Olive trees are my favorite Mediterranean plant to grow, but they can have a habit of losing their leaves if you do not emulate some of the growing conditions of the olive trees’ natural environment. But what are the most common reasons for olive tree leaf loss?
Olive trees lose their leaves due to overwatering, a lack of sunlight, and cold temperatures. Indoor olive tree leaves curl and drop off due to fluctuations in temperature and humidity and because they are in too much shade.
Olive trees are Mediterranean in origin and to prevent your olive tree from dropping leaves, replicate some of the growing conditions of their native environment with well-draining soil, full sun, and protection from freezing temperatures.
Do not worry as I have saved my own olive tree which had bear branches and I share all my experience in this article…
Keep reading to learn why your olive tree is losing its leaves, whether it’s indoors, in Winter, after repotting, or for any other reason, and learn how you can implement the solutions to save your Olive tree from leaf drop…
Why is My Olive Tree Losing Leaves in Winter?
Olive trees are well adapted to hot and relatively dry Mediterranean climates that have mild Winters, usually without freezing temperatures.
If you live in a climate where temperatures reach freezing in Winter (as I do), then I recommend growing olive trees in pots and giving them some form of protection in Winter.
Olive trees do become more tolerant of cold temperatures as they mature. What I have learned from growers in the Mediterranean is that with thicker trunks, the older gnarled olive trees tend to be more cold-hardy than the skinny trucked immature trees, so my advice if you buy a new olive tree is to go with a bigger, more mature specimen.
I personally bought my first olive trees that were skinny young trees, which is a decision I regret because they lost their leaves in the cold.
The leaves of olive trees often drop in Winter to some extent (particularly if they are in climates that significantly contrast the Mediterranean) due to cooler temperatures, fewer hours of light, and lower light intensity. However, I think you all olive trees should be protected to reduce the number of leaves dropping as the olive can die in particularly adverse conditions.
Ideally move the olive tree to a heated greenhouse (If you are lucky enough to have a heated greenhouse!) as this has the benefit of a higher average temperature as well as far more hours of sunlight (olive trees need full sun). You can also place the olive tree in a cool porch or as I did, place mine in my conservatory that preferabely has a South facing aspect for a much light as possible.
It is particularly important to keep the roots insulated (as they are the most cold-vulnerable part of the tree), so use some horticultural fleece or bubble wrap around the pot to keep the cold out.
From experience, I can say it doesn’t necessarily have to reach freezing for the leaves to drop off the olive tree. If the temperature suddenly decreases, this sudden contrast is likely to trigger the leaves to drop.
If all the leaves have dropped off due to cold temperatures, then protect your olive tree from freezing temperatures for the rest of the Winter and locate it in a sunny location. When I protected my trees from the worst of the Winter temperatures, far fewer leaves fell off, and it gave my tree a head start in growing new leaves in the following Spring.
Why is My Indoor Olive Tree Losing Leaves?
If you have recently brought your olive tree indoors to protect it in Winter or recently bought one from a garden center, then I find the olive tree often loses some, if not all, of its leaves due to the contrast in conditions between the outdoors and the indoor environment.
As explained to me by commercial growers, olive trees are often cultivated in very specific, controlled conditions before sale in a commercial greenhouse, and when they are moved, the transplant stress often causes dropping leaves.
Olive trees are sensitive to sudden variation in environmental conditions and can start to curl and then drop their leaves indoors due to:
- Sunlight. Olive trees are native to warm climates with full sun, so there are often too few hours of light indoors for the olive tree to support its leaves and grow.
- Temperatures. Olive trees are not cold hardy, so when they are moved inside, there is often a significant contrast in temperatures, which causes the plant shock and results in dropping leaves. Indoor heating can also cause the temperature to increase at night, whereas the olive tree is adapted to cooler temperatures in the evening, which also contributes to falling leaves.
- Humidity. Houses in Winter (or at any time of the year) often have much lower levels of humidity than outdoors, which can sap too much moisture from the leaves, causing them to curl up and drop off.
