Tuesday, November 29, 2016

Yellow stars twinkle in the backyard garden


Some fruits are either feast or famine and the star fruit is one of those wonders.  This fall, not only was our starfruit at the East Port Environmental Campus Demonstration Garden producing, several Master Gardeners were also bringing in bags of extra fruit to share – nice!  Whether you call it carambola, star fruit or five-finger, the fruit tree known scientifically as Averrhoa carambola is exotic, tasty, and makes a nice ornamental yard tree. Why not try this tree fruit in your own back yard?

First, let me quote word for word from our UF/IFAS publication, "People who have been diagnosed with kidney disease should not eat carambola (star fruit) unless their doctor says it is safe for them to eat. This fruit may contain enough oxalic acid to cause a rapid decline in renal function." Please keep this important warning in mind.   Originally from Southeast Asia, the carambola has been grown in Florida for over one hundred years and is commercially produced in Dade, Lee, Broward, and Palm Beach counties. This fruit is commonly seen in produce departments in most grocery stores and is familiar to almost everyone. The carambola tree is small to medium in size, evergreen to semi-evergreen depending on winter temperatures and may have a single or multiple trunks. The small, but colorful pink to lavender flowers are about three-eighths of an inch long. The flowers are followed by a fleshy waxy berry from two to six-inches long with five lobbed ribs that appear star-shaped when cut in cross-section. It takes about seventy-five days from the time the fruit sets until it is ready to pick. There are also about twelve edible seeds per fruit. Carambolas really appreciate being protected from windy sites. As a matter of fact, wind damaged trees will show browning or distorted leaves, some stem dieback, fruit damage and general stunted growth. Keeping carambola trees pruned to about twelve feet tall will also help increase hurricane resistance. Select a site to plant your carambola that is in full sun, out of the wind and is well drained. If necessary, plant the tree on a mound of soil to raise it up above areas that sometimes flood. Build the mound three to four foot high and four to ten feet wide using native soil. Carambolas are not tolerant of salty conditions and also may show nutrient deficiencies in high pH soils. As the tree matures, it tolerance to cold and freezing will improve. Generally, at temperatures of twenty to twenty-four degrees Fahrenheit, large branches and even mature trees may die. Accordingly, some protection may be necessary during the coldest of our winter weather.

Carambola normally have two major crops per year ready from August through September and from December through February. There will also be scattered smaller crops. A five year old tree can produce up to one hundred pounds per tree. Mature trees can eventually supply you with over two-hundred and fifty pounds a year. It is no wonder why carambola tree owners are always giving fruit away to friends and neighbors! A complete fertilizer suitable for tropical fruits used as per label directions will keep the tree productive and healthy. In addition, foliar applications of micronutrients may be needed to ward off deficiencies. Variety selection is as much an issue of what is available in the local garden centers, and what your personal tastes are. Carambolas are either sweet or tart - some tart varieties will even sweeten up if left on the tree to ripen further. ‘Arkin’ is a cultivar that originated in Florida, has a sweet flavor and is very well suited for backyard production. ‘Lara’ is another variety from Florida that is also sometimes available. ‘Fwang Tung’ is also recommended.   Local box store garden centers and specialty nurseries regularly carry carambola.  Carambola is a great dooryard fruit tree that is easy to grow and produces an abundance of tasty fruit.  Perhaps give one as a gift to someone this Holiday Season! For more information on all types of fruit to grow in our area, please call our Master Gardener volunteers on the Plant Lifeline on Mondays, Wednesdays and Fridays from 1 to 4 pm at 764-4340 for gardening help and insight into their role as an Extension volunteer.  Don't forget to visit our other County Plant Clinics in the area.  Please check this link for a complete list of site locations, dates and times - http://charlotte.ifas.ufl.edu/horticulture/Plant%20Clinics%20Schedule.pdf.   

Resource: Crane, J. H. (2013) Carambola Growing in the Florida Home Landscape. The University of Florida Extension Service, IFAS.

