I love growing citrus trees because I think they look beautiful in a pot and, of course, produce the most delicious fruit. However, a common problem that comes up (that I experienced myself) is that the leaves can fall off either suddenly or slowly over time.
So, I investigated the different causes of this and revived my leafless orange tree back to health. Fortnutanley, I can report that my orange tree has been saved, and I have detailed the steps I took in this article…
Most often, Orange trees lose their leaves because of low temperatures, drought, or a lack of soil fertility. Orange trees need mild temperatures in Winter and lose their leaves in temperatures lower than 50°F (10°C). Dry soil also causes the leaves to curl up, turn yellow, and fall off.
The classic problem is that orange trees often lose their leaves when brought indoors for Winter (If you live in a cool climate like me) due to the sudden contrast in humidity, temperature, and sunlight.
However, If your orange tree is losing leaves in Summer, then, I discovered this is most often due to underwatering, overwatering, or a lack of nutrients in the soil.
Keep in mind that whilst orange trees are not deciduous, they often drop some leaves in Winter, even when grown in the perfect conditions.
To save my orange tree that is losing leaves, I replicated the conditions of its preferred Mediterranean environment with full sun, mild temperature, moderate humidity, and moist yet well-draining soil in my garden. The leaves of my tree regrew once the conditions were more favorable.
Keep reading to learn why your orange tree is losing leaves and how I saved mine…
Orange Trees Drop Their Leaves When Temperatures are Below 50°F (10°C)
To learn how to save your tree, it is important that we understand how orange trees grow in their natural environment so we can emulate these conditions in our gardens…
Orange trees are native to subtropical climates and have been cultivated to thrive in Mediterranean environments where they are grown outdoors all year due to the mild Winters.
Orange trees are not cold or frost-hardy, so you need to plant them in pots (this is what I do) and move them indoors when the temperature at night is forecasted to be under 50°F (10°C) or lower. Otherwise, the orange tree is likely to lose its leaves or even die back due to frost.
In my research, I spoke to commercial citrus tree growers and learned that citrus trees of all types do become hardier and more resilient to cool temperatures as they mature (particularly those with wider trunks), whereas smaller, less mature orange trees can be much more vulnerable to leaf drop from cold temperatures.
Important tip: So my advice, if you are planning to buy any more orange trees, is to speak to a good supplier and seek out a nice mature tree with a thicker trunk rather than a spindly immature tree. I know a more mature tree is going to cost more, but I think it is worth it if you live in a cooler climate.
There are some varieties of orange trees that are cultivated to resistant cold temperatures, but all cultivars require protection from frost over Winter, so it is important to bring them indoors and place them in either a:
- Heated greenhouse
- Sunny South facing window (ideally 6 hours of direct sunlight)
- A porch or conservatory.
Ideally, choose a location that has the most sun so that the orange tree can still benefit from as much natural light as possible during Winter.
What I have found that works best for me is to place my tree in my glass porch (which sort of acts like a greenhouse). The porch at the front of my house stays a few degrees cooler than the rest of the house (because there is no indoor heating) but stays well above freezing, and my tree gets a lot of light.
Since I started moving my tree here for the winter, it has retained all its leaves, and it gets a good head start in the spring.
If the orange tree is losing leaves in Fall/Winter yet the temperature is still above 50°F (10°C) this is usually because of a reaction due to a sudden temperature fluctuation as the nights get cooler and there are fewer hours of sunlight.
The solution is to still bring the tree indoors (or use horticultural fleece if planted outdoors) and ideally find a nice sunny spot.
My orange trees that have lost some of their leaves recovered and regrew leaves in the Spring with warmer temperatures and more sunlight.
However, it should be noted that bringing orange trees indoors can also trigger more leaves to drop due to a sudden change in conditions or if you are not following the best practices of care…
Why is my Indoor Orange Tree Losing its Leaves?
If you have moved your orange tree indoors (or in a greenhouse) for Winter or recently bought one from a garden center, the orange tree often loses some, if not all, of its leaves due to the contrast in conditions from outdoors to an indoor environment.
This happened to me the first time I bought my orange and lemon trees.
Orange trees are carefully cultivated in commercial greenhouses before sale, which means they have acclimated to growing in very specific, optimal conditions and experience significant transplant stress if they are moved to a different environment.
All citrus plants are sensitive to a sudden variation in their environment and can lose their leaves because:
- Humidity. Houses in winter have much lower humidity due to indoor heating. My indoor heating used to dry out the air, which sapped moisture from their leaves, causing them to drop off. I discovered Orange trees grow best in 30% to 60% humidity.
- Temperature. A sudden difference in temperature can cause enough shock for the orange tree to drop its leaves. It is also worth noting that indoors, the temperature is often increased at night due to indoor heating, which is the opposite cycle of temperatures that orange trees experience outdoors, with cooler evenings and warmer days, which can contribute to the leaves dropping.
- Sunlight. Orange trees prefer full sun and can lose their leaves indoors with less light. (I place mine in a glass porch, but you need to place yours in the sunniest window you have to prevent the leaves from dropping.
