If your plant is in a pot, ensure there are drainage holes so excess water can flush out. Lastly, cut back on watering (not just for your Umbrella Plants, but all plants) in the cold weather. During lower temperatures, give the plant just enough water to prevent it from completely drying out.
Inadequate Lighting
If the leaf drop in your Umbrella Plant is also accompanied by spindly new growth, it’s a sign that it’s not getting enough light. If you have a variegated Schefflera species, another sign of low lighting can be the leaves losing their color(s) and turning uniformly green.
Umbrella Plants grow best in bright indirect lighting. Make sure yours gets enough of it to grow healthy. Protect your plant from intense direct rays as they can cause scorching on leaves. Morning and late afternoon light are best for Scheffleras. If growing outdoors, make sure to provide midday shade.
Heavy Soil
Umbrella Plants grow best in well-draining soil with plenty of aeration. The soil should preserve oxygen around the roots even immediately after watering. If it doesn’t, it can contribute to stress and leaf loss. While a good quality potting mix would do, mixing it with cactus soil is a better option. You may also consider adding coarse sand or perlite to the potting mix to improve the aeration. Whatever you do, just don’t let your Schefflera sit in compact soil for too long. Ensure proper drainage, avoid partial watering, and give the soil a heavy watering once a month or two during the growing season to flush out toxins and mineral build-up from the soil.
Excessive Fertilizing
Umbrella Plants are light feeders. Frequent fertilization is a surefire way to stress the plant and trigger leaf loss.
If your Schefflera otherwise looks healthy and there are no apparent reasons for why it may be dropping leaves, overfertilization is most likely the cause. A quick fix for an overfertilized Umbrella Plant is to drain the soil. Give your plant a good soak and let the water flush out the fertilizer from the soil. If this doesn’t work, you should repot the plant in fresh soil.
It’s important to note here that Schefflera plants might also sometimes experience leaf loss due to under fertilization. However, the signs of leaf loss from inadequate fertilization are slightly different. An undernourished Umbrella Plant also exhibits minimal, lighter, and smaller new growth in addition to leaf loss.
To prevent overfeeding or underfertilizing your Schefflera, treat it with a half-diluted balanced fertilizer once a month only in the growing season. Do not fertilize the plant in fall and winter.
Lack of Humidity
Schefflera plants can handle a bit of dry air, but continued exposure to low humid conditions can stress the plant and contribute to leaf loss. If your plant is already stressed, dry air can make it worse. Fortunately, though, the issue is easy to fix.
If you’re growing Schefflera as a houseplant, use a humidifier. If it’s outdoor, place it close to other plants. You can also place water trays near your Umbrella Plant or a tray filled with water and pebbles underneath it (indoors and outdoors) to raise humidity levels.
Cold Temperature
Scheffleras are tropical plants. They aren’t acclimatized to cold weather. Low temperatures can cause the plant to go into stress, eventually leading to leaf loss. These plants thrive in temperatures between 60o and 80o Fahrenheit. While they can tolerate slightly lower temperatures, anything less than 50o Fahrenheit is sure to stress the plant.
Bring your outdoor Umbrella Plants indoors before the cold spell starts, and move indoor plants a little away from the windows where they can be exposed to cold air to prevent temperature-related stress and leaf drop.
While all Schefflera plants are sensitive to cold, green leaf species have a little higher tolerance to low temperatures than the variegated cultivars.
Exposure to Drafts
If you live in a windy place or your plant is in a location where it’s exposed to drafts, it can be the reason why your Umbrella Plant is losing leaves.
Scheffleras are averse to drafts, especially the cold ones, and shed leaves when exposed to them. So, make sure to protect them from strong winds and drafts. Provide protection or place them near something that breaks the airflow.
Repotting
If you’ve recently repotted your Schefflera and its dropping leaves now, it is the cause. Repotting is a little traumatic for plants, and shedding a few leaves after it is pretty normal. As long as you’re only repotting your Schefflera when needed, there is nothing to worry about. The leaf drop issue will resolve on its own after a little while.
To avoid overstressing your Umbrella Plant after repotting, repot at the beginning of the growing season so the plant can have ample time to recover and do not fertilize for a few weeks after repotting. The roots are tender when a plant is repotted. Fertilizing at that time or soon after can burn the roots. Moreover, fresh soil typically has enough nutrition and doesn’t need to be fertilized.
Do not repot a plant that you have just bought. Give it time to adjust to the new environment.
Not Repotting
While it’s not very common for Scheffleras to drop leaves for being in small containers, it’s not unheard of either. Umbrella Plants can do well in small containers and do not mind being slightly rootbound, but they may start dropping leaves if it gets severely rootbound. So, it’s best to keep an eye out and make sure the pot is the right size for your Schefflera plant.
Change in Environment
Like humans, plants acclimate to their environment and can get stressed when moved to new locations. One common reaction to this is the dropping of leaves. This is most common in newly bought plants; however, it can also occur if you change your plant’s location too often. Your Schefflera can also start dropping leaves when brought indoors for winter.
The good news is that this leaf loss is temporary and usually resolves on its own once the plant acclimates to the new environment. You just have to give it enough time to acclimate and avoid moving it around your home too often.
Pest Infestations
Though Scheffleras are quite resistant to pests, they are not completely immune to them. Pests can weaken your plant and trigger stress leading to leaf loss. Umbrella Plants can attract a variety of juice-sucking pests, but the insects that most commonly colonize these plants, especially in dry conditions, are the spider mites.
Spider mites thrive in dry conditions and most commonly hide on the undersides of the leaves, so they may not always be easily visible. If your Schefflera is dropping leaves for no apparent reason, it’s worth checking for spider mites and cleaning leaves as a proactive measure. If there is an infestation, removing the affected leaves is best before treating the plant with an insecticide and/or horticultural oil.
If you mist your Umbrella Plant regularly, it may also develop leaf blight and fungal issues. Check for them, too, and prune infected leaves if any of these issues are present.
Dropping Leaves Aren’t Always a Sign of a Problem
It’s common for plants to drop old leaves as they grow to make space for new leaves. So, dropping leaves isn’t always a sign of a problem. It could simply mean that your Schefflera plant is growing.
Having said that, it’s important to ensure proper care and keep an eye out for various issues. It’s not uncommon for Umbrella Plants to go into stress and drop leaves due to improper or poor growing conditions and care. Therefore, you should always investigate and find out what’s causing leaf loss in your Umbrella Plant. When your plant starts dropping leaves, look for all the potential causes. If you find any, fix it immediately. If there isn’t any, your plant is most likely in a growth phase.