Tuesday, November 22, 2016

Cousin of the lychee, the longan


The longan tree in our East Port Environmental Campus Demonstration Garden produced a good crop of fruit this year.  It is one of the few fruit trees producing fruit in August, so the small brown fruit were a welcome seasonal taste treat.  A family member of the lychee, the longan tree is an attractive evergreen all by itself – the fruit is just an added bonus!  Best grown in the warmer parts of Charlotte County or in noted microclimates, the longan may be something to try.

Originating in Southeast Asia, the longan reached our country in 1903 and has been a commercial crop in south Florida since the 1990’s. It is well adapted to the subtropics where there is a period of cool, but not freezing winters, and dry periods in the fall and winter.   Because of weather conditions, longan trees may not bear fruit every year.  In a good year, a mature tree can produce over fifty pounds of fruit.  The twelve-inch long evergreen leaves are shiny and dark green in color.  The flowers are small and arranged in what are called panicles.  The clusters of fruit that develop are round to oval and around an inch in diameter.  A brown leathery covering surrounds the white pulp which surrounds a dark brown seed.  The pulp is sweet and has a unique flavor.  Keep in mind that it takes, from flower to fruit, over one-hundred and forty days. 

Once established in a full sun site, the longan is very drought tolerant, but does not take flooding well.  The longan also does not like salty conditions which will cause leaf burn and general dieback.  As mentioned, the longan can take our subtropical climate for the most part, but can be damaged or killed when temperatures approach twenty-seven degrees F.  Growing unpruned upwards to thirty-feet tall, it should be trained to maintain a height of about fifteen feet tall.  Also consider fruit thinning.  By reducing about fifty percent of the fruit set when they are about one-quarter of an inch in the spring, each remaining fruit will be significantly bigger and more appealing.  This will help individual fruit approach the desired one and one-quarter of an inch (or bigger) diameter size which will have the most flesh and the best flavor.  Test a few fruits for taste before you harvest the entire cluster.  Longan fruit can be stored in a plastic bag in a refrigerator for up to seven days.

A number of box store garden centers regularly carry longan trees for sale.  In Florida, the number one cultivar planted is ‘Kohala’.  This has been found to be the best variety and is recommended for backyard plantings.  The biggest pest likely encountered will be birds eating the ripe fruit.  Bird netting works well to exclude the birds and protect the crop.

If you are looking for a non-citrus fruit tree to try, the longan might be a good choice for you.  Try the fruit ahead of time by visiting Pine Island tropical fruit growers in August to sample some of these tasty morsels!  For more information on all types of fruit to grow in our area, please call our Master Gardener volunteers on the Plant Lifeline on Mondays, Wednesdays and Fridays from 1 to 4 pm at 764-4340 for gardening help and insight into their role as an Extension volunteer.  Don't forget to visit our other County Plant Clinics in the area.  Please check this link for a complete list of site locations, dates and times - http://charlotte.ifas.ufl.edu/horticulture/Plant%20Clinics%20Schedule.pdf.   

Resource:  Crane, J. H., Balerdi, C. F., Sargent, S. A. & Maguire, I. (2013) Longan Growing in the Florida Home Landscape.  The University of Florida Extension Service, IFAS.  

Thursday, November 10, 2016

The palmetto weevil blues


“Oh no!” – was I all I could say as I noted the telltale brown fronds and slightly tilted, leaking canopy.  Our prized Bismarck palm was marked for death as masses of unseen three-inch long palmetto weevil larvae tunneled inside eating the heart out of this majestic palm.   Growing up to fifty feet tall, the stunning palm known as the Bismarck palm has become a popular landscape subject throughout Southwest Florida.  Planted as an accent specimen in many landscapes, beautiful silver-blue Bismarck palms tower over other plantings to the pride of homeowners.  Is this a good choice for your landscape? 

