Why Are There No Flowers on My Azalea?

It’s easy to understand the popularity of a plant like the azalea. Versatile, graceful and a profuse bloomer - azaleas have it all. Unless your azaleas stop blooming suddenly, which can be a major disappointment. There are several possible contributing factors that may be attributed to this lack of flowering. Most often it is a combination of not enough sunlight, bad weather and improper pruning or fertilization.

Sunlight - Azaleas perform best in filtered sunlight. However, do not over-shade. Azaleas placed in a location with too much shade will produce few to any flowers and will gradually grow increasingly leggy in form. Preferably, plant azaleas under trees with high crowns and widely spaced branches.

Weather - Too much cold weather, too little cold weather or unseasonable weather conditions can impact azalea blooming considerably. Here in the south, if temperatures do not stay at 50 degree Fahrenheit for at least four consecutive weeks azaleas may fail to bloom. This is known as the chilling requirement of azaleas. For this reason, azaleas should not be planted in south Florida or other locations where these temperatures are not met. On the other hand, in the north, cold weather can prevent azaleas from blooming by killing tender blooms on the plant before they have a chance to open. Unseasonably warm weather may cause azaleas to bloom too soon, often referred to a “bud blast”, only to be killed by later cold weather.

Pruning - While pruning is recommended to create and maintain a desirable form, be careful not to undertake this activity too late in the year. Next year’s flowers form in late summer to early fall. Prune azaleas just after they have finished flowering for the year, ideally no later than mid-June.
Fertilization - Avoid nitrogen-rich fertilizers, which spur leaf and branch growth but suppress blooming. If necessary, fertilize azaleas during the spring or fall using small amounts of granular, slow-release fertilizer. In general, apply a phosphorus-rich formula to increase flower production.

References:
Azalea Society of America; Azalea Questions; May 2008
University of Florida IFAS Extension; Azaleas for Florida; Dewayne L. Ingram et al.; October 2003
The United States National Arboretum; Azalea Questions and Answers; April 2009
Osceola County Extension Service; Azaleas Need Care; Jennifer Welshans; June 2005
What Would Cause My Azaleas Not to Bloom?; Christine McLachlan; March 2011

Judas Tree and Eastern Redbud - Same Thing?

Not exactly, although the two ornamental landscape trees are close, but geographically distant, cousins in the plant world. The Judas Tree (Cercis siliquastrum) is also called the Mediterranean redbud. It takes its name from its native habitat, where it is common. The Eastern redbud (Cercis canadensis) is somewhat more hardy native to the United States. They both serve similar decorative landscape functions within their respective regions.
Plant Description - The Judas tree grows up to 36 feet in height and 30 feet in diameter. It is a single-stemmed, slender tree. The Judas tree produces early spring flowers 3 to 5 inches in length. New leaves are reddish purple in color. The Judas tree is prized for its showy buds and bright rose-colored flowers that will appear before leaves in the spring. Its heart-shaped leaves and dark-colored bark also also atttactive.
Site Requirements - The Judas tree is an eastern Mediterranean native that tolerates a wide range of soil, with the exception of wet, clay soil. Above all else, it thrives in moist, fertile, well-drained soil. The Judas tree prefers partial shade to full sunlight and can withstand temperatures as low as 5 degrees Fahrenheit.

References:
Notulae Botanicae Horti Agrobotanici; The Effects of Different Acid Treatment and Stratification Duration on Germination of Cercis siliquastrum L. Seeds; Murat Zencirkiran et al.; February 2009
African Journal of Agricultural Research; Some engineering properties of Cercis siliquastrum
Natural History Museum; Cercis siliquastrum (Judas tree); Fred Rumsey
What Is A Judas Tree; Christine Mclachlan; March 2011

The World’s Largest Blueberry

The Chandler blueberry bush is a large, attractive shrub that is probably best known for producing the world’s largest blueberry. Blueberries on this plant are between 1/4 inch and 1 inch in diameter. Fruit on mature plants is about the size of a quarter. Chandler blueberry plants also have the longest ripening season of any blueberry cultivar, providing 6 weeks of juicy, delicious fruit during the late summer. The Chandler blueberry is highly pest- and disease-resistant and self-pollinating.These vigorous, upright bushes grow 5-7 feet tall and provide consistently high yields within US Hardiness Zones 4-9.

