By: Amy Grant
You have waited and waited and now it looks, smells and tastes like it’s citrus fruit picking time. The thing is, if you’ve tried pulling citrus off trees and are met with great resistance instead, you may wonder “why won’t my fruit come off the tree?” Keep reading to find out why citrus fruit is sometimes so hard to pull off.
Why is Citrus Fruit Hard to Pull Off the Tree?
If your fruit won’t come off the tree easily when harvesting citrus fruits, the most likely answer is because it isn’t ready yet. That’s an easy answer, but one fraught with seeming debate. In a search on the internet, it seems that citrus growers are of two dissimilar minds.
One camp says that citrus fruit is ready when the fruit slips easily from the tree by grasping it firmly and giving it a firm, yet gentle, rotating tug. Another camp states that citrus fruit picking should only occur with the aid of garden shears – that pulling citrus off trees should be attempted at no time as it may damage the fruit or the tree, or both. I can certainly see this being the case if the citrus in question is really clinging to the tree and difficult to pull off.
Both parties seem to agree that color is no indicator of the ripeness of citrus. Ripeness is, in fact, sometimes difficult to assess. Color has some bearing, but even mature fruit may have a hint of green, so this isn’t an entirely reliable determination. Aroma is helpful to determine ripeness but, really, the only trustworthy way to tell if citrus is ripe is to taste it. Harvesting citrus fruits is sometimes a little bit of trial and error.
All citrus is different. Oranges will often fall off the tree when they are ready for harvesting. Other citrus isn’t as easy to read. Some cling to the tree more than others. Look for citrus that has attained a mature size, smell it to see if it exudes a citrusy aroma, and then to be on the safe side, snip it from the tree using sharp gardening shears. Peel it and sink your teeth into it. Really, tasting the fruit is the only guarantee that citrus picking time is at hand.
Also, each growing year is different for citrus. Environmental conditions have a direct impact on how well, or not, the citrus will grow. Optimal conditions result in fruit that is redolent with sugar and heavily juiced. Fruit with a lower sugar content and less juice may be harder to remove from the tree.
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Read more about Citrus Trees
Understand How Cold Temperatures Affect Citrus Trees
Many gardeners have inquired about the susceptibility of citrus to cold temperatures. The winter season has been tough on citrus plants.
It is important to understand how cold temperatures affect citrus trees. Among the citrus types most easily killed or damaged by freezing weather are citrons, lemons and limes. Temperatures in the high 20s will kill or severely damage these plants.
Some gardeners who protected their citrus trees during
the recent cold snap were surprised to see their plants
setting flower buds as temperatures started to warm.
Sweet oranges and grapefruits are somewhat more cold-hardy and usually require temperatures in the mid 20s before incurring major damage to large branches.
Tangerines and mandarins are quite cold-hardy, usually withstanding temperatures as low as the low 20s without significant wood damage.
But, among the edible types of sweet citrus, the satsuma and kumquats have the greatest degree of cold hardiness. Properly hardened bearing trees will withstand temperatures as low as 20 degrees Fahrenheit without appreciable wood damage.
Temperatures at ground level can be several degrees lower than temperatures around the canopy of the tree, especially if there is no wind.
Keep in mind the temperature ranges given above only refer to leaf or wood damage. Citrus fruits easily freeze at 26 to 28 degrees when these temperatures occur for several hours.
A longer duration of freezing temperatures is required to freeze grapefruit compared to sweet oranges.
The particular temperature at which tissue of a given plant will freeze and the degree of the damage sustained are functions of a number of factors in addition to the species and variety involved.
Some of the more important are:
- The freezing temperature reached
- The duration of the minimal temperature
- How well the plant became hardened or conditioned before freezing temperatures occurred (the freezing point of tissue of a hardened citrus plant might be 5 to 6 degrees lower than an unhardened plant)
- Age of plant (a young plant cannot withstand as much cold as a more mature tree) and
- Healthy trees are hardier than diseased trees.
Another complicating factor contributing to observations by some that citrus plants seem to freeze at higher temperatures in some years is the difference between air (ambient) temperatures and leaf (tissue) temperature.
On a windy night with clear or cloudy skies, leaf temperature will be about the same as air temperature. On a cold, clear night with little or no wind movement, however, leaf temperature can easily drop several degrees (3 to 4 degrees) below the air temperature because of supercooling caused by frost.
Thus, under the latter circumstances, while the minimum air temperature on a given night may have only been 25 degrees, actual leaf temperature of the plants may have reached 21 to 22 degrees.
The critical temperature is that of the leaf or fruit and not the ambient air temperature.