Originally from the island nation of Madagascar, Bismarckia nobilis have been popular landscape subjects in Southwest Florida for some time.  Potentially growing to an enormous size of up to sixty feet tall and twenty-feet wide, the Bismarck palm is widely sold in local garden centers and nurseries. The growth seen in these palms is fairly rapid and the one planted at our East Port Environmental Campus Demonstration Garden in Port Charlotte grew from a five-gallon, three foot plant to well over twenty-feet in about six years.  Site selection is very important and you should definitely “plan before you plant”.   Keep in mind that this palm often outgrows small residential lots as its gigantic proportions make everything around it look puny.  Bismarck palms are best planted in full sun on well-drained soil.  Once established, they are highly drought- tolerant and moderately salt-tolerant – good characteristics for our area.  A recommended fertilizer program for all palms includes the use of a granular 8-2-12-4 (or 8-0-12-4) in November, February and May, and a 0-0-16-6 in August, applied as per label directions.

Bismarck palms are best suited to Hardiness Zones 10A and 11.  Charlotte County has some zone 10A right along the coast, but further inland the zone changes to 9B – a potentially cooler area.  However, the Bismarck palm has been planted well out of its hardiness zone range all the way north to Orlando.  While there may be some micro-climates in these cooler areas, there is the real risk of freeze damage.  Some Bismarck palms in Charlotte County visibly suffered from freezes several years ago.  Months after these events, the Extension Office began to receive calls from heart-broken clients with failing Bismarck palms.  While some were associated with lightning strikes, many seemed to show evidence of stress due to cold damage to the bud.  This damage then led to palmetto weevil invasion and eventual collapse of Bismarck specimens in the landscape.  While we have not had a severely cold winter in a few years, Bismarck palms are still randomly dying from time to time.   Unfortunately, recent observations have indicated that even “apparently healthy” Bismarck palms may be attacked by palmetto weevils.  This was the case with our specimen.  Palmetto weevils are large beetles which are normally attracted to palms under stress.  Stressed palms give off a chemical scent picked up by passing palmetto weevils.  Once they find a suitable host, the weevils release chemicals that attract more weevils to the feast, and an infestation is born. 



It is still considered a good management practice to keep your palms healthy and stress-free (no over-pruning for example) – this should keep palmetto weevils at bay in most cases.   One band-aide approach may include a chemical option.  A root drench with Imidacloprid (a systemic insecticide) as per label directions may afford some degree of limited protection, but there are no guarantees. 

The funeral for our Bismarck palm has come and gone.  We enjoyed it as a crown jewel in our Demonstration Garden for years, but knew that we could lose it someday.  So, if you decide to plant a Bismarck in your landscape, check your hardiness zone or micro-climate options, consider the ultimate height and width of this behemoth, fertilize it properly and keep in mind that there are some factors out of your control that could limit this palm’s long-term success.  Those who already have Bismarck palms established in the landscape, keep them stress free, keep your options open on palmetto weevil deterrents, and appreciate these big blue giants!  For more information on all types of palms, please call our Master Gardener volunteers on the Plant Lifeline on Mondays, Wednesdays and Fridays from 1 to 4 pm at 764-4340 for gardening help and insight into their role as an Extension volunteer.  Don't forget to visit our other County Plant Clinics in the area.  Please check this link for a complete list of site locations, dates and times - http://charlotte.ifas.ufl.edu/horticulture/Plant%20Clinics%20Schedule.pdf.     

Resources:
Broschat, T. K. (2016) Cold Damage on Palms.  The University of Florida Extension Service, IFAS.
Broschat, T. K (2015) Bismarckia nobilis: Bismarck Palm.  The University of Florida Extension Service, IFAS.
Weissling, T. J. & Giblin-Davis, R. M. (2016) Palmetto Weevil, Rhynchophorus cruentatus Fabricius (Insecta: Coleoptera: Curculionidae).  The University of Florida Extension Service, IFAS.


Monday, November 7, 2016

Be ready for roses


My roses always do really well during this time of year.  They are blooming nicely and seem to appreciate our present slightly cooler and drier environment.  While roses produce more flowers in summer, the flowers at this time of year are actually larger and have deeper color.  Not to say roses are without their challenges!   However, if well cared for, roses in our area can bloom all year long.   With some sensible selection, maintenance and grooming, growing a rose will provide cut flowers and beauty in any setting.

