In Florida almost everyone wants a citrus tree in the yard. They are wonderful to look at and delicious to devour. Most require very little care. Most of the problems that might occur, branch dieback, fruit split, peeling bark, borer attack, root rot and eventual death are all the result of excess watering. Citrus can be watered once every two and a half to three weeks if there is no rain. I would put half-heads on the sprinklers system to throw the water away from the trees. Fertilize in March, June and October with a good citrus fertilizer and enjoy your bounty! 

Q. My pink grapefruit has a bitter taste and is 11 years old. What is wrong? 

A. Excess watering definitely affects the taste of the fruit. Stop all irrigation permanently within the tree's root zone. Cut out any dead wood. The tree could be grafted to sour orange rootstock. If the fruit does not improve in taste with elimination of the water, the sour orange rootstock has overtaken the tree and crowded out the pink grapefruit. 

Q. My navel orange has dry fruit with a thick skin. What is wrong? 

A. The navel tree with dry, thick-skinned fruit has been watered too much. It is best to cap sprinkler heads permanently near the citrus root system because they can get fatal root rot if irrigated along with the lawn. Use half heads to throw water away from the trees if the heads are to the edge of the tree canopy. Citrus need water only if there has not been rain for about three weeks. Then you can use a hose for watering. Most years the trees do fine on the rainfall that nature provides. This is true for established trees in the ground two years or more 

Q. My nine-year-old tangelo had many flowers and just a few fruit. Do you have any idea why this is? 

A. Tangelos may produce heavily one year and take a break the following year. This is known as alternate bearing and is common on some apple trees as well. 

Q. My grapefruit tastes fine but has an ugly spotted skin. What can be done for this condition? 

A. The skin has melanose, a fungal condition. It is unattractive, but does not affect the fruit's taste. Cut off any dead wood. Permanently cap sprinklers under the tree's root zone to reduce the melanose condition and avoid root rot. 

Q. My 20-year-old grapefruit's leaves are curled up and have black dots underneath. We can't control the sprinklers. It is blooming now and has good fruit. Can we save it? 

A. Your grapefruit appears to be suffering from leaf miners and some scale. Do not spray when the tree is in bloom. Spray with Safer's Insecticidal Soap on the undersides of the leaves. 

A. Grapefruit holes are caused by shield-shaped insects called stinkbugs. Harvest fruit early to avoid this pest. Stinkbugs are very mobile, so spraying is pretty useless. Normally they damage only a few fruits and there are plenty left over for the family and friends. The small bugs in the fruit are scavengers and help to dispose of it. They are nature's garbagemen. 

Q. What is eating my young two-year-old citrus leaves? I tried soap spray to no avail. 

A. Sevin is about the only spray safe for insects chewing on citrus leaves. Chances are it is nocturnal caterpillars, leaf cutter bees or beetles chewing on the foliage. Damage is very minor from chewing insects, so I am not inclined to worry excessively about them. I personally would not spray. If you do spray, follow label directions exactly. Do Not Spray if the plants are blooming. Sevin is lethal to bees. If the bees are killed - no pollination - no fruit. Use Thuricide for caterpillars. 

Q. My grapefruit tree has exposed roots. Should they be covered? 

A. You can cover the roots of the tree with extra soil from around the yard as long as you do not add too much. More than an inch or so can cause plants to decline as oxygen is cut off from the roots. 

Q. We did not have a big crop from our grapefruit tree last year. Neighborhood children climb the tree and swing from the branches. Will this affect the tree?

A. Children swinging and climbing in the tree can certainly affect the crop. The shaking of the branches will affect pollination and will cause fruit to fall prematurely. 

Q. We have a 12-foot thorny citrus that finally produced this bumpy fruit with little juice. What is it?

A. Your fruit is rough lemon, which is used as an understock for the fancy citrus top. The understock can sucker around ground level, outgrow the fancy top and shade it out. I think this is what happened to your tree. You can remove it or prune it into a small flowering tree where the sharp thorns will not hurt anyone. 

A. Your young orange seedling was cross-pollinated with another citrus tree to produce your seedling. After six or seven years you should have a tree old enough to bear oranges. Because we do not know what the other parent is, we cannot predict what the fruit will taste like. Chances are it will be okay. Grafting a Valencia shoot to the seedling is the only sure way of reproducing the Valencia qualities you desire. Grafting is usually done in April or May. 

Q. We just moved to Florida and are anxious to plant some fruit trees in our yard. My husband says we should plant fruit trees at least 5 feet apart. What do you say?