Trees with a good fruit crop are less hardy than those with no fruit.
Research data provided by Louisiana State University indicated trees growing on bare ground have a higher probability of survival than trees growing in turf areas.
The heat from the ground can radiate upward into the canopy of trees. The difference in the canopy of the tree can be up to 5 degrees.
In general, it is recommended citrus trees be protected when the temperatures is expected to go below 27 degrees for an extended period.
The good news is before the cold snap, temperatures had been on the cool side for a while and citrus trees had hardened off and were fairly dormant.
Citrus trees can better withstand cold weather when they are dormant.
No immediate action is needed when freeze injury is suspected. There is no benefit to pruning the plant until spring growth commences, and the full extent of injury is manifested. Pruning might actually be counterproductive by stimulating faster bud activity before the danger of additional frost/freeze events has truly passed.
Dr. William Johnson is a horticulturist with the Galveston County Office of Texas AgriLife Extension Service, The Texas A&M System. Visit his web site: Gulf Coast Gardening.
For further information about Aggie Horticulture, see our about page.
The term Aggie Horticulture® and associated logos are registered trademarks of the
Texas AgriLife Extension Service, Texas A&M System.
This may be why your citrus tree drops immature fruit
Here's look at the danger of huanglongbing, a tree disease spread by the Asian citrus psyllid. Wochit
Q: My mandarin tree is dropping its tiny green fruits. Can you tell me why this is happening? The amount that is falling seems to be a lot more than normal.
A: It’s normal for all types of citrus trees to drop some immature fruit at this time of year. This self-thinning is nature’s way of making sure the tree does not become too overburdened with fruit. However, if your tree is dropping a lot of the immature fruit then it could be for one of several reasons. I have listed a few of the most common ones below.
Changes in weather can stress your citrus tree and cause fruit to drop. We have experienced some extremes in the weather the past couple of weeks, with an almost 50-degree difference in temperatures from one day to the next. I’m not sure what variety of Mandarin you have, but the Satsuma Mandarins — while cold tolerant — are very sensitive to the heat and are more likely to drop immature fruit than other varieties when temperatures spike in May and June.
Citrus is sensitive to changes in temperature Redding experienced this spring. (Photo: Leimone Waite, master gardener)
There is not a lot you can do to change the weather, but you can help mitigate the stress on your tree by keeping the tree well-watered when the temperature spikes. If your tree is in a pot, this may mean watering it every day.
Droughted trees can be another cause of fruit drop and, if the lack of water is severe enough or occurs frequently, may also cause leaves to yellow and fall off the tree.
University of California Cooperative Extension professor Nick Sakovich wrote in the U.C. Agriculture and Natural Resources bulletin, “Water stress during the late spring/early summer can cause a yield reduction, otherwise known as June drop (although some drop is normal). Once we get past that period, trees can tolerate substantial water stress without crop loss. However, what will happen if we don't apply adequate water will be a significant reduction in fruit size.”
A variety of problems can cause citrus trees to drop unripened fruit. (Photo: Leimone Waite, master gardener)
To prevent excessive fruit drop from happening make sure to water deeply and frequently during hot spells. Adding a layer of mulch under your tree can help protect the tree from drying out between watering and subsequently protect against the loss of immature fruit.
A nitrogen deficiency can also be the cause of fruit drop. This time of year is when trees need the most nutrients as they are blooming and setting fruit. Mandarin trees need between one and 1.5 pounds of actual nitrogen per year. This works out to a total yearly application of approximately eight to 12 pounds of a fertilizer formulated for citrus. The University of California recommends applying fertilizer in three applications spread out over the spring and summer months. For our climate, I suggest applying these three applications in February, April and June.
Excessive pruning or a severe pest infestation can also cause excess fruit drop.
Helping Citrus Recover from the Freeze
The recent freeze hit a lot of citrus in our area pretty hard. The freeze was deeper and had a longer duration than was predicted. It also came on the heels of a very mild period, which prevented the trees from hardening off. The trees never had a chance to acclimate to the coming cold. In fact many of them had active new growth when the freeze hit. We sort of got “caught with our plants down”! So, what do we do now?
First of all, take a deep breath. I know they look bad, but there are things to consider before we rush out with the pruners, loppers, saws and wheelbarrows. We want to give our trees their best chance to recover. If you rush to prune, you run the risk of cutting away parts of your tree that may recover on their own. In addition, how the tree behaves in the weeks following a freeze can help you read the extent of the damage. If you are too quick to remove the damage, you will lose those clues.