You are going to be much happier with your roses if you pick types that are suited for our Florida climate.  Low-maintenance roses such as "old garden roses" and shrub roses such as David Austin Roses® and the “Knock-out®” series require minimal care.  At the other extreme, high-maintenance, modern roses such as hybrid teas, require more grooming, fertilizing, irrigation and pest management.  Selecting roses grafted on Rosa fortuniana (also called 'Double White Cherokee') rootstock will grow larger, more vigorous plants that will produce more flowers and live longer than other roses.  Second to fortuniana is ‘Dr. Huey’ rootstock followed by multiflora rootstock which has the shortest life span here in Florida.  There are some rose plants (the older shrub varieties) that are satisfactory, as are dwarf roses, un-grafted and on their own roots.  Some good low-maintenance roses to try are 'Bourbon', 'China', and 'Bermuda'.  Check local garden centers and nurseries for these roses.  You may also check with regional specialty nurseries and Internet sources.  Also consider communicating with local rose societies and The American Rose Society at http://www.ars.org .

Roses need at least six hours of sun for best results.  The more sun the better, but if some shade is present, it is best to plant roses so that they receive morning sunlight.  This morning sun will help dry the early morning dew off which will help reduce leaf diseases such as black spot.  Roses like a well-drained soil with some amendments added to improve water-holding capacity.  Now, while generally we don't recommend adding soil amendments when planting woody plants, the rose is an exception which will greatly benefit from compost mixed into the upper twelve inches of soil.  Start a regular maintenance fertilizer as soon as new growth begins with a complete fertilizer including micronutrients and slow-release nitrogen for best performance.   As a final touch, good organic mulch will help retain moisture and suppress weeds.  When watering, it is best to apply irrigation to the soil surface so that the leaves are kept dry. 

Keeping a rose plant looking its best will involve some regular grooming and pruning.  Grooming is going to involve light and selective trimming such as removing dead flowers.  This keeps rose hips (fruit) from developing and redirects the plants energy back into the plant for more blooms.  If needed, more major pruning can be accomplished in February with a lighter follow-up pruning in August.  Removal of dead, diseased, damaged or spindly growth will improve the plants form and keep the height in bounds.  Flowers for the vase are best cut after the green sepals at the base of the flower fold back toward the stem and the outside petals loosen and start to unfurl.  Cut the flower with a sharp knife just above a five-leaflet leaf. 

Probably the biggest pest problem in our area is a fungal disease called black spot.  Most low-maintenance cultivars are fairly resistant to this disease.  However, removal of dead and diseased leaves will help as part of a sanitation effort.  Also, mulch will help create a barrier between the rose and the soil level.  Using drip irrigation will also help keep the foliage dry and thus less open to black spot infection.  Fungicides are also available to protect new growth.

Roses are definitely worthy of a spot in your landscape.  For more information on growing roses, please call our Master Gardener volunteers on the Plant Lifeline on Mondays, Wednesdays and Fridays from 1 to 4 pm at 764-4340 for gardening help and insight into their role as an Extension volunteer.  Don't forget to visit our other County Plant Clinics in the area.  Please check this link for a complete list of site locations, dates and times - http://charlotte.ifas.ufl.edu/horticulture/Plant%20Clinics%20Schedule.pdf.  

Resource:
Park Brown, S. (2013) Growing Roses in Florida. The University of Florida Extension Service, IFAS.

We are just nuts about macadamias!


Our Demonstration Garden at the East Port Campus on Harbor View Road in Port Charlotte is a treasure trove of plants.  We try all different types of trees and shrubs at this Demonstration Garden – most are successful and some get composted.  One recent addition was a macadamia tree.  It has been in the garden a few years and this season blessed us with a few nuts!  The macadamia is a beautiful evergreen tree that can be grown in many parts of Charlotte County.  Originally from Australia and then introduced to Hawaii where it really took root, the macadamia can also be grown in California and Florida.