- Air currents from forced air or air conditioning can also dry out the air to the extent that the orange tree drops its leaves to conserve moisture. This is a big problem for those of you who live in hot climates.
- Difference in watering. Typically, the rule is that orange trees also need to be watered less often in winter as they go dormant. However, from experience, I personally found that my orange tree was suffering due to increased heat and dry air. The soil can dry out and bake hard, causing water to run off the surface and down the side of the pot without infiltrating the soil properly and reaching the roots where it is required, causing the leaves to drop due to drought stress.
It is very common for an orange tree to drop its leaves when brought indoors, but this does not necessarily mean the tree is going to die, as it is usually just a reaction to the stress of being moved.
I found that there are several ways to mitigate the impact of this stress to ensure the orange tree survives despite losing its leaves. Here’s what I did…
How I Revived My Indoor Orange Tree That Lost Its Leaves
The way to revive an orange tree after the leaves have started dropping and to reduce any further leaf drop…
- In Winter, houses are particularly low in humidity compared to outdoors due to indoor heating, so I decreased the contrast in humidity by misting my orange tree every day to create a humid micro-climate. You can also buy a plant humidifier at garden centers and online which provides consistent humidity to prevent the orange tree’s losing too much moisture and dropping off. I have heard both methods can prevent leaves from dropping off and keep trees happy.
- Place the orange tree in the sunniest, south-facing window, porch, or balcony of the house or in a heated greenhouse if possible. The sudden decrease in daylight indoors is one of the main contributors to leaf drop. Your orange tree is going to have to have priority access to the sunniest room in your house if it is going to regrow leaves.
- It is important to maintain a consistent room temperature to prevent the orange tree from losing its leaves. Keep the tree away on the other side of the room from any source of indoor heat, such as radiators or fires, and out of the way of any air currents from forced air. Typically, orange trees can grow well with indoor temperatures as long as they are not next to the source of heat and the room is not cooler than 50°F (10°C) at night. My porch is perfect because it is unheated. However, if you have access to a heated greenhouse, I would consider moving your’s there.
- The orange tree has to contend with different temperatures, dry air currents, and low humidity when indoors, which can all increase water loss from the leaves, causing them to drop. This means you may have to increase the frequency of watering of the orange tree to avoid losing leaves.
- However, as I stated, this can be a balancing act as orange trees grow at a much slower rate in Winter due to fewer hours of sun and a lower light intensity, which means they require less water. Too much moisture around the roots in Winter can result in root rot, which also causes the leaves to turn yellow and drop off.
- The key is to water the soil with a good soak in Winter and then wait until the top 2 inches of the soil feel dry before watering again. This cycle of watering prevents the orange tree from drying out completely and mitigates the risk of root rot. I use my finger to tell when the soil is drying out as I have found this is a much more reliable way to tell when your tree needs watering compared with a moisture meter or simply waiting an arbitrary amount of time.
I can assure you that some leaf drops do naturally occur in Winter, even on orange trees that are grown commercially in optimal conditions, so don’t worry.
Even if all the leaves drop in Winter, as long as your orange tree is being cared for properly and has not died back due to frost, then citrus trees are surprisingly resilient, and the leaves can regrow in Spring.
As soon as the weather warms up and the night temperatures are consistently warmer than 50°F (10°C) place the potted orange tree outdoors or in a greenhouse so that it can benefit from more hours of sun which should stimulate new leaf growth.
My best tip: I also use a special citrus fertilizer as the process of growing new leaves is demanding and requires lots of nutrients. Citrus fertilizers are available from garden centers and provide all the nutrients that your orange tree needs at the right concentration. They also support fruiting, so it is well worth the investment.
Why Are My Orange Trees Losing Leaves in Summer?
From what I have learned, orange trees usually lose their leaves in summer due to drought or a lack of nutrients in the soil. Orange trees need consistently moist soil in Spring and Summer during active growth and (I have had the best results with) a citrus fertilizer. If the soil dries out of the soil is nutrient-poor, the orange tree leaves droop and drop off.
Orange trees are particularly nutrient-hungry in Spring and Summer when the leaves are growing and fruit is forming. If the orange tree is planted on nutrient-poor soil, then the leaves tend to curl, turn yellow, and drop off.
I have seen that orange trees planted in pots can exhaust the nutrients in the pot after a year or two, which can result in falling leaves in summer.
It is also worth noting that orange trees prefer to grow in full sun, so if any overhanging trees cast shade on the orange tree, this can be responsible for poor growth, lack of flowers or fruit, and fewer leaves in summer.
Overwatering and Drought…
Orange trees require a balance of well-draining soil that stays consistently moist during Spring and Summer.
Essentially, what this means is that the orange tree does not like to have its roots in boggy, saturated soil as this results in root rot and can cause the leaves to drop and die back.
Orange trees can suffer root rot because:
- They are planted in boggy low-lying areas of the garden.
- Pots without drainage holes in the base.