How freeze damage occurs
Freeze damage occurs when ice crystals form in the tissues, expanding and rupturing cell membranes. Not all citrus varieties experience damage at the same temperature some are hardier than others. And not all parts of the tree are affected equally.
Leaf damage will be apparent a few days after the freeze, but twig and branch death from a severe freeze can continue to appear for weeks after a severe freeze. In some cases, the extent of the damage may not appear until the following growing season.
Assessing the damage
The first step to helping our trees recover is assessing the damage. We need to look at the fruit, the leaves and small twigs, and then larger branches and the main trunk.
How readily the fruit is damaged will vary by the thickness of the rind. Citrus with thicker rinds takes much longer to freeze than those with thin rinds. Our grapefruits have gone through several severe freezes over the years, and we have never had the fruits actually freeze.
The cell walls of this freeze damaged orange have begun to break down and collapse. This will result in the juices leaking out and the flesh drying out inside the rind.
The interior of the fruit may suffer damage even though the peel appears normal. Pull a few fruits, cut them open and see if freeze damage is apparent. If it appears that the fruit has frozen, remove it all from the tree. If you do this immediately after a freeze, the fruit can often be juiced and the juice can be frozen for later use.
If the exterior of the fruit has soft or mushy spots it is likely too far gone to save. This will often be noticeable at the stem end first. If it just has brown pitted spots on the skin, check the inside. The damage may be only cosmetic, and the majority of the fruits will be edible, even if they aren’t pretty. If the fruit has any objectionable odor, toss it.
Badly damaged fruit may fall from the tree, but sometimes it will hang on until the frozen flesh dries out inside and the fruit becomes hollow. It is better to remove it by hand than to let it degrade on the tree.
If the fruit does not appear to be damaged, there is no reason to harvest it all at once. You can allow it to continue to ripen naturally. Just keep in mind that a full load of fruit reduces overall tree hardiness a bit.
Leaves and Twigs
Right after a freeze, citrus leaves can appear to be undamaged. If it is a mild freeze, the leaves may just curl up, or “cup”, and feel a bit stiff. They will usually stay that way awhile, and then grow out of it as the weather warms up. But in the case of a deep, hard freeze, the leaves will begin to curl and droop as they thaw out. The newly thawing leaf may look like it has dark “water spots” near the midrib or veins. Tender new leaves will likely turn black, while the older, mature leaves will fade to a soft brown or café au lait color.
This Persian Lime has likely suffered major twig damage as indicated by the dead leaves remaining on the tree long after the freeze. A scratch test has indicated there is live wood farther down the branches. There is no visible bark damage. It is expected that this tree will recover, but will miss a year of fruiting. Pruning will be postponed until March, when most of the twigs will be removed and branch tips will be headed back to live (green) wood.
Leaf drop after the freeze is one way to judge how much twig damage has occurred. If a majority of the dead leaves fall soon after the freeze, the tree is likely to recover. Live wood will shed its damaged leaves through abscission. If the dead leaves cling to the tree for several weeks or more, it is an indication that there is twig death. If the leaves seem to cling for a long time, use the “scratch test” to determine if there is live, green wood working your way down the branches to see where it begins.
Branches and Trunks
When ice crystals expand in the larger branches and the trunk, it causes fractures and splits. The visible signs include splitting bark, loose spots on the bark, and oozing areas that are known as “cold cankers”. Bark splits can be pretty dramatic in older trees, and bark splits in young trees can leave a scar that will last for years. But even this extent of damage does not mean sure death. I have seen citrus cut back to just a short trunk with a few stubs of branches that grew out to be full and beautiful two years later.
Pruning freeze damaged citrus
Once you have assessed your trees, it’s time to make a recovery plan. Don’t rush this! There is no advantage to pruning the damage out right now. It is more a cosmetic preference than what is right for the tree. We are likely to have another freeze event, and Houston is known for warm periods between freezes. We do not want to stimulate new bud growth too early, because those new buds will almost surely be killed in the next freeze.
Wait until mid to late spring before doing any major corrective pruning. Give the trees a light haircut in early March, tipping back until you can see the green cambium at the tips of the cuts. Then wait a few weeks. See what leafs out before you make any major cuts. They can surprise you.
In the most severe cases, you may find that your citrus has been killed all the way to the main trunk. You will need to determine if the grafted variety is still alive. Locate the graft union and scrape the bark of the trunk above it. If it is still green under the bark, the tree is capable of re-sprouting after you cut back all the dead wood. If the variety has been killed, the root stock may still sprout new growth. If it does, you must decide whether to re-graft it in place, or dig it out and start over. This opportunity is the reason we advise banking the graft before a hard freeze. You can lose the whole top of the tree, but if the graft is protected, a new tree will sprout and grow quickly.