- Airflow from air conditioning, forced air, or convection currents from other sources of indoor heating saps moisture from the leaves of the olive tree, causing them to drop to conserve water.
- Differences in the watering frequency or rainfall can also cause stress and contribute to leaves dropping indoors.
It is very common for olive trees to drop their leaves when they are brought indoors, so don’t worry, you are not alone but; this does not mean the tree is going to die; it is just a reaction to the fluctuating conditions indoors, and there are ways to mitigate the impact of the stress so that the olive tree survives after dropping its leaves indoors…
How to Save Indoor Olive Trees…
Here are my best tips to revive the olive tree after losing its leaves and to mitigate any further leaf drop…
- Houses in Winter are particularly low in humidity, so I recommend occasionally misting the olive tree (once every 2 days) to counteract the dry air indoors. This should help prevent the leaves from curling and dropping off.
- Always locate your olive tree in the sunniest window of the house. Bright light is typically not enough for olive trees as they are adapted to growing in open, sunny areas, so try to find an area with as much direct sunlight as possible. This should give them more energy for photosynthesis and help retain any leaves.
- Try to maintain a fairly consistent temperature range, as I find sudden fluctuations are a major cause of falling leaves. The biggest mistake I see is keeping olive trees near radiators or any other sources of heat, as this can dry out the soil too quickly and sap moisture from the leaves.
- Avoid locating your olive tree in the path of any air currents from air conditioning or forced air.
- Higher indoor temperatures, dry air currents, low humidity, and a lack of natural rainfall all cause more water loss from the olive tree than it would typically experience outdoors, which means you may have to increase the frequency of watering to avoid the olive tree losing its leaves due to drought stress. However, this is a balancing act, as overwatering can also be responsible for falling leaves. Give the olive tree a good soak in the Spring and Summer once a week, and scale back the watering to once every 4 weeks in Winter. If the leaves start to curl before dropping, increase the frequency of watering and the humidity by misting the leaves.
If your olive tree has lost all of its leaves indoors, I assure you it can still recover as long as you address any environmental concerns (such as low light or low humidity), and the olive tree should be able to grow leaves when the conditions are more favorable in the growing season in the Spring and Summer.
I know it can be a frustrating game of patience but I promise it is worth it!
Overwatering and Slow Drainage Causes Olive Trees to Drop Leaves
As I previously stated, olive trees are native to the Mediterranean region of Europe, where they grow best on rocky slopes in well-draining soil of low to medium fertility with high temperatures and relatively low rainfall.
These conditions ensure that the soil around the roots is aerated, porous, and drains efficiently to avoid water logging.
If the olive tree has too much moisture around the roots, then this is contrary to their natural preferred conditions and can interfere with root respiration and promote the conditions for root rot.
The most common reasons for too much moisture around the roots that I encounter are:
- Overwatering.
- Slow-draining soils.
- Pots without drainage holes in their base.
- The use of any saucers or trays underneath the pot causes water to pool around the base.
Heavy clay soil or even unamended potting soil can all retain too much moisture for too long after watering for the olive tree to tolerate, which causes the leaves to turn yellow or brown and drop off.
How to Save an Overwatered Olive Tree that is Dropping Leaves
Whilst you do not need a Mediterranean climate to grow olive trees, it is important to replicate aspects of the native environment to create favorable drainage soil conditions.
- The most important factor is to scale back the frequency of watering. Olive trees need the soil to be relatively dry between each bout of watering or rainfall. I recommend watering potted olive trees about once per week in the Summer and only watering every 2 weeks in the Spring if there has been no significant rainfall. You only need to water olive trees in Winter (about once every 4 weeks or so) if they are indoors. How often you water, of course, depends on your climate, with potted olive trees in arid climates needing more frequent watering and olive trees in more rainy, overcast climates needing less water, so adjust your schedule accordingly.
- Olive trees need well-draining soil that replicates the soil conditions in their natural environment. If the soil is too rich and retains too much water, then this has the same effect as overwatering and results in falling leaves and possibly root rot.
