Don’t Water When it’s Already Wet

Don’t Water When it’s Already Wet

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 spray head running
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

Selecting Wind-Resistant Trees for Hurricane Season

Selecting Wind-Resistant Trees for Hurricane Season

The Pensacola area has had its fair share of rough weather lately. While the recent storms were not hurricanes, the rainfall totals rivaled many tropical storms, and the lighting and wind were disastrous. A tornado caused significant damage, including a tragic death, with more tumultuous weather in the forecast. Our rainy hurricane season has just begun, so it is worth talking about tree selection, management, and preparing for storms.

After the busy 1992, 1995, 1998, and 2004-05 hurricane seasons, several University of Florida researchers undertook an exhaustive on-the-ground project to look at tree damage statewide. Their goal was to determine which species survived high winds, and which trees were the most vulnerable during storms. Their findings were consistent, and have held up over the past few decades. A full description of the project can be found online, along with several publications that go over proper pruning and maintenance of trees, both before a storm and after recovery.

Live oaks have dense wood and are extremely wind-resistant species. Photo credit: Carrie Stevenson, UF IFAS Extension

For the “coastal plain” of north Florida, the most wind-resistant species are: live and sand live oaks (Quercus virginiana/Q. geminata), American holly (Ilex opaca), Sabal palm (Sabal palmetto), Southern magnolia (Magnolia grandiflora), bald cypress (Taxodium distichum), Florida scrub hickory (Carya floridana), dogwood (Cornus florida), sweet gum (Liquidambar styraciflua), and crape myrtle (Lagerstroemia indica). The live oaks and sweet gums do have a tendency to lose branches, so it is important to undertake proper pruning in the off season to trim up potential problem limbs.

This chart developed by UF researchers denotes the percentage of trees surviving Hurricane Ivan, by species.
Courtesy M. Duryea and E. Kampf

Live oaks, and sand live oaks (which live on coastal sand dunes) are slow-growing trees with extraordinarily dense wood. This protects them in hurricane-force winds. Part of the working theory on why bald cypress, holly, and magnolia do well in storms is their pyramidal shape, which seems to allow wind to whip circularly around the trees and avoid damage. Sabal palms are botanically considered part of the grass category and not trees, so their single, flexible trunk allows them to handle the onslaught of wind. Sweetgums are particularly hardy in tornadoes, due to their sturdy root system and shorter, “stout” branches. Smaller understory trees like crape myrtle and dogwood are likely dodging the strongest winds, but also have strong branch structures and dense wood. These two species, along with sand live oak, also lost an average of more than 80% of their leaves. This defoliation is an adaptation to heavy winds, with trees that lost leaves performing better overall than species that held onto their leaves but toppled at the trunk.

The least wind resistant species, according to the studies, included: sand pine (Pinus clausa), loblolly pine (Pinus taeda), and spruce pines (Pinus glabra)laurel and water oaks (Quercus laurifolia/Q. nigra), Southern red oak (Quercus falcata), Southern red cedar  (Juniperus silicicola), Carolina laurelcherry (Prunus caroliniana), black cherry (Prunus serotina), Loquat (Eriobotrya japonica), pecan (Carya illinoensis), sycamore (Platanus occidentalis), tulip poplar (Liriodendron tulipifera), Bradford pear (Pyrus calleryana), and red maple (Acer rubrum). A couple of pine species—slash and longleaf—performed in the medium range. In my experience post-hurricane, many of these trees that survived were stressed and ended up with pine bark beetle infestations. Water and laurel oak are common trees in Florida home landscapes, but typically have much shorter lifespans than live oaks. They are faster growing but have weaker wood, and are vulnerable to storms.

Significant damage to a home after a tornado struck Pensacola in 2016. Photo credit: Carrie Stevenson, UF IFAS Extension

Another list of tree survivability was developed for residents in tropical and subtropical regions of the state. If you have friends or family in south-central Florida, be sure to share this information with them.

Besides planting wind-resistant species, the research team shared other observations related to tree planting and arrangement, too. Single trees are more vulnerable than trees planted in clusters, as they protect each other from incoming winds. Older trees, and those with preexisting damage, are more likely to fall. Trees with plenty of space around their roots do better—if a tree is surrounded on two or more sides with buildings or other hard surfaces, they cannot spread adequately. Detailed information on identifying damaged or poorly structured trees, along with maintenance and pruning tips, can be found in the “Urban Forest Hurricane Recovery Program” series of articles written by the UF tree specialists involved in the studies. The publications include good diagrams and photos of specific examples.

