Phosphorus – Know Your Soil

Phosphorus – Know Your Soil

In our area of Florida, soils will vary in the amount of nutrients they hold. In general, we think of our soils as nutrient poor because sand is often the highest component. Sandy soils have large pore spaces and the particles themselves do not ‘attract’ many of our nutrients. Therefore needed plant nutrients can leave a sandy soil quickly, especially when rainfall or irrigation is prevalent.

There are areas along the Panhandle that do have more quality soils that have the ability to retain some nutrients. Also, frequent fertilizer or lime applications in home landscapes can create soils with abundance of certain nutrients over time .

One nutrient that may become prevalent in routinely fertilized soils is phosphorus. We know that phosphorus is one of the big three nutrients needed by plants in order to grow and flourish. When we routinely apply phosphorus to garden beds or lawns, it can build up. Phosphorus is a nutrient that does not leave the soil as readily as other nutrients. It binds to other elements to hang around. If we keep adding phosphorus to the soil, even though there is plenty there, problems can occur. One negative impact is the potential for soils with phosphorus to wash away and pollute local water systems.

Phosphorus is absolutely necessary for plant growth. It is needed for the energy transfer which is involved in plant growth functions. Phosphorus is also important for flower and fruit formation, and root growth.

Flowering plants benefit from fertilizer but make sure your soil needs the nutrients before an application.  Photo:  Beth Bolles, UF IFAS Escambia Extension

Flowering plants benefit from fertilizer but make sure your soil needs the nutrients before an application. Photo: Beth Bolles, UF IFAS Escambia Extension

There can be too much of a good thing. The key to remember, as with any nutrient, is make sure it is needed before applying it to your soil. Plant growth will not be improved beyond what is normal by adding more of any nutrient. Before you grab the bloom promoter or starter fertilizer with high phosphorus, run a soil test to accurately determine what is really needed in your soil.

 

Alert: Ambrosia Beetles !

Alert: Ambrosia Beetles !

Frass (toothpick-like projections) extends from entry holes on a Jeruselum thorn damaged by cold temperatures.  Photo by Beth Bolles, UF IFAS Escambia Extension

Frass (toothpick-like projections) extends from entry holes on a Jeruselum thorn damaged by cold temperatures. Photo by Beth Bolles, UF IFAS Escambia Extension

Winter injury and stress to many trees has attracted granulate ambrosia beetles to landscapes. These beetles mostly prefer weakened trees and cut stumps/logs but have been found to attack some healthy trees as well.

Adult beetles are very small, only about 1/16 inch long and bore into branches and trunks of many woody plants. They will push out small ‘strings’ of boring dust which look like toothpicks. These strings successfully protect the beetles as they establish galleries for laying eggs and rearing young within the tree. The adult females will introduce a fungus (ambrosia) into these galleries on which both the young beetles and adults feed.

 

Ambrosia Beetle Entry Point. Photo by Matthew Orwat

Ambrosia Beetle Entry Point. Photo by Matthew Orwat

Many beetles will bore into a plant, mostly along the trunks. Plants may be ultimately killed, not by the beetles but by the fungi that interfere with the movement of fluids within the tree.

If you notice a tree infested with ambrosia beetles, it is best to remove the plant quickly. Remove all infested plant parts from your landscape. If you have a special plant that you want to save, you may be able to cut it back close to the ground, and allow it to resprout. It would be necessary to monitor the remaining portion carefully for reinfestation and treat with an approved insecticide to prevent beetle entry.

Interior of damaged stem.

Interior of damaged stem.

Rethinking the Eastern Mole

Rethinking the Eastern Mole

How can an animal that does such much to help rid your lawn of pests be so hated by most homeowners?  Such is the life of the mole.

The beneficial mammal is a soil dweller that tunnels through the soil, increasing aeration as it searches out a meal of  beetle grubs, mole crickets, and slugs.  Moles prefer loose soil and can tunnel more than 15 feet an hour.  Moist soil brings the food source closer to the surface which in turn bring moles up to expose raised tunnels to homeowners.  These tunnels are mostly cosmetic and show up easily in mulched areas and lawns with heavier weed populations.  Most homeowners with a healthy, thicker lawn will rarely notice mole activity unless they encounter loose areas as they walk over the turf.  These can easily be pressed back down with your foot.

Mole tunnel in weedy area.  Photo:  Beth Bolles, UF IFAS Extension Escambia County

Mole tunnel in weedy area. Photo: Beth Bolles, UF IFAS Extension Escambia County

There are management techniques for moles which include traps and ridding the lawn of the food source.  The best practices are to manage the turf through proper mowing, watering, and fertilizing to create a uniform, healthy cover.  For the most part, mole management is not even required.  Consider the benefits of the moles as predators and allow them to be a natural part of the landscape environment.  For more information on moles read the University of Florida IFAS Extension publication.

