Dooryard Citrus: To Prune or not to Prune

Dooryard Citrus: To Prune or not to Prune

Citrus: Bearing Branches. Image Credit Matthew Orwat, UF/IFAS

Citrus: Bearing Branches. Image Credit Matthew Orwat, UF/IFAS

Many dooryard fruit growers have asked me this Fall: When is the correct time to prune citrus? How do I prune Citrus right now?  The answer may seem obvious, but when we delve into the question further, we find out that it is not.

Two different pruning strategies exist depending upon the citrus plants age. When training young citrus plants, it is essential to develop three to four main scaffold branches with wide crotch angles. This is done by selecting branches growing different directions that intersect with the trunk or each other at the widest angle possible. Other branches need to be pruned off and these need to be left alone to develop into the main scaffold.  Once the branching system has been developed, traditional heading back, as seen in peaches and apples, is unnecessary.

Young Citrus Tree with good vase shape

There are several instances in which pruning mature citrus trees is beneficial. First, branches should be pruned approximately one foot off the ground so developing fruit is not sitting on the ground. This also helps with weed control and fertilization. Next, it is important to remove growth that is positioned extremely upward or inward to promote an open, vase-shaped habit. Finally, it is necessary to remove any dead wood resulting from winter dieback.

Many growers are eager to remove branches that have been bent downward by heavy citrus crops. This is not necessary; they will bear well in subsequent years.

The last pruning item to consider is removal of suckers from below the rootstock. If the tree is grafted, this is necessary so that the rootstock does not overtake the scion cultivar. Trees propagated from seedage or cuttings will not need this type of pruning since root suckers will be true to type.

It has been noticed that when trees are not over pruned, they exhibit greater cold hardiness. Keeping that in mind, any pruning of citrus should be done at the beginning of March or later, not in the fall or early winter.  With proper pruning practices, gardeners should expect healthy trees with bountiful harvests. For further information please consult the publications listed below or contact your local Extension office.

Citrus Culture in the Home Landscape 

Cold Hardy Citrus for North Florida 

Louisiana Home Citrus Production Manual 

Sugar Belle Mandarin: A Great Choice for the Florida Panhandle

Sugar Belle Mandarin: A Great Choice for the Florida Panhandle

image of sugar belle mandarin

Sugar Belle mandarin cultivar. Mix of sweet Clementine and Minneola varieties. UF/IFAS File Photo.

Florida is known for citrus and many homeowners love to grow and enjoy it. However, a devastating disease known as citrus greening or HLB has taken a toll on commercial and residential citrus since it first was discovered in Florida in 2005.

Sugar Belle is a cultivar of mandarin citrus developed by the University of Florida citrus geniuses and is tolerant of citrus greening disease if it is properly planted and cared for. Tolerance of the disease does not mean that it doesn’t get citrus greening, rather it means that this cultivar can get infected but still be healthy and productive. The fruit of infected trees is safe to eat as the bacterium that causes it does no harm to humans.

Our chilly winters can be detrimental to many kinds of citrus, but Sugar Belle can withstand temperatures down to 14°F once the tree is well established. That is good news for us in the panhandle. Even so, it is best to choose a spot in your landscape with a southern exposure, preferably with a wind block from northwest winds. Avoid low areas as cooler air falls into those areas.

Symptoms of citrus greening on leaves show a blotchy mottled pattern. UF/IFAS photo.

Make your purchase from a certified nursery to make sure you are getting the right cultivar and a disease-free tree. Spring and fall are the best seasons of the year to plant citrus. When planting, make sure to make slices in the rootball if it is rootbound or if circling roots are present. The rootball should be slightly above the ground level after planting. All weeds and grass should be removed under the canopy of the tree to as they compete for water and nutrients with your newly planted tree. Never place mulch against the trunk as it can hold moisture there and promote disease. Water often the first year until well-established; after establishment citrus has some drought tolerance and may only need supplemental irrigation in times of heat and drought.

A good quality citrus fertilizer with micronutrients is crucial for a healthy tree with good quality fruit. The first fertilization should be about 3 weeks after planting and then follow the label directions for subsequent fertilizations. Newly planted trees should be fertilized 6 times in the first year and the fertilizer should be evenly broadcast under the tree canopy.

The only pruning in the first 3 years should be the removal of suckers that grow from the base, water shoots that grow quickly and straight up, and dead wood. Be sure to clean your pruning tools before and after each tree to avoid spreading any possible disease. First rinse off any dirt or other organic matter and then use a 3% bleach solution or alcohol for sterilization.

Happy Gardening!