Care of damaged citrus
Citrus that has been injured will need adequate nutrition and water to support new growth. Slow release organic fertilizers like Arbor Gate Organic Blend are the best option. This balanced fertilizer contains both the major and the minor nutrients required for healthy new growth. We want to see growth that is steady, but not overly vigorous, as this can lead to more serious infestations of Leaf Miners and Citrus Psyllids, setting back their recovery. Wait to fertilize until late February.
When the new growth begins, start regular applications of a sea-based foliar feed. Foliar feeds have several beneficial effects, including quick mineral absorption and a thickening of the protective surface of the leaf.
Written by Angela Chandler Angela Chandler is a lifelong gardener with a passion for learning and teaching. She tends a ½ acre garden in Highlands, Texas that includes ornamentals, fruits, a small experimental nursery, a flock of Buff Orpington chickens, and a Lab mix named Harley. Her gardening adventures would not be possible without her husband, Fred – always willing to help unload leaves, compost and help build beds. Angela is a member of the Harris County Master Gardener Association – Retired, and a member of the Garden Writer’s Association.
Growing Citrus in Containers
Even if you can’t grow Citrus in your backyard, you can grow them in pots.
Growing your very own citrus fruit is no longer dedicated to those who live in the sunny south, but can be enjoyed by everyone throughout the United States. Growers in colder regions can now happily benefit enjoying potted citrus trees, so it's no longer just the fruits and vegetables in northern climates, now growing your favorite citrus in containers is gaining popularity.
Growing essential crops like oranges, lemons, satsumas, kumquats, and limes add versatility to the home with pleasant fresh citrus fragrance and beauty for years to come.
Citrus trees are especially suited for container growing as they can be kept at manageable sizes. Whether you have the everbearing Meyer lemon, Persian lime or a sweet orange variety, you’ll enjoy the health benefits of your home-grown fresh fruit.
Whether it's growing the lemons for lemon juice for lemonade, or a source of vitamins using the outer rind for lemon peel in recipes, or for freshly squeezed orange juice to build the immune system to fight the common cold, growing citrus trees can be a unique thrilling undertaking.
Trees planted in decorative pots are attractive on a patio or an apartment balcony.
When blooming and fruiting, the appealing eye-catching colors of orange, yellow and greens are sure to please. The scent of spice or hints of citric acid fill the air with rich and robust fragrances that create nature's aromatherapy, plus the added benefits of making lemon oils or other essential oils, growing citrus trees are a uniquely delightful experience.
In colder zones or during freezing weather, take the tree indoors when temperatures at night are below 50 degrees F. These tips can help you on the way to successfully grow citrus trees in containers.
For directions on planting in zones 9-11 only: https://lemoncitrustree.com/store/growing-citrus-ground
Our Citrus can be planted in USDA growing zones 9-11 only.
Trees that are planted in the ground that experience freezing temperatures above zone 8 need protection in unusual inclement weather. Planting in the wrong hardiness planting zone will void the warranty.
Planting zones: https://planthardiness.ars.usda.gov/PHZMWeb/
Pot Size And Re-Potting
Do not re-pot until you have had the tree at least 2 weeks, the tree needs time to adjust
Never plant a tree in a container more substantial than a 10-gallon pot. Always water according to pot size, with a moisture meter. Drilling additional holes in the pot is an easy way to improve drainage.
When repotting DO NOT transplant using stones in the bottom of the pot or use stones on top as a decoration, this will cause a drainage issue and lock moisture into the pot which will cause root rot.
DO NOT USE SELF-WATERING POTS OR GLOBES.
DO NOT USE POTS WITH DRAINAGE TRAY ATTACHED.
Select the right sized pot with adequate drainage holes. If the pot has no holes on the side or bottom, it is not the correct pot for planting.
Self-watering is incorrect watering, self-watering is not infrequent deep watering.
Place the prepared soil mix in the bottom of your new container. Gently slide tree roots out of the old container, as the tree slips out of its old container it will retain the shape of the container it was in.
Try to retain the shape of the container, you can detangle any circling roots near the bottom of the root mass so that growth in the new pot will not be impeded but do not break up the top portion of the soil near the woody area of the tree. The woody area is the root crown area.
When setting the tree into the new container, do not allow the tree to slide deep into the pot. The top portion of the old soil surrounding the woody area of the tree should be just a few inches below the rim of the new container. NEVER ADD ANYTHING TO THE TOP OF THE SOIL , if the tree falls too far down into the new pot, remove the tree and add more soil from the bottom NEVER THE TOP!