Growing up to forty feet tall, macadamia trees have eight inch long leaves with small spines along the margin edges.  The sweet-scented flowers are white to pink and hang in long racemes over six inches long.   The nut develops within a green husk that eventually opens up to reveal a hard nut.  Once cracked, a white kernel is exposed which, when roasted, provides one of the best nuts known. There are a couple of macadamia species (including hybrids) available.  Commonly called either “smooth shell” (Macadamia integrifolia) or “rough shelled” (Macadamia tetraphylla), macadamias, there are many named cultivars including Hawaiian and California varieties.  ‘Beaumont’ is a noted variety that is good for backyard plantings.  While seeds can be sprouted, it will take upwards to twelve years to produce a crop.  Therefore, it is best to obtain grafted varieties which will begin to produce in as little as two to five years.  In perfect situations, a mature tree could produce upwards of one-hundred and fifty pounds of nuts in the shell.  This of course does not take into account the realities of pesky squirrels and rats.  Expect the nuts to be ripe anywhere from July through November.  Ripe nuts will fall to ground.  As the nuts dry, you will notice that the husk will split open exposing the nut inside.  The nuts are mechanically cracked, allowed to dry and then roasted at two-hundred and seventy-five degrees Fahrenheit either dry roasted or with some refined coconut oil for twelve to fifteen minutes. 



Macadamias do best in full sun and in well-drained soil.  While they can survive in our subtropical climate, mature trees can tolerate temperatures as low as twenty-five degrees Fahrenheit.  Young trees need protection as they can be killed by freezing temperatures.   Once established, macadamia are fairly drought-tolerant but will appreciate irrigation during flowering and fruiting.  Fertilize with a citrus-type fertilizer as per label directions. 

Now, our small success is encouraging, but macadamia nut trees are not without their challenges.  However, as many gardeners could agree, new additions – even the macadamia - could make an interesting and potentially tasty addition to your landscape!  For more information on all types of subtropical edible plants suitable for our area, please call our Master Gardener volunteers on the Plant Lifeline on Mondays, Wednesdays and Fridays from 1 to 4 pm at 764-4340 for gardening help and insight into their role as an Extension volunteer.  Don't forget to visit our other County Plant Clinics in the area.  Please check this link for a complete list of site locations, dates and times - http://charlotte.ifas.ufl.edu/horticulture/Plant%20Clinics%20Schedule.pdf.   

Resources:
Malo, S. E. & Campbell, C. W. (2009) The Macadamia.  The University of Florida Extension Service, IFAS.

California Rare Fruit Growers, Inc. (1997) Macadamia.  http://www.crfg.org/pubs/ff/macadamia.html .  

Luffa – for the bath and the table


We are all familiar with the luffa gourd being used as a sponge for bathing and cleaning dishes.  Did you know that the luffa is also used as a vegetable in some cultures?  Available in both smooth and angled fruit, the luffa is a surprisingly versatile plant.

Originating in tropical and subtropical Asia, the luffa is a member of the cucumber family.  Growing as a vine up to thirty-feet long, a good sized trellis is needed to accommodate these plants which require a long growing season of at least ninety days.  You can either direct seed or start transplants to be put out in the garden at a later date.  Plant in a full-sun, well-drained location after the danger of frost with plants three feet apart and rows six feet apart.  You can expect to get about six to seven fruit per vine.  As the luffa grows, you will notice that they produce both male and female yellow flowers.  The female flowers actually have a small undeveloped fruit at the base of the flower.  If pollenated, these fruits will begin to swell.  The young, tender fruit can be harvested and used raw or cooked with a taste similar to zucchini or cucumbers. 

In order to be used as a sponge, the luffa needs to be fully mature and is best vine-ripened and allowed to turn yellow to brown in color.  Let the luffa dry for about two weeks at which time the skin will be hard and brown.  The large end of the luffa will open, and from this opening, shake the seeds out.  Soak the whole gourd in water overnight which will soften the rind and allow you to peel off the outer skin. Then finish the processing by drying the spongy gourd in the sun.

I have grown luffa locally and they are very squash-like in taste and texture.  Making sponges is also very easy to the point when you might have too many luffas!  Some of the luffa cultivars commercially available would include ‘Smooth Boy’, ‘Smooth Beauty’ and ‘South Winner’ for the smooth types, and angled types such as ‘Lucky Boy’, Hybrid Green Glory’ ‘Summer Long’, and ‘Hybrid Asian Pride’.  The angular luffa has ridges and is dark green in color, tends to have a longer shelve life, and has even been called “Chinese okra” as per their okra-like appearance. 