For more information:

UF/IFAS Research on Development of Sugar Belle YouTube

Citrus Culture in the Home Landscape

Citrus Greening

 

Be Patient with Key Limes

Be Patient with Key Limes

Growing Key Limes in the home landscape is not only a fun and unique addition, but is also delicious – any way you slice them.

The key lime, Citrus aurantifolia, originated in southeast Asia. Genetically speaking, the key lime is likely a tri-hybrid cross between the “odd ball fruits”, known as citron, pummelo and a microcitrus species, Citrus micrantha. There is little commercial key lime production nowadays in Florida, but the fruit remains a very popular landscape option.

The key lime is a small, bushy tree that makes harvest and pruning a breeze. Like most citrus, it’s self-pollinating. The key lime is also an ever-bearing fruit, so there is no real seasonal harvest. The tree could technically bloom any month of the year. There are very few varieties, as trees mostly come from true seed or air layering.

Key Lime fruit at various degrees of ripeness. Photo courtesy of Ray Bodrey, UF/IFAS Extension Gulf County.

Climate is an important factor when deciding to plant a key lime. They are sensitive to cold temperatures, especially below freezing. For the Panhandle, it’s wise to keep key lime trees as patio citrus. In other words, keep the trees in pots so that they can be moved indoors for protection during the winter months.  In the ground, trees should be planted in an area where there is a significant wind block.  Once a few years have passed and tree has become more mature and acclimated to the environment, they may be able to survive on their own, though it is recommended to cover the tree under sub-freezing temperatures. However, it is important to remember that sunlight is a catalyst for citrus fruit production, be sure to plant the tree in an area with full sun.

The usual suspects of citrus insect pests apply to the key lime also. Citrus leaf miner and mites are the most common culprits. Horticultural and insecticidal oils will certainly help to combat these threats. For planting, key lime is well adapted to a variety of soil conditions in Florida. Be sure to water newly planted trees every other day for the first week and then one to two times a week for the first couple of months. Water periodically after that, making sure the soil doesn’t stay completely dry for long periods. A 6-6-6 fertilizer works great for the key lime. Please follow the fertilizer schedule found in the UF/IFAS EDIS publication, “Citrus Culture in the Home Landscape” by Robert E. Rouse and Mongi Zekri: https://edis.ifas.ufl.edu/pdf/HS/HS132/HS132-11822781.pdf

A final interesting thing about the key lime is the ripening stages of the fruit. Because key limes are ever-bearers, blooms can develop at sometimes widely varying times. This causes an uneven development of fruit across the tree. Be sure to wait until the fruit turns begins to turn yellow before harvest. That’s when it’s mature to eat!  Fruit can be stored for up to a week in the fridge or can be juiced and stored in the freezer for later use.

Please contact your local county Extension office for more information. Happy Gardening!

Information for this article can be found in the UF/IFAS EDIS publication, “Key Lime Growing in the Florida Home Landscape” by Jonathan H. Crane: https://edis.ifas.ufl.edu/publication/CH092

UF/IFAS Extension is an Equal Opportunity Institution.

Dooryard Citrus: To Prune or not to Prune

Citrus Spotlight: ‘Parson Brown’, A Unique Sweet Orange

The Sunshine State produces a wide selection of citrus, with a number of varieties that can be grown right here, in your Panhandle dooryard. And, what is more satisfying than picking fresh fruit from your very own trees? So, are you looking for a different variety to plant? The ‘Parson Brown’ sweet orange may be of interest. It can certainly add uniqueness to your dooryard citrus grove.

Originating in China, orange varieties began being introduced in Europe in the fifteenth century. As for introduction to America, Columbus brought orange seeds to the new world on his second voyage in 1493. The first plantings in Florida were around 1513 in the settlement of St. Augustine. For the ‘Parson Brown’, a chance seedling originated at the home of Reverend N.L. Brown near Webster in 1856. Sumter and Seminole counties are still home to some of the largest densities of ‘Parson Brown’ orange trees in the state.

Parson Brown Sweet Orange

Figure 1: ‘Parson Brown’ Sweet Orange. Credit: D.P.H. Tucker, Ray Bodrey, UF/IFAS.

The Parson Brown, however, is often overlooked. The most popular dooryard sweet orange varieties grown throughout Florida are Navel, Hamlin, Valencia and Pineapple. Availability of this variety in our region is not easily found either, as you may have to search to find a tree.

