Winter Shrubs

Winter Shrubs

Photo Caption: Unused tomato cages are a perfect support for heavy covers which can protect delicate landscape shrubs during the frosts of winter. When spring arrives, they can again be used to support tomato plants. Image Credit Les Harrison

The Thanksgiving turkey is but a distant memory, the stores are stocking for the spring, and Christmas decorations are coming down.

The advent of the new year, finally brings the inevitability of cold and frosty weather. While nothing complements a nice eggnog or hot chocolate like a chill in the air, some northwest Florida landscape plants do not appreciate the dropping temperatures.

Gardeners face 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.

Many homeowners and landscape managers want to know when plants will need protection. Depending on the plant, the point of freezing is a good rule of thumb. Freezes  will likely occur this season so preparations should begin now.

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.

In the Panhandle, most of the risk for sustaining freeze damage happens during the busy holiday season. People are busy, schedules are disrupted and the distractions, pleasant thought they be, may cause homeowners to miss a critical freeze alert in the media.

Some plants can be moved indoors for the cold months and incorporated into the interior décor, rather than cramming them last-minute into a chaotic bundle when a freeze looms.

While putting away the holiday decorations into storage, identify old sheets, blankets and drop cloths which can be used as covers for tender 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 your tender and tropical plants see spring 2018. Santa will approve.

When is the Correct Time to Harvest Satsumas?

When is the Correct Time to Harvest Satsumas?

Fall 2016 Satsumas. Image Credit: Matthew Orwat

    Fall 2016 Satsumas. Image Credit: Matthew Orwat

One question that repeatedly pops up in my Extension work is “When do I harvest fruit or vegetable X ?”  This fall, the question of “when should I harvest my citrus?” has been a choice topic! The most common citrus in the Florida panhandle is the satsuma, Citrus unshiu, so it makes sense to limit this article to that species.

Harvesting satsumas can be a confusing activity for new citrus enthusiasts. Fall seasons in the panhandle tend to be extremely variable, from cold and wet to warm and dry or any combination thereof. To complicate matters, citrus is often grown in a protected microclimate in the garden. Thus, another variable is added to the decision tree.

Some harvest considerations to take note of:

  • Sometimes the fruit is ready to harvest even when some green remains on the fruit
  • Not all fruit on a given tree will be ready at the same time
  • It’s a good idea to harvest a few fruit per tree and taste test….this will be a good indicator of the readiness of the other fruit on the tree
  • A general trend to consider is that the longer the fruit remains on the tree, the sweeter it will become
Image Credit Matthew Orwat

Image Credit Matthew Orwat

When satsuma ripen, they become slightly soft. That’s a good indicator that they are ready to harvest. This softness makes them extremely easy to peel but poses a challenge when harvesting. If they are simply pulled off of the tree, some peel will be left on the tree and the fruit will be compromised. Such a fruit would have to be consumed quickly. To solve this problem satsuma are clipped off the tree, leaving a tiny bit of stem attached to the fruit. This allows the fruit to be stored and transported.

When a hard freeze is approaching (5 hours below 28ºF), it is important to harvest the fruit before this event whether or not they are ripe. Hard freezes will ruin the texture of the fruit and cause them to begin the rotting process.

Since a hard freeze is forecast for Friday December 9th 2016 for part of the Florida Panhandle, consult your local weather forecast and make your decisions accordingly.  For an in-depth discussion on citrus fruit harvesting and cold tolerances, please consult this publication from Texas A& M University. Additional articles are available on cold protection and frost readiness here.

 

Palms Can Suffer in the Cold

Palms Can Suffer in the Cold

Medjool Palm LandscapeWhile palms may survive, or even thrive, for years in climates cooler than those to which they are native, eventually they will experience temperatures cold enough to cause injury. Here in Northwest Florida, it was January 2014.  Unfortunately, much of the damage was not evident until the summer of 2015.  The palms held on with stored food reserves.

When cold damage is severe, plant tissues are destroyed and water uptake into the plant may be reduced for years. Many times it is only the protected bud that will remain alive.  The stem slowly weakens until it can’t support the weight of the crown and it collapses.palm collapse

Winter is upon us again. So, if you still have palms in the landscape, be prepared, should we experience some extreme weather.  Here’s a reminder of what to do.

One of the most common problems associated with freezes is that the freeze-killed lower portion of the spear leaf is degraded by secondary fungi and bacteria that are always present in our natural environment. Palm owners are often anxious to trim off the damaged leaves following a cold weather event.  Avoid the temptation to remove these fronds until danger of additional freezes has passed.  Even dead leaves provide insulation to the critical bud.

As the weather warms, the dead fronds need to be removed from around the bud so that the spear can begin to dry out. Drenching the bud area with a copper fungicide will reduce the secondary microbes.  Repeat applications will need to continue as the palm leaves develop.  Copper fungicides, unlike other fungicides, are active against bacteria and fungi.  Be cautious to not use a copper nutrient spray rather than a fungicide.  Delay fertilizer application until new fronds have developed.  The best analysis for palms is 8-2-12 + 4Mg.  Utilization of proper palm fertilization can improve cold hardiness of palms.

Palms damaged by cold can still show symptoms six months to a year following a freeze. New leaves in the spring may appear mis-shaped.  Usually the palm will outgrow the damage.  However, sometimes the palm loses its ability to take up water.  If there is a sudden collapse of the fronds in the crown during the first hot days, the palm may die.  There is nothing that can be done to save the palm.

 

Prepare Now to Protect Delicate Shrubs and Tropical Plants

Prepare Now to Protect Delicate Shrubs and Tropical Plants

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.

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.

Gardener’s To Do List for December

Gardener’s To Do List for December

growing-daffodilstree pruningThough the calendar says December, the weather in Northwest Florida fluctuates between winter and spring temperatures. The nice days are wonderful opportunities to accomplish many of those outside landscape chores in preparation for spring.  But, it is also a good time to start planning for next month’s colder temperatures.  Since we don’t experience frozen soil, winter is the best time to transplant hardy trees and shrubs.  Deciduous trees establish root systems more quickly while dormant; versus installing them in the spring with all their tender new leaves.  Here are a few suggestions for tasks that can be performed this month:

  • Plant shade trees, fruit trees, and evergreen shrubs.
  • Plant pre-chilled daffodil and narcissus bulbs (late December/early January).
  • Do major re-shaping of shade trees, if needed, during the winter dormancy.
  • Water live Christmas trees as needed and water holiday plants such as poinsettias as needed.
  • Check houseplants for insect pests such as scale, mealy bugs, fungus gnats, whitefly and spider mites.
  • Continue to mulch leaves from the lawn. Shred excess leaves and add to planting beds or compost pile.
  • Replenish finished compost and mulch in planting beds, preferably before the first freeze.
  • Switch sprinkler systems to ‘Manual’ mode for the balance of winter.
  • Water thoroughly before a hard freeze to reduce plants’ chances of damage.
  • Water lawn and all other plants once every three weeks or so, if supplemental rainfall is less than one inch in a three week period.
  • Fertilize pansies and other winter annuals as needed.
  • Protect tender plants from hard freezes.
  • Be sure to clean, sharpen and repair all your garden and lawn tools. Now is also the best time to clean and have your power mower, edger and trimmer serviced.
  • Be sure the mower blade is sharpened and balanced as well.
  • Provide food and water to the area’s wintering birds.Spreading-Mulch