Rainlily: A Rewarding Bulb for Panhandle Gardeners

Rainlily: A Rewarding Bulb for Panhandle Gardeners

Bulbs are my favorite class of ornamental plants.  They generally are low maintenance, come back reliably year after year, and sport the showiest flowers around.  While many bulbs like Daylily, Crinum and Amaryllis are very common in Panhandle landscapes, there is a lesser-known genus of bulbs that is well worth your time and garden space, the Rainlily (Zephyranthes spp.).

Rainlily, aptly named for its habit of blooming shortly after summer rainfall events and a member of the Amaryllis family of bulbs, is a perfect little plant for Panhandle yards for several reasons.  The plant’s genus name, Zephyranthes – which translates to English as “flowers of the western winds”, hints at the beauty awaiting those who plant this lovely little bulb.  From late spring until the frosts of fall, Rainlily rewards gardeners with flushes of trumpet-shaped flowers in shades of white, pink, and yellow, with some hybrids offering even more exotic colors.  While these individual flowers typically only persist for a day or two, they are produced in “flushes” that last several days, extending the show.  Though Rainlily flowers are the main event for the genus, beneath the blooms, plants also offer attractive, grass-like, evergreen foliage.  These aesthetic attributes lend themselves to Rainlily being used in a variety of ways in landscapes, from massing for summer color ala Daylilies, to use around the edges of beds as a showy border like Liriope or other “border” type grassy plants.

Unknown Rainlily species blooming in a raised bed. Photo courtesy of Daniel Leonard.

Continuing along the list of Rainlily attributes, the genus doesn’t require much in the way of care from gardeners either.  Most species of Rainlily, including the Florida native Z. atamasca, have no serious pests and are right at home in full sun to part shade.  Once established, plants are exceedingly low-maintenance and won’t require any supplemental irrigation or fertilizer!  Some Rainlily species like Z. candida even make excellent water or ditch garden plants, preferring to have their feet wet most of the year – putting them right at home in the Panhandle this year.  And finally, all Zephyranthes spp. do very well in containers and raised beds also, adding versatility to their use in your landscape!

The one drawback of Rainlily is that they can be somewhat difficult to find for sale.  As these bulbs are an uncommon sight in most garden centers, to source a specific Zephyranthes species or cultivar, one is probably going to need to purchase from a specialty internet or mail-order nursery.  As with other passalong-type bulbs though, the absolute best and most rewarding way to obtain Rainlily is to get a dormant season bulb division from a friend or fellow gardener who grows them.  There are many excellent unnamed or forgotten Zephyranthes cultivars and seedlings flourishing in gardens across the South, waiting to be passed around to the next generation of folks who will appreciate them!

Even if you must go to some lengths to get a Rainlily in your garden, I highly recommend doing so!  You’ll be rewarded with years of low-maintenance summer color after the dreariest of rainy days and will be able to pass these “flowers of the western wind” on to the next gardening generation.  For more information on growing, sourcing, or propagating Rainlilies, check out this EDIS publication by Dr. Gary Knox of the UF/IFAS North Florida Research and Education Center (NFREC) or contact your local UF/IFAS Extension office!  Happy Gardening!

 

 

 

It’s Green, Gelatinous and in My Lawn

It’s Green, Gelatinous and in My Lawn

The lawn is a source of pride for most and anything out of the ordinary causes alarm.  Now image finding something that looks like lumpy green jelly in your turfgrass and it doesn’t go away.  You try raking it, spraying it, covering it, and it still comes back time and time again.  One of the things we see in late spring/early summer turf is a reemergence of cyanobacteria (Nostoc), sometimes confused with algae because of green coloring and this remains all summer long.

Dehydrated cyanobacteria in a centipedegrass lawn.

Unlike normal bacteria that needs a food source, cyanobacteria contains chlorophyll and produces its own food source through photosynthesis which allows it to grow on bare sandy soils, fabric mats, concrete sidewalks, plastic, and yes even your lawn.  Besides the green pigment, it also produces a blue pigment and is why we call it cyanobacteria which means blue-green bacteria.  In addition to photosynthesis, cyanobacteria can also fix nitrogen, and are believed to produce cyanotoxins and allelopathic compounds which can affect plant growth around them.