- I personally use a potting mix of about 50% potting soil amended with 25% horticultural grit and 25% horticultural sand (by volume of the pot). This creates the optimal well-draining soil structure. The different-sized particles composed of sand and grit are very effective at mimicking the drainage conditions of the olive tree’s rocky environments creating excellent drainage.
Good soil drainage helps to counteract overwatering and high rainfall to ensure the olive tree’s roots remain healthy.
- I love to place my olive tree’s pot on ‘feet’, which elevate the pot an inch or so off the ground. This helps to further promote drainage, which is particularly important in climates that have higher levels of rainfall than the Mediterranean.
- Ensure that pots have a drainage hole in the base; if not, repot your olive tree to prevent root rot.
If your olive tree is planted in normal potting soil, then I recommend repotting as soon as possible, regardless of the time of year, as if it remains in damp soil, it is likely to die of root rot.
Once you scale back the watering and improve the drainage conditions, the olive tree should be less stressed.
Even if it has lost its leaves, I can tell you from my experience that olive trees are surprisingly resilient, and the leaves can regrow (in the Spring and Summer) when growing conditions are more favorable.
Losing Leaves Due to a Lack of Water
Whilst it is more common for olive trees to lose their leaves due to overwatering, in rare cases, I have seen them lose leaves if the root ball dries out completely and bakes hard in the sun.
If the olive tree leaves shrivel or curl before dropping, then this would typically indicate that your olive tree is suffering drought stress.
The leaves curl to reduce their surface area which helps to conserve moisture. The leaves drop off in extreme drought as a survival strategy to prevent further water loss.
Your olive trees can lose their leaves from drought stress because of:
- The pot is too small and, therefore, is unable to accommodate the olive tree’s extensive root system. One of the olive tree’s key adaptions to drought is that the roots are deep and able to access moisture deep underground. If the pot is too small, then it has less capacity for soil and therefore dries out much quicker. This is often exacerbated by the fact that olive trees need full sun which causes the olive tree’s pot to heat up quickly and bake hard, depriving the olive tree of moisture, and the soil can be hard and difficult for the roots to grow.
- Watering too lightly. Olive trees do not need to be watered as often as a lot of plants due to their resistance to drought, but they do require a good soak. If the soil is watered too lightly, then the moisture does not infiltrate the soil and reach the roots where it is required.
- Keep in mind that a lot of olive trees (that I see in garden centers) have dark, fashionable pots that can absorb extra heat from the soil and dry out the soil too quickly.
- Excess heat from Summer heat waves and low rainfall can also cause some leaves to drop.
How to Save it…
Olive trees that have lost their leaves due to a lack of water often recover due to their resilience to drought.
After a period of drought, it is important to soak the olive tree’s root ball as effectively as possible.
When the soil dries out completely, it can bake hard and repel water off the surface, causing the water to run down the side of the pot without reaching the roots.
Therefore, it is essential to soak the entire pot and even submerge it (if possible) for 10 minutes or so; however, I realise doing this can be tricky.
The way I did this with my olive tree is by entirely submerging my pot of the olive tree in a wheel barrow full of water for around 10 minutes or so, then the moisture can infiltrate the soil effectively and the olive tree can get the drink it requires to help it recover.
If this is not practical (due to the weight of the tree and pot), then water the olive tree as generously as you can and scratch back the surface of the soil to assess whether the water is infiltrating properly.
In this case, I would recommend buying a moisture meter which is a good way to detect whether the water is soaking into the soil properly.
Once the soil has been thoroughly soaked, the structure changes, and it should not repel water in the same way as long as you don’t leave it too long between bouts of watering.
Top tip: All the commercial growers told me that a good way to prevent this from happening is when you come to re-pot your olive tree, use a more porous potting mix of 50% potting soil, 25% horticultural grit, and 25% horticultural sand to create the open porous structure that allows water to easily infiltrate even when it has been baked in the sun.
This process allows the olive tree to recover from drought stress, and as long as you adjust your watering schedule to prevent the soil from baking in the sun, then the leaves should regrow in the Spring and Summer.
Losing Leaves Due to a Lack of Sunlight…
Olive trees can drop their leaves if they are in too much shade.
