider them quite tasty and are easy targets for avian predators.
Kissing bugs primarily feed at night on the blood of sleeping animals, such as raccoons and opossums which burrow in the vicinity.
Their life cycle varies considerably depending on temperature, humidity, and availability of hosts. Females lay one egg at a time, up to five eggs each day.
Problems arise when these insects encounter humans. If this creature enters a home or dwelling, its nocturnal habits make humans easy prey.
The bloodsucking conenose will enter into a home by crawling through cracks in the foundation, torn window screens, or other structural flaws or inadequacies. Many times they enter by simply clinging to a domestic pet or to the clothing of an unaware person. Once indoors, they are found in bedding, cracks in the floors and walls, or under furniture.
Most bites from conenose bugs are rarely felt. However, some can be quite painful and infection can occur if the wound is scratched and contaminated.
The assassin bug, the entomological cousin of the kissing bug, usually is encountered in foliage and has little inclination to enter homes. It is capable of delivering a nasty surprise to the unsuspecting gardeners who disturb this ambush predator.
The green leaves and pretty flowers are an ideal habitat for the assassin bug and the kissing bug to put the bite on ideal menu selections. This is something to keep in mind this spring when enjoying the panhandle Florida’s great outdoors.
To learn more about the assassin bug or the kissing bug, contact your UF/IFAS Extension Office.
by Les Harrison | May 19, 2015
Uninvited guests can sometimes be fun and entertaining, bringing spontaneity to an otherwise predictable schedule. Sometimes the surprise guest is just an unpleasant distraction with no redeeming virtues.
The unanticipated knock on the door can bring both scenarios to mind. Almost everyone has an enjoyable cousin who regales listeners with amusing tales, and picks up the check for dinner.
Likewise, there are those potential callers with parasitic qualities, the appetite of a market hog, and initiative of a sloth. The Eastern Tent Caterpillar is one such visitor in north Florida.
These native caterpillars build large, thick nests on the branch forks and crotches of many kinds of trees, seeming to always choose the prized specimens highly valued by the homeowner. The silky tent shaped nests are easy to see and identity in host trees.
The caterpillars emerging in the spring of 2015 were laid in the spring of 2014. The adult moth lays her eggs in a single batch in May to July in the panhandle. There are 200 to 300 eggs laid in the group.
The mass of eggs are shiny, reddish-brown and look like dried foam. They are ordinarily about six inches back from the tip of a thin twig in host tree.
In approximately three weeks the eggs contain fully formed caterpillars, but the small caterpillars remain in the eggs until the following spring.
In late-February to mid-March they chew their way through their egg shells ready to eat their host tree that is entering the spring budding period with plentiful tender vegetation.
The voracious larvae immediately infest and, if in sufficient numbers, defoliate plum, cherry and many others. Normally the trees recover after a few weeks, but weakened or diseased trees may die.
When not eating, the newly hatched caterpillars construct their silk tent. The caterpillars use a pheromone trail to guild them back home when foraging is done.
A social insect, the eastern tent caterpillars congregate at their specific tent during the night and in rainy weather, expanding it to accommodate their growing size. These caterpillars do not feed within their nests.
The caterpillars disperse to colonize new areas when maturity is reached. They construct cocoons in protected places once they have sufficiently scattered.
Birds are not attracted to these hairy caterpillars. If they have a heavy concentration of black cherry leaves in their diet, the caterpillars will have a bitter acrid taste.
Parasitic wasps and weather are the two most common causes of caterpillar death. These caterpillars are especially susceptible to cold weather once they have emerged from their eggs.
About two weeks later, an adult moth emerges to begin the process again. Mating and egg laying commonly occur within 24 hours of the moths emerging from their cocoons
These brown moths are nocturnal and are seen flying only at night. They are an inch to two inches wingtip to wingtip at maturity and easy to overlook.
Tent Caterpillars are quick to hatch and eat their way through home landscapes.
Unfortunately, once they arrive for a visit they always overstay their welcome.
Contact your local UF/IFAS County Extension Office to learn more about Eastern Tent Caterpillars in north Florida.