Cyanobacteria are considered one of earth’s oldest organism and they have tremendous survival capabilities. They can dry out completely, be flat, flaky, black-green dried particles in your lawn and once rehydrated, spring back to life.  If you happen to notice it spreading throughout your yard, remember that pieces of the organism can stick to your wet shoes or lawnmower tires and be transported unintentionally.

The question then becomes how to control the cyanobacteria and reclaim your turfgrass.  The first solution is to have a healthy lawn.  Cyanobacteria likes poorly-drained compacted soils.  This same condition is unfavorable to turf growth and why you end up with bare spots and establishment.  Reduce soil compaction by using a core aerator, and then adding organic matter.  This will increase drainage, gas exchange, and encourage microorganism populations which I like to call soil pets.  Spike aerators only push the soil particles aside and don’t really loosen as well.  Try to reduce low lying areas in the lawn where water sits after rainfall and irrigation.  You might have to till and reestablish those areas of the yard.

Hydrated cyanobacteria

The same cyanobacteria pictured above 24 hours after being rehydrated in a petri dish of standing water.

Controlling the amount of water Mother Nature gives us and humidity levels during summer is not possible, but you can control your irrigation whether it be automatic (sprinkler system) or hand-watered.  During the rainy season, you should be able to get by with only rainfall and shut off your system.  If needed during extended dry weeks, it is easy enough to turn the system back on.  It is thought that cyanobacteria likes phosphorus which is another reason to use little to no phosphorus in your lawn fertilizers.

As you begin to rid your lawn of cyanobacteria, remember when fully hydrated it forms a slippery surface so be careful walking on it.  Cultural practices will be more effective in controlling the spread versus using chemical methods.  Cultural solutions are safer for your lawn, yard and all of the wildlife that visits.  If you need help with your cyanobacteria, please contact your local Extension office and we are always happy to assist.

A special thanks to Dr. Bryan Unruh, UF/IFAS for his assistance in identifying the cyanobacteria.

For additional information, please read the sources listed below.

 

 

 

 

Biology and Management of Nostoc (Cyanobacteria) in Nurseries and Greenhouses.  H. Dail Laughinghouse IV, David E. Berthold, Chris Marble, and Debalina Saha

Rain, Overwatering Can Cause Slippery Algae to Pop Up in Turfgrass.  C. Waltz

Nostoc.  N.J. Franklin

 

 

 

Five Reasons for Lack of Fruiting in Figs

Five Reasons for Lack of Fruiting in Figs

Q. One of my two fig trees has produced a few figs. The other one, which is the largest and healthiest tree, has never had a fig on it. Both where planted six years ago. Why is it not producing?

Section of mature fig tree with ripe fruit

Mature fig tree with fruit. Photo credit: Larry Williams

A. It may be a matter of age and being overly vigorous. When a fruit tree is younger, it puts most of its energy into producing leaves and shoots. Until the plant becomes mature and slows down in the production of leaves and shoots, it will produce few to no fruit. It may take a year or two more for your tree to slowly and gradually switch from producing mostly leaves and shoots to producing and maturing some fruit. Patience is needed.

Be careful to not overdo it in fertilizing and/or pruning your fig tree. Too much fertilizer, especially nitrogen, or severely pruning the tree will result in the tree becoming overly vigorous at the expense of setting and maturing fruit. This includes fertilizer that the tree may pull up from a nearby lawn area. A tree’s roots will grow outward two to three times beyond its branch spread into adjacent lawn areas.

The end result of being heavy handed with fertilizing and/or overdoing it in pruning is the same – it forces the plant to become overly vigorous in producing leaves and shoots at the expense of producing and maturing fruit.

In addition, the following is taken from an Extension publication on figs and includes the most common reasons for lack of fruiting, in order of importance.