Site Selection - Chandler blueberries require acid soil, ideally with a pH between 4.2 and 5.2. Place in full sunlight for optimal fruit production. While Chandler blueberries are self-pollinating, cross-pollination tends to produce higher fruit yields. Place at least two different varieties, with similar bloom times, in close proximity to one another.

Pruning - Pruning limits the plant size and encourages a good balance of fruit and vegetative growth.Prune the Chandler blueberry bush annually in the winter beginning the third year after planting.  Remove about a quarter of the oldest branches, called canes, during each pruning session.

References:
The Size of a Chandler Blueberry Bush; Christine McLachlan; February 2011Mississippi State University; Establishment and Maintenance of Blueberries; John H. Braswell; 2009
University of Florida IFAS; Blueberry Gardener's Guide; Jeff Williamson and Paul Lyrene; April 2004
University of Connecticut Plant Database: Vaccinium corymbosum

What To Do With An Orange Tree During A Freeze

Orange trees are able to grow in USDA Hardiness Zones 9-11. However, if planting within zone 9a, select a cold-hardy variety of orange tree, such as the sweet or naval orange, or an early ripening variety, such as the Hamlin or Marra orange. If possible provide the tree with a southwestern exposure and be prepared to extend occasional protection from cold weather if temperature fall below 28 degrees Fahrenheit for more than 4 hours (this is technically a hard freeze). Protect orange trees from frost by trapping heat from the ground. Ideally, the entire tree should be covered with a blanket or cloth. If the tree is too large to cover, securely wrap the trunk of the orange tree with blankets from the ground to the first main branching. Remove all mulch from the surrounding area - bare dirt radiates more heat. In fact, while we are on the topic of mulch, don’t ever use it around citrus trees. Period. Citrus trees are prone to foot rot, which causes peeling bark and rot rot. Mulch only exacerbates this problem.

Damage - During a frost ice crystals will form on the tree and the fruit. Severely frost damaged woody parts of the plant will appear dark-brown in color and water soaked. Young trees can die from this - but, fortunately, mature trees rarely do. Any fruit on the tree will become damaged as well. Ice crystals actually form within the orange peel, which will cause the fruit top dry out. Oranges immediately removed from the tree can be squeezed for juice or eaten. If left on the tree, the fruit will deteriorate within a couple of weeks. 

References:
University of California: Frost Protection for Citrus and Other Tropicals
University of Florida IFAS Solutions for Your Life: Fruit Crops

Red Fern Alternatives

The red fern plant, made popular by the American literary classic “Where the Red Fern Grows,” is a mythical plant that does not actually exist. The author, Wilson Rawls, explains that the title of the book is taken from a Native American legend. According to the legend, long ago a boy and girl froze to death in a blizzard. Months later, their bodies were discovered. In between their bodies grew a red fern. The legend states the significance of the red fern, which is - red ferns never die, they can only be planted by an angel and their presence makes a spot holy. The story of the book is pretty much unrelated, but what’s pertinent to this article is that at the end of the book, the main character goes to the spot where his dogs are buried and discovers a red fern growing between their graves. The fern’s presence gives him the strength to move on and begin to heal. Since the publishing of the book, many people have sought out red ferns to plant at graves, or as to give as gifts to those who have lost a beloved pet. There are ferns that have red stems, veins or ferns that are generally reddish in color that may be used to represent a red fern plant.

Red Fronds - The Autumn fern (Dryopteris erythrosora) has fronds that appear red in color when young. In addition, it turns red seasonally. The best color is displayed in the spring and fall. The mahogany fern (Didymochlaena truncatula) also produces reddish mahogany colored new growth that turns green with age.

Red Stems and Veins - Ferns belonging to the genus Athyrium display pleasing colors and offer delicate foliage. Some of the more popular and readily-available species include the Japanese painted fern (Athyrium niponicum), eared lady fern (Athyrium otophorum) and the red-stemmed lady fern (Athyrium filix-femina). Each have dramatic maroon-red stems and veins.

References:

Where the Red Fern Grows; Wilson Rawls; 1961

What Is a Red Fern Plant?
University of Florida IFAS Extension; Dryopteris erythrosora Autumn Fern, Japanese Shield Fern; Edward F. Gilman; June 2007

Why Are All the Ash Trees Dying?