Pollinator Protection

Pollinator Protection

 

Landscapes will soon be transitioning from the dormant phase to actively growing and one of the most beneficial insects of all will be back in action.  As soon as flowers open, bees will be visiting to gather pollen and nectar.

This year be a little more observant in the landscape and at your local nursery so that you protect bees during your yard activities.  Several insecticides will have new labels that indicate a toxicity to bees and restrictions about applications to blooming plants.  Since many landscapes have a wide variety of blooming plants, be very careful not to inadvertently spray when bees are visiting open flowers.  Bees are not only killed by a direct spray of certain insecticides, but may carry residual pesticides back to the colony in pollen and nectar.

Since bees and other pollinators are so vital to our food production system, all people who work in landscapes or enjoy gardening as a hobby, need to be a part of bee protection.  Read labels, only spray when absolutely necessary, and learn that a little cosmetic damage is worth it in order to protect pollinators.

Some selections of hollies are one of the first landscape shrubs visited by bees in the winter. Learn about the other plants in your yard that are visited by bees so you are better able to protect them.

Holly flowers will soon open.   Photo:  Beth Bolles, UF IFAS Escambia County Extension

Holly flowers will soon open.
Photo: Beth Bolles, UF IFAS Escambia County Extension

Reliable Hollies

Reliable Hollies

Looking for a new shrub or small tree this year?  Interested in one that is low maintenance and offers beautiful green color?  Why not try a holly.

Hollies can be found in landscapes throughout North Florida.  Many times these plants are used in foundation plantings around homes.  They can help make the transition from the hard lines of a home to other parts of the yard.  In other landscapes, hollies make an excellent screen, dividing property or blocking a view.

Because hollies are commonplace, they may be overlooked by homeowners who want to add an attractive new plant to the landscape.  Hollies have many uses and there are new selections entering the market worth considering.

In general hollies will not need a great amount of maintenance.  Once established most species will require only occasional water, fertilizer, and pruning.  Many hollies have even grown well under neglected conditions.  If you are one that keeps holly plants pruned as hedges, you will need to watch for the scale insect and spray plants with a horticultural oil every year.

When selecting a holly plant, it is good to know a little about the area where you want to place the plant.  Hollies vary in size and ability to tolerate wet soil, so it is important to match a species with your specific site.  Also consider holly leaf shapes when using the plants in areas where people walk.  Some holly leaves are very stiff and sharp and could injury visitors to you home or be a nuisance when you are working in the yard.

If you are interested in the added beauty of holly berries during the year, remember to select a female plant.

Hollies also attract bees to the landscape. Credit: Beth Bolles, UF IFAS Extension Escambia County

Hollies also attract bees to the landscape.
Credit: Beth Bolles, UF IFAS Extension Escambia County

Tree form hollies that you may select include the American holly (Ilex opaca), Savannah holly (Ilex x attenuata ‘Savannah’), and the Burford holly (Ilex cornuta ‘Burfordii’). All three plants will need well-drained soil.  The American and Savannah holly will both reach heights between 20 and 40 feet and have a pyramidal growth form.  The Savannah holly leaves will be a lighter green color than the leaves of other holly species.  Burford holly has thick dark green leaves and grows about 12-15 feet in height over time.

Burford holly is a beautiful holly that gives birds a place to hide.   Credit:  Beth Bolles, UF IFAS Extension Escambia County

Burford holly is a beautiful holly that gives birds a place to hide.
Credit: Beth Bolles, UF IFAS Extension Escambia County

If you have a wet site, consider the Dahoon holly which can be a specimen plant or used as a screen. This plant will develop attractive grayish bark and grow about 20 feet in height with more of a spread than the previously mentioned hollies.

There are medium-sized hollies that make excellent specimen plants about 12 feet in height.  ‘Festive’ holly has dark green foliage and forms dense growth in a pyramidal form.  The ‘Robin’ holly has a similar growth form but displays beautiful reddish new growth.  Both of these plants will need well-drained soil and full sun or partial shade.

For those areas that require smaller evergreen plants, consider a Bordeaux’ yaupon holly.  These plants will grow about 4 feet in height and spread and  form a dense growth of stiff stems with small leathery leaves.  Since these plants keep a naturally round form it is not necessary to shear them.  Both hollies will tolerate a wide range of soil conditions and require little maintenance once established.