  1. Young, vigorous plants and over-fertilized plants will often produce fruit that drops off before maturing. If plants are excessively vigorous, stop fertilizing them. Quite often, three of four years may pass before the plant matures a crop because figs have a long juvenile period before producing edible quality fruit.
  2. Dry, hot periods that occur before ripening can cause poor fruit quality. If this is the case, mulching and supplemental watering during dry spells will reduce the problem.
  3. The variety Celeste will often drop fruit prematurely in hot weather regardless of the quality of plant care. However, it is still a good variety to grow.
  4. An infestation of root-knot nematodes can intensify the problem when conditions are as described in item 2.
  5. You could have a fig tree that requires cross-pollination by a special wasp. This is a rare problem. If this is the case, then it will never set a good crop. The best way to resolve this is to replace the plant with a rooted shoot of a neighbor’s plant you know produces a good crop each year.
Cuban Treefrogs in the Panhandle

Cuban Treefrogs in the Panhandle

Photo by Dr. Steve Johnson

Treefrog calls are often heard with each rain event.  But, how about a “snoring raspy” call that begins after a day time light rain?  That may be a male Cuban treefrog trying to attract the girls.  Cuban treefrogs breed predominately in the spring and summer.  Reproduction is largely stimulated by rainfall, especially warm summer rains such as those associated with tropical weather systems and intense thunderstorms.

Range of Cuban treefrogs

The Cuban treefrog, Osteopilus septentrionalis, was accidently introduced to Florida in the 1920’s as a stowaway in shipping crates from the Caribbean.  Over the last hundred years, the invasive frog has managed to spread throughout Florida and the Southeastern U.S. by hitchhiking on ornamental plants, motorized vehicles, and boats.  Though occasional cold winters have created temporary population setbacks, new generations of Cuban treefrogs continue to be reported in north Florida, including the Panhandle.

An invasive species is generally defined as a plant, animal or microbe that is found outside of its native range, where it negatively impacts the ecology, economy or quality of human life. Cuban treefrogs come out at night to feed on snails, millipedes, spiders and a vast array of insects.  But, they are also predators of several Florida native frogs, lizards and snakes.  Tadpoles of the invasive Cuban treefrog have been shown to inhibit the growth and development of native Southern toad and green treefrog tadpoles when all of the species are in the same water body.  Additionally, a large female Cuban treefrog can lay over 10,000 eggs per season in very small amounts of water.

Panhandle citizens can help manage the invasive Cuban treefrog by learning to identify them and reduce their numbers.  All treefrogs have expanded pads on the ends of their toes.  Cuban treefrogs have exceptionally large toepads.  They also have a “big eyed” appearance due to their oversized bulging eyes.  Cuban treefrogs may exceed 6 inches in length, have warty-looking skin with possible blotches, bands or stripes, and vary greatly in color.  However, they can be distinguished from other treefrogs.  Cuban treefrogs have a yellowish wash where their front and rear legs are attached to their body.  Juvenile Cuban treefrogs have red eyes and blue bones visible through the skin of their hind legs.  The skin of the Cuban treefrog produces a sticky secretion that can cause a burning or itching sensation if it contacts the eyes or nose of certain individuals.  It is recommended to wear gloves and wash your hands after handling Cuban treefrogs.

It is important to document the locations of Cuban treefrogs in the Panhandle.  By placing short sections of PVC pipe in the ground around your home and garden will provide hiding places for treefrogs that enables you to monitor for Cuban treefrogs.  Cut 10 foot sections of 1.5-inch-diameter PVC pipe into approximately three-foot-long sections and push them into the ground about 3-4 inches.  To remove a frog from a pipe, place a clear sandwich bag over the top end, pull the pipe from the ground, and insert a dowel rod in the other end to scare the frog into the baggie.  If you suspect you have seen one, take a picture and send it to Dr. Steve Johnson at tadpole@ufl.edu.  Include your name, date, and location.  Dr. Johnson can verify the identity.  If it is a Cuban treefrog, upload the information by going to http://www.eddmaps.org/ and click the “Report Sightings” tab.

Once identified as a Cuban treefrog, it should be euthanized humanly.  To do that, the Cuban treefrog in a plastic sandwich bag can be placed into the refrigerator for 3-4 hours then transferred to the freezer for an additional 24 hours.  Alternatively, a 1-inch stripe benzocaine-containing ointment (like Orajel) to the frog’s back to chemically anesthetize it before placing it into a freezer.  After freezing, remove the bagged frog from the freezer and dispose of in the trash.  Ornamental ponds should also be monitored for Cuban treefrog egg masses especially after a heavy rain.  The morning after a rain, use a small-mesh aquarium net to scoop out masses of eggs floating on the surface of the pond and simply discard them on the ground to dry out.  Various objects that can collect water found throughout your yard need to be dumped out regularly to reduce breeding spots for both Cuban treefrogs and mosquitoes.