Ash trees are temperate and subtropical trees found in cities, suburbs and natural forests throughout the Unites States. They are characterized by opposite branching, oar-shaped fruit, and compound leaves. Of the 8 billion ash trees in North America, which comprise 16 different species, all are at risk from the destructive beetle known as the emerald ash borer. Nationwide, millions trees have all ready died.

The emerald ash borer is an invasive beetle from Asia. The borer is able to destroy tree tissue undetected under tree bark. Eventually, the canopy of an infected tree thins out and dies back. The root system is deprived of nutrients, and the tree starves. Trees die within 4 years of first diagnosis. There are no disease resistant species and there is no cure once trees are infected. Emerald ash borers are able to fly up to a half mile from infected ash nursery trees, logs or firewood.

Note: Symptoms of emerald ash borer are quite similar to ash yellowing, which is an incurable disease cause by a phytoplasma and spread by phloem-feeding insects. If you suspect your ash tree is infected with either contact a tree specialist immediately for a proper lab diagnosis.

　

References:

Emerald Ash Borer; Frequently Asked Questions; Deborah McCullough, et al.; February 2011

The Connecticut Agricultural Experiment Station; Ash (Fraxinus) Plant Health Problems; April 2007

University of Florida IFAS; Fraxinus Americana, White Ash; Edward F. Gilman, et al.; December 2006

 Can Ash Trees Get Dutch Elm Disease?

　

　

　

Brazilian Pepper - Good For Nothing?

Not exactly. I'm certainly not a fan of the plant, so let me explain. Brazilian pepper is a highly invasive, aggressive and prolific shrub that is found in subtropic regions around the world. Here in the United States it is found in Florida, Texas, California, Hawaii, Louisiana and the commonwealth of Puerto Rico. It is a relative of the poison ivy. It causes severe skin irritation, sinus and nasal congestion, sneezing, eye irritation and headaches. There are reported deaths of birds and grazing livestock following consumption of the leaves and fruit.

 

Environmental Impact (why everyone hates it) -The Brazilian pepper is a disturbed site pioneer - this includes rights-of-way for roads, powerlines and canals. Once established, it will quickly invade adjacent land, while at the same time displacing native plants. Its establishment success has resulted in expansive areas of Brazilian pepper mono-cultures, completely lacking any form of plant and animal biodiversity. A large part of the Florida Everglades is threatened by the species.

Possible Uses (using lemons to make lemonade) - Brazilian peppers are not desirable plants. The state of Florida has a management plan in place that seeks to eradicate the species. However, there are some uses for the destroyed plants. The wood quality of these shrubs is poor; however, it can be used to make small products such as fence posts, toothpicks, and organic mulch (from male plants only). In addition, despite its toxic properties, the Brazilian pepper is a notable source of nectar and pollen for bees in Hawaii and Florida. From it, local bees produce a vaguely peppery tasting low-grade honey.

References:

Florida Exotic Pest Plant Council; Brazilian Pepper Management Plan; Recommendations from the Brazilian Peppertree Task Force; J.P Cuda, et al.; April 2006

University of Florida IFAS Extension; Brazilian Pepper-tree Control; Ken Gioeli, et al.; February 2009
Are Brazilian Pepper Trees Toxic?

Do Fig Trees Need Wasps?

There are four types of figs: Caprifigs, Smyrna, San Pedro and common types. Each type has a distinct method of pollination. Without pollination, fig blooms will not develop. Caprifigs produce inedible fruit and are only used as a pollen source. Smyrna and San Pedro fig trees require the pollen of the Caprifig and the presence of fig wasps to bloom. In the case of both of these species, only the tiny fig wasp is able penetrate the enclosed inflorescence and propagate the fig. In turn, these wasps require the fig as a breeding space - they can actually breed no where else. Each species is completely dependent on the other for survival. Self-pollinating common fig trees do not require Caprifigs or fig wasps to bloom. Common figs cultivars, with a closed ostiole, are recommended for residential use.

References:
University of Florida IFAS Extension: The Fig; Peter C. Andersen and Timothy E. Crocker, March 1994
Purdue University: Fig; Julia F. Morton; 1987
Why My Fig Tree Doesn't Bloom