Olive trees have specifically adapted to growing in open areas in full sun in their native Mediterranean habitat, so if they are in the shade, the leaves can turn yellow and fall off, with poor overall growth of the tree, so do not locate your olive trees in the shade.
Always locate your olive tree in as much sun as possible, whether that is out in the garden, greenhouse, or in a south-facing window indoors.
It is particularly important to locate olive trees in South facing, sunny windows when bringing the olive tree indoors for Winter protection as there are fewer hours of sun and lower intensity of light in Winter so the olive tree requires as much sun as possible to stay healthy and prevent leaf drop. My porch is South facing, so it works well for storing my olive tree in Winter.
Lack Of Fertilizer can Contribute to Leaves Dropping
Olive trees are not especially heavy feeders as they are adapted to growing in rocky soils that do not necessarily retain a lot of nutrients.
However, if they have been in the same pot for several years, then the olive tree’s extensive root system can exhaust the potting soil of available nutrients, which can reduce the rate of growth and cause the leaves to turn yellow or brown and fall off.
As olive trees are specifically adapted to growing in specific conditions in the Mediterranean, it is important to use an olive tree fertilizer (instead of an all-purpose fertilizer), which provides the olive tree with the right nutrients at the optimal concentration.
When my olive tree lost its leaves, this is the fertilizer that I used to help it rejuvenate. I found that the growth of new leaves can be a bit sluggish without fertilizer as growing all new leaves is such an energy intensive process.
I applied the fertilizer once a month in the Spring until about mid summer, and my olive tree looked much better for it.
Why is My Olive Tree Losing Leaves After Repotting?
Olive trees often lose some of their leaves after repotting due to stress. This is very common, and the leaves grow back in the Spring and Summer as long as the growing conditions are favorable such as:
- Locating the olive tree in full sun.
- Watering when the soil has a chance to dry out ( to prevent root rot).
- Protecting the olive tree from freezing temperatures.
- Repotting the olive tree into a pot that is only slightly larger than the previous pot.
- Repotting the olive tree in potting soil that is amended with horticultural grit and sand for improved drainage.
Believe me, if you ask any olive grower in Greece, they will tell you that Spring is always the best time to repot your olive trees as this is the time of year when they are most resilient.
Something that you should bear in mind is that larger pots have a greater capacity for soil and, therefore, a greater capacity for moisture. If you repot your olive tree into a pot that is too large, then the soil is likely to take too long to dry out, which promotes the conditions for root rot and causes the leaves to drop, so always choose a pot that is only slightly larger than the previous pot.
I personally make sure my new pot is only 2 inches or so larger in diameter than the previous pot for this reason.
Remember that olive roots like to grow deep more so than outward, so when choosing your pot select a deeper pot rather than just a wider pot.
If you do not have a deep enough pot, I would recommend looking online, as this is an important step to save your tree.
A classic mistake that I see people make when repotting their olive tree is firming the potting soil. Avoid firming in the potting soil too much, as this pushes out the oxygen from the soil, which interferes with root respiration.
My love tree recovered from repotting (with the help of the fertilizer that I previously mentioned) in the early Spring, with new leaves emerging in around March. I think the new leaves would grow without the fertilizer, but your tree is likely to look a bit sparse. However, 2 years after my olive tree lost its leaves, mine is not looking great!
(Read my article, how to revive a dying olive tree).
Key Takeaways:
- Olive trees lose their leaves as a reaction to cold temperatures, overwatering, a lack of sunlight, and because of a contrast in growing conditions when they are brought indoors for Winter protection.
- To revive olive trees that are losing leaves it is essential to protect them from the cold, locate them in full sun, and only water when the soil has dried.
- Olive trees can regrow their leaves when you recreate the conditions of their native environment with more sunlight, gritty well-draining soils, and mild temperatures in Winter.
- Indoor olive tree leaves can curl before falling off in dry homes due to the lack of humidity, fluctuating temperatures, and lack of sunlight. Locate the olive tree in a sunny south-facing Window, mist the leaves, and keep it away from any direct sources of heat, and the leaves should regrow in the Spring.