A. Five-foot spacing between trees is way too close for any fruit tree to develop properly. The fastest, biggest tree will reach for the light and shade and kill out the other trees through competition. Fruit trees need sun to produce a good crop. Before the other trees ultimately die out; they will be too shaded to set fruit. The remaining tree will be tall and leggy and you will need a tall ladder to get the fruit. Minimum spacing on citrus is 15 feet apart on Meyer lemon, kumquat, and Key lime; 20 feet apart on oranges, tangelos and tangerines; 25 feet apart on grapefruit, and 30 feet or more on avocados and mangos. 

Q. I have an orange tree that is producing fruit and flowers at the same time. Is this unusual? 

A. Young citrus trees often flower and fruit when they are in a stress condition, such as in a container with crowded roots. They may also bloom and fruit initially after planting out in the yard. The young trees often need a few years to establish good root systems and make enough top growth to support a good crop. 

Q. Why didn't my citrus tree produce fruit that was as tasty as the fruit I had last year ?

A. Citrus produce varying crops each year depending on weather, rainfall, pollination, etc. It is like farming and each year is different. 

Q.I have a citrus bush with fruit between an orange and lemon. The fruit is more yellow and the bush is thorny. What is it? 

A. The half lemon/orange is probably sour orange, which is good for marmalade and as a meat sauce for barbecue. 

A. Good tangerine varieties include `Dancy' and `Mineola'. 

Q. My Key lime fruit drops off when it is the size of a pea. What is happening? 

A. Key lime and other fruit trees will abort fruit that cannot carry to term. Young trees and underfertilized trees are most likely to abort fruit. 

Q .My ten-year old lemon tree is suffering from loss of foliage, particularly on one side. I fertilize and sprayed with malathion when I noticed the leaves getting sparse. It receives some water from the sprinkler system but not a lot. What else could be the problem? 

A. You didn't mention insects, so it may be one or a combination of reasons that caused your tree to decline. Your tree could have been girdled with a weed trimmer, which will kill the tree slowly over time. Plant a ground cover such as liriope around the tree trunk to act as a buffer between the weed trimmer and the trunk. The tree may be planted too deep. Tree trunks should show a widened flare where they enter the ground if they are planted at the right depth. Trees planted too deep will have trunks that enter the ground vertically like a telephone pole. Dig carefully with a trowel to the flare on the trunk. Remove excess soil from over the root system to about 3 feet from the trunk until it looks like a dished plate with the tree in the center. This will allow roots to breathe and the tree to recover if it is not too far gone. Because one side of the tree had sparse foliage it could indicate girdling roots. If the roots were potbound when purchased, they will wrap in a spiral around the original root ball. As the trunk expands, it contacts the spiraling roots and cannot grow more. This can stress one side of the tree and cause leaf and fruit drop. The girdling root has to be carefully dug out and cut off. Citrus also suffer from root rot in a lawn setting with regular irrigation. Trees with root rot have splitting, poor tasting fruit; poor foliage, branch dieback and splitting bark borers. They eventually die. 

A. Yes, leaf drop is normal for March. Vigorous new growth and flowers also should be appearing now. If the tree has lost more than three quarters of its leaves at one time, I would suspect root rot and excess water. 

Q. We live on a canal that has a seawall in the backyard. How close to the seawall can I plant a tree? 

A. Keep your trees away from the seawall. These tend to lose soil behind them and need constant repair work. Set the trees at least 6 to 8 feet from the wall. 
 

Citrus Canker (added 27 September 2000)
The citrus canker problem continues unabated in south Florida.  I awoke this morning to a phone call from an irate garden club member who was losing 9 trees because of the canker.  Her trees were healthy but fell within the 1900 foot radius of an infected tree.  

Last Thursday I received my first visit from the inspectors.  My grapefruit received a white X indicating a suspect tree but the pathologist gave the tree a clean bill of health.  This guarantees nothing as they will come back and check again.  Dade and Broward  counties in southeast Florida are now quarantine zones for citrus.  These counties contain the cities of Miami and Fort Lauderdale.  Palm Beach county is next in line for quarantine.The big citrus groves start in the north and west parts of this county are part of a multi-billion dollar industry in Florida. 

I decided to call the Lake Alfred Citrus Research Station in central Florida for more information.  A doctor at the station said that the canker affects lemon, grapefruit, lime, and key lime most severely.  The most resistant citrus types are "Valencia" orange and tangerines and their hybrids.  This doctor did lots of research in Brazil and other South American countries.  Despite the canker a citrus industry still exists in these countries.  They control the canker by using resistant varieties, spraying with Kocide, and using tall dense windbreaks all around the groves to contain the canker.