- The use of saucers, trays, or decorative outer pots prevents water from draining properly and causes water to pool around the orange tree roots.
- Watering too often.
However, if the orange tree is planted in sandy, quick-draining soil, the soil may drain too quickly for its roots to draw up the moisture they require, resulting in curling leaves that drop off.
This became a problem for me in summer, for my orange trees were planted in pots, and pots can dry out too quickly with blazing sunshine and scorching temperatures.
Smaller pots have less capacity for soil and, therefore, hold less moisture, so even if you are watering regularly, the soil can still dry out too quickly, and the orange tree’s leaves fall off due to drought.
Too much wind can also dry out the leaves and cause them to drop off, so plant the orange tree in a sheltered spot in the garden, or you can do as I did, which is to provide shelter with shrubbery as a wind break. My orange tree is sheltered by my bamboo plant, which provides an excellent buffer.
How I Revive Orange Trees Losing Leaves in Summer
- I use a citrus fertilizer in the Spring and Summer to prevent falling leaves. A specific citrus fertilizer provides all the nutrients the orange tree needs at the right concentration. This should provide enough nutrients to support the leaves and promote the development of oranges and the growth of the orange tree.
- Check to see if your orange tree roots are pot-bound. If the roots are pressed up against the sides of the pot, it is time to re-pot the orange tree to another pot one size up. I do this by scratching back the soil. A larger pot provides more soil and a greater capacity for retaining moisture, which should help the tree retain its leaves. I must emphasize that the best time to repot an orange tree is in the Spring, but repot in the Summer if the leaves are falling drastically. I would caution against repotting at any other time of year.
- I would cut back any overhanging trees or shrubs that may be casting shade on the orange tree. Orange trees need full sun, so moving them to a nice sunny area of the garden is necessary, which can help stimulate the growth of new leaves.
- Orange trees need a balance of around 2/3’s compost and 1/3 grit to retain moisture and avoid root rot. This soil mix has the right amount of compost to retain moisture to avoid drought and is also porous and well-draining due to the grit, which prevents root rot. I advise using grit rather than sand, as grit has a larger particle size, which ensures more efficient drainage. Mix the compost and the grit thoroughly before repotting your orange tree.
- Plant orange trees in pots with drainage holes in the base and use feet underneath the pots. I use bricks to elevate the orange tree’s pot off the ground to help promote good drainage. I prefer using bricks as I have seen pots that are placed directly onto patio slabs, which can sometimes prevent good drainage and cause the potting soil to stay damp for too long.
- Water orange trees when the first inch of soil feels dry. I must highlight that there is no universal advice that I or anyone else can give you for how often you water your orange tree, as this can depend on the temperature, maturity of the tree, size of the pot, etc. So the best way to do it is to feel the soil regularly with your finger to detect how long it takes for the top inch of the soil to feel somewhat dry, at which point give the orange tree a really good soak.
- Sometimes, the soil can bake hard due to blazing sunshine and high temperatures. This can cause water to run off the surface of the soil and down the side of the pot without infiltrating the soil properly and reaching the roots, resulting in falling leaves due to drought. If you scratch back the first layer of the soil, it can be very dry underneath despite watering. In this case, I use the hose pipe on my pot and soak it for a long time. I then lift the pot up, at which point I can assure you it feels significantly heavier, which tells me the soil has absorbed the water properly.
The best way to revive orange trees that are dropping leaves is to recreate the conditions of the orange tree’s preferred habitat with full sun, well-draining yet moist soil, use a citrus fertilizer, and protect the tree from temperatures cooler than 50°F (10°C).
From what I have learned, the orange tree can start to regrow its leaves as quickly as 3 weeks in the Spring and Summer in favorable conditions, but from my observations, it can take a lot longer to revive in the Fall and Winter.
Unfortunately, I can report the orange tree may not produce fruit this year if it has lost a lot of leaves and been under significant stress.
Orange trees that have lost their leaves due to waterlogged soil often do not recover because of root rot.
(If you think your orange tree is dying, read my article on how to revive a dying orange tree for the solution).
Key Takeaways:
- Orange trees lose their leaves because of overwatering, underwatering, poor soil, too much wind, or low temperatures. Orange trees do not tolerate temperatures lower than 50°F (10°C) and react to cold temperatures by dropping their leaves. Drought causes the leaves to curl up, turn yellow, and drop off.
- Indoor orange trees lose their leaves because of a sudden contrast in conditions due to indoor heating, lower humidity, or a lack of sunlight. Orange trees need full sun, consistent temperatures, and high humidity when indoors to retain their leaves.
- Orange trees lose their leaves in Summer because of drought, overwatering, and slow-draining soils. Orange trees need a balance of moist soil that is able to drain effectively. The leaves turn yellow and drop off if the soil is waterlogged or too dry.
- To save an orange tree from losing its leaves, recreate the preferred conditions of its Mediterranean with moist yet well-draining soil and full sun, shelter it from excess wind, apply a citrus fertilizer, and protect the tree from temperatures cooler than 50°F (10°C) and the leaves should regrow in the Spring.