Unlike the short, round appearance of many citrus trees, the Parson Brown tends to grow tall and slim. The Parson Brown’s more upright tree structure is very distinctive. A specimen will certainly stand out in a grove. The fruit and yield rival a Hamlin orange, particularly when grown in heavy, hammock soils rather than sandy soils with low organic content. The variety is also not as marketable as the Hamlin on a commercial level, due to the heavier seediness. You can expect at least 10 seeds per fruit. Average diameter of fruit is between 2 ½” to 2 ¾”. Harvest season for fruit is generally between October and January. Evidence suggests that along with the ‘Sugar Belle’ variety, the ‘Parson Brown’ may be more disease resistant, specifically more tolerant to citrus greening. HLB or citrus greening is a disease that has devastated both commercial production and dooryard citrus across the state.

Contact your local county extension office for more information. Also, for more information on growing citrus in Florida, see the UF/IFAS Extension EDIS publication, “Citrus Culture in the Home Landscape” by Robert E. Rouse and Mongi Zekri.

UF/IFAS Extension is an Equal Opportunity Institution.

Got Citrus? Watch for Citrus Canker

Got Citrus? Watch for Citrus Canker

Citrus canker symptoms on twigs, leaves and fruit. Photo by Timothy Schubert, FDACS

Citrus canker was found for the first time in the Florida panhandle in Gulf Breeze in southern Santa Rosa County in November 2013. Since that time, citrus canker has spread widely in the Gulf Breeze area and just recently in 2020 was found in two locations in Panama City and Panama City Beach in Bay County.

Citrus canker is a serious bacterial disease that only infects citrus trees. It will not infect any other plant species nor is it a threat to human health. Severely affected trees experience substantial leaf loss and premature fruit drop and serve as a source for infecting nearby citrus. The disease spreads through wind, rain, and transportation of infected plant material from other locations.

This highly contagious disease has no cure although progression of the disease can be slowed through the use of copper-based products. This publication guides the homeowner on using copper.

Citrus canker lesions on leaves are raised, rough and visible on both sides of the leaf. Photo by Timothy Shubert, FDACS.

Not all citrus varieties are equally susceptible to this disease. Grapefruit, lemon, and lime are some of the most vulnerable while tangerine and tangelo varieties are among the most resistant.

What should you do if you suspect your citrus is infected with this disease?

  1. Look at this guide for more information and compare the symptoms on your tree to the photos. Lesions on the leaves penetrate through the leaf so they are visible on the upper and lower leaf surfaces, are rough, and have a yellow halo. The lesions look similar on the fruit and stems. Lesions (or cankers) on the stems usually indicate a longer standing infection of a year or more.
  2. Consult your local Horticulture Extension Agent to confirm the diagnosis and obtain more information and control/removal strategies.
  3. Proper removal of infected trees is recommended to prevent the spread of citrus canker but is not mandatory. The best way to dispose of infected trees is through cutting them down and burning them onsite; this ensures than none of the plant material leaves your yard to infect other areas. Consult your local burn regulations before burning. Stray leaves, branches and fruit should be raked and burned or double bagged for the trash. Please avoid disposing of any of your citrus trees by putting them by the side of the road for pickup by the county yard waste recycling or regular waste disposal. The bacterium will survive in the plant tissue and be spread to other neighborhoods in the county. You can, however, double bag infected plant material in sturdy bags and place it in the trash.

 

For more information please see:

UF IFAS Gardening Solutions: Citrus

Citrus Culture in the Home Landscape

UF IFAS Extension Online Guide to Citrus Diseases  

 

Shiranui Mandarin: Ugly Fruit, Great Flavor

Shiranui Mandarin: Ugly Fruit, Great Flavor

Shiranui mandarin

You’ve likely seen them in the grocery stores, and you’ll see them now through April. A large, lumpy (some may say ugly) piece of orange fruit with a bump near the stem. But what exactly is this special looking fruit? It’s a Shiranui mandarin!

The name ‘Shiranui’ is the generic term for this variety of citrus. You may have seen the same variety of mandarin marketed in grocery stores as ‘Sumo Citrus’ which is a trademarked name for the variety. In Japan, they are widely known as ‘Dekopons’. No matter what you call them, they are easily recognized by their distinctive appearance.

The Shiranui mandarin is a hybrid between a Ponkan tangerine and a Kiyomi Tangor (sweet orange x satsuma mandarin). They are easy to peel, sweet, and seedless. Shiranuis are considered to be one of the sweetest and most flavorful varieties of citrus on the market. The fruit are large and have a large protruding bump near the stem that resembles the top knot hairstyle of a Japanese sumo wrestler (hence the trademarked name ‘Sumo Citrus’).

While the majority of Shiranui mandarins on the market are grown in California, the variety can be grown here in Florida and several citrus growers in North Florida and South Georgia have began to experiment with plantings in the region. Homeowners, too, can try their hand at growing the variety as many Florida certified citrus nurseries carry the variety. For more information on different citrus varieties, contact your local UF/IFAS Extension Agent.