Luffa is a very easy-to-crow crop that is fun to grow by both youth and adults and produces food, sponges and even craft materials.  For more information on all types of edible ornamentals, please call our Master Gardener volunteers on the Plant Lifeline on Mondays, Wednesdays and Fridays from 1 to 4 pm at 764-4340 for gardening help and insight into their role as an Extension volunteer.  Don't forget to visit our other County Plant Clinics in the area.  Please check this link for a complete list of site locations, dates and times - http://charlotte.ifas.ufl.edu/horticulture/Plant%20Clinics%20Schedule.pdf.  

Resources:
Xie, Y., Liu, G., Li, Y. & Migliaccio, K. (2016) Luffa- an Asian Vegetable Emerging in Florida.  The University of Florida Extension Service, IFAS.
MacKenzie, J.  (2008) Growing luffa gourds. University of Minnesota Extension.
Stephens, J. M. (2015) Gourd, Luffa—Luffa cylindrica (L.) Roem., Luffa aegyptica Mill., and Luffa acutangula (L.) Roxb. The University of Florida Extension Service, IFAS.

Wednesday, October 19, 2016

Downy mildew on viburnum - a disturbing mess


'Awabuki' viburnum is a favored ornamental hedge or shrub noted for its large shiny green leaves useful for screens and formal hedges.  The last few years have seen a new disease organism move into our area and infect these beautiful landscape plants.  The disease known as downy mildew on viburnum, a species specific water mold disease, can make a disturbing mess of these plants.  There are some management techniques for the home landscape that can help lessen the damage.

The 'Awabuki' viburnum is really different than any other viburnum with very large glistening, almost mirror-like leaves.  Homeowners often use 'Awabuki' as a screen around pools or just as an impressive tall hedge.  Downy mildew is a water mold organism that develops when nighttime temperatures range from fifty to seventy-two degrees F.  Mostly occurring from November to March, this downy mildew needs a cool, foggy and humid environment, typical of some nights in our area, to develop.  Most of the damage appears on the newest leaves with yellow specks and reddish brown blotches – almost a bronze appearance on the leaf surface.   On the underside of the leaf, you will notice whitish-grey downy growths.  Soon after, the leaves will often drop with some portions of the plant becoming defoliated – near eighty percent defoliation in severe cases.  The disease can spread rapidly and can be moved about with rain, wind and irrigation.

While you have no control on environmental conditions like high humidity and cool temperatures, you can reduce overcrowding of plants so that there is good air movement.  Remove the fallen leaves which can re-infest plants next year.  Do not provide overhead watering if at all possible – micro-irrigation at the soil level is more efficient and does not wet the leaves.  Do not water at night.  Also, do not over-fertilize as this makes the leaves much more succulent and open to infection.

Chemical treatments can be made with the use of fungicides, but work best when used as a preventative.  Rotating chemical families will help reduce the possibility of fungicide resistance – a real problem if one type of fungicide is used all the time.  Fungicides to use would include copper octanoate, chlorithalonil, and extracts of neem oil, as examples.  Always read the pesticide label as the label is the law.

The 'Awabuki' viburnum is worth protecting from downy mildew.  A bit of cultural practices, possibly augmented with some properly timed fungicides, can help reduce this disfiguring disease.  For more information on the suppression of all types of fungal disease in our area, please call our Master Gardener volunteers on the Plant Lifeline on Mondays, Wednesdays and Fridays from 1 to 4 pm at 764-4340 for gardening help and insight into their role as an Extension volunteer.  Don't forget to visit our other County Plant Clinics in the area.  Please check this link for a complete list of site locations, dates and times - http://charlotte.ifas.ufl.edu/horticulture/Plant%20Clinics%20Schedule.pdf.

Resources:
Palmateer, A. J. (2016) Viburnum Downy Mildew.  The University of Florida Extension Service, IFAS.
Caldwell, D. (2011) Viburnum Downy Mildew Disease on Awabuki (Mirror leaf) Viburnum.  The University of Florida Extension Service, IFAS – Collier County