Once the tree is adequately placed in the new container only add soil to the sides around the rim of the pot, building the soil line to meet the level of the root crown soil.
Set-up ideas for your potted tree can be found here: https://lemoncitrustree.com/store/citrus-blog/2016/12/16/easy-setup-ideas-for-indoor-citrus-trees/
Never plant anything in the pot with the tree. An assortment of decorative plants look attractive in the pot with the tree, but other plants will rob the tree of moisture and nutrients.
Do not place decorative rocks on top of the soil after planting. This can cause serious problems over time due to the pot not drying out properly which causes root rot.
Do not bury the root-crown with soil or mulch. A photo of the root crown can be found here: https://lemoncitrustree.com/store/pest-disease
Deep Watering Method For Potted Trees
Trees will die if they don't have the essential requirements, incorrect watering is the most common cause of issues and tree death.
1. Check the tree with a moisture meter before watering.
2. The prong should be deep into the pot.
3. Only water when the meter reads 4 (for a meter with a range from 1-10).
4. All trees require deep watering. Deep watering is drenching the soil until water pours from the holes at the bottom of the pot.
5. Watering with a few cups is not acceptable, this will cause deep roots to die. Never be stingy with the water when the tree needs to be watered.
6. Once the tree has been watered properly, check it with a moisture meter again to make sure the meter reads high (9 or 10) and then do not water again until the meter reads 4.
7. In the winter you will water far less, about twice a month (But always check the tree with a meter weekly because this can vary)
8. The meter should never be left in the pot when not in use.
9. Never water with cold water in the winter
10. Never water the tree with water from a water softener.
NEVER ALLOW TREES TO SIT IN STANDING WATER
A space between the bottom of the pot and the tray that catches the water is required.
We recommend using commercially available potting mixes. Miracle-Gro Palm, Cactus, Citrus soil is a soil mix that is lightweight and drains well.
Rosebush garden soil mixes (formulated for outside use) work well.
Provide eight or more hours of direct sunlight per day. If less than six hours of natural full direct sun is provided, supplement with grow-lights. Usually, an unobstructed south or southwest facing window is ideal. Suggestions on lighting can be found here- https://lemoncitrustree.com/store/citrus-blog/2015/10/05/winter-recommendations-for-inside-citrus/
Avoid placing your tree near a heat vent.
Citrus trees feed heavily on nitrogen. Your fertilizer should have more nitrogen (N) than phosphorous (P) or potassium (K). Use at least a 2-1-1 ratio.
In some regions, you may be able to find specialized citrus/avocado fertilizers. Any citrus formula will contain trace minerals like iron, zinc, and manganese. Many all-purpose and commercial organic products will work.
Never use fertilizer stakes for a tree planted in a pot, fertilizer stakes can burn fine root fibers.
Fertilizers come in different strengths, release rates, and application schedules, so follow package instructions carefully. We recommend that you fertilize more often than recommended due to nutrients getting washed out of the pot when watering.
Yellowing leaves indicate lack of fertilizer, overwatering, or a pest infestation.
For fertilizing suggestions: https://lemoncitrustree.com/store/citrus-blog/2015/08/11/feeding-recipe-for-a-happy-tree/
Know where the graft union is on your tree. It can usually be seen as a diagonal scar, a branch off-set or a knobby area between four and eight inches from the soil. Remove all shoot growth below the graft.
Growth below the graft will take vitality from the tree. It is essential to remove them as soon as they are observed, left to grow they will eventually kill the tree.
Photo of Graft here: https://lemoncitrustree.com/store/pest-disease
Juvenile fruiting wood will sometimes have thorns this is a young tree's way of defending against grazing animals. As the tree matures, thorns will not appear as often. Prune off thorns if desired.
Pest prevention is a necessity with trees that produce food.
Insects are attracted to food and your tree is a sweet source of food for scales, aphids, or mites etc.
If your tree is infested with a pest you must wash your tree with Dawn dish soap and warm water, scrubbing with a washcloth. Make sure the topside and underside of leaves are entirely washed and scrubbed of sooty mold and cleanse of any sticky substance. You can use a toothbrush in hard to reach areas, such as a crevice at the Y part of a branch.
Treat the tree once it is clean with a horticultural oil or neem oil.
It is IMPORTANT that the honeydew is removed from branches and foliage because it is the honeydew that will eventually kill the tree.
Over-wintering your citrus trees indoors will be necessary if you live in a colder region. When temperatures fall below 50 degrees F at night place your tree indoors in a southern sunny window.
Please contact us at [email protected] or call if you need assistance.
Lemon Citrus Tree