The Japanese aralia is one of the popular ornamental shrubs that are considered hard to kill. Also known as Fatsia japonica, this tough evergreen is highly praised for its exotic foliage, making it a common favorite for indoor landscapes.
Unfortunately, unfavorable growing conditions and a lack of proper care can leave your Japanese aralia vulnerable to several issues. In this guide, we have listed the most common problems you might face as you grow and propagate this amazing plant.
1. Sunburn caused by direct sunlight exposure
Although the Japanese aralia is widely grown and propagated throughout the world, this evergreen shrub does best in areas with subtropical climates. This implies that aralias grow best under a shade where they can get bright, diffused light. Leaving them exposed to the scorching heat of the sun can burn their leaves!
Unfortunately, leaf scorch is a fairly common problem in Japanese aralias, simply due to growers’ ignorance. Even an indoor setting can put your plant at risk of sunburn if it is placed too near an open window with full sunlight.
Thankfully, sunburn issues can be quickly resolved simply by moving your plant to a shadier location. The Japanese aralia is tolerant of low to medium light, which makes it ideal for your indoor spaces.
2. Brown and crispy leaves due to underwatering
When was the last time you watered your plants?
If you are guilty of neglecting your houseplants for long periods, you are certainly not alone! Underwatering is a common mistake among growers – especially those who have busy schedules. Nevertheless, even hardy plants like aralias need a degree of pampering to maintain their lush, green appearance.
Timely watering is key to avoiding underwatering issues. The rule of thumb is this: water your plant only when the top layer of soil feels dry. Use your finger to check the soil’s moisture level, or use a soil moisture meter if you prefer a more accurate reading.
Keep in mind that there are also other contributing factors that can cause the browning of Japanese aralia leaves. For example, a lack of humidity can dry the leaves and cause browning. Hard water can also be harsh on your Japanese aralia due to its toxic mineral content. Switch to rainwater or filtered tap water if you notice your plant’s leaves turning brown and crisp!
3. Overfertilization issues
Although Japanese aralias love nutrient-rich soil, giving them too much fertilizer can do more harm than good!
While aralias are fast-growing species, they do not necessarily need large doses of fertilizer to thrive. This leaves some novice growers overestimating the needs of their plants! The excess nutrients will not be absorbed by the plant and will instead end up as a salt buildup in the soil. This is why you see white crusts on the soil if you regularly overfeed your plants.
The end result of overfertilization is root burn. Japanese aralias struggling with root burn will have brown leaf margins and a sad-looking appearance. In the long run, the root damage can stunt your plant’s growth.
4. Root rot due to waterlogged soil
Root rot is a common yet dangerous disease prevalent among indoor plants. It attacks the roots of your Japanese aralia if you allow your plant to grow in an overly damp medium for too long. As with any plant, decaying roots can cut your aralia’s life short if you do not act right away.
The common causes of root rot are:
- Using pots that have poor drainage
- Using pots that are too deep or too large for your plant
- Using a compact or dense medium such as ordinary garden soil or clay soil
- Keeping the soil and leaves wet for too long which encourages the growth of bacteria and fungi
To prevent root rot and fungal diseases, the best approach is to adhere to a correct watering routine. As mentioned, water your plants only when the top layer of soil is dry, and make sure you use the correct pots and a breathable soil mix to maintain healthy roots.
5. Rootbound Issues
Do you know that Japanese aralias can grow up to 18 inches per season? These hardy, ornamental plants can easily reach a height of six feet if grown indoors under favorable conditions!
This means that your fast-growing aralia can quickly outgrow its initial pot, leaving it rootbound. As the root ball becomes too dense for the space inside the pot, the growth and overall appearance of your plant will be compromised.
These are some of the tell-tale signs of a root-bound Japanese aralia:
- Roots growing out from the pot’s drainage holes
- Wilting and drooping
- Cracked or damaged pot caused by compacted roots
- Soil displacement in the pot
- Yellow leaves
To revive your plant, simply repot it in a slightly bigger container. The rule for choosing the right pot size is straightforward: the diameter of the pot should be about two inches wider than the root ball. You can also prune your Japanese aralia and propagate the cut stems in smaller pots. This way, you can easily control the size of your plant.
6. Pest infestations
Pests like spider mites can cause great damage to the leaves of your Japanese aralia. These tiny bugs take up residence on the plant’s foliage and feed on the sap, or leaf juice, compromising the overall health of the plant.
If you notice white or silvery substances or web-like structures on the plant’s leaves, this is a clear sign of infestation and you need to act immediately to stop it!
Here are some tips to get rid of the pests:
- Prune the damaged leaves and stems using a clean pair of scissors or pruning shears.
- Dilute neem oil in water and spray the mixture directly on the leaves and stems. Reapply every three to four days until all the pests are gone.
- You can also use insecticidal soaps to eradicate the sap-sucking bugs. Make sure to follow the instructions on the packaging before treating your plants.
7. Stunted growth
Stunted growth is another issue sometimes encountered by Japanese aralia growers. This phenomenon is generally caused by environmental stressors or inappropriate growing media.
If you suspect that your aralia’s growth is unusually slow, make sure to follow these tips to correct any underlying issues:
- Avoid moving your plant too frequently. Most indoor plants like Japanese aralias are quite sensitive to new environments.
- Use the correct soil mix for your plants. Although aralias do not make a lot of fuss when it comes to soil type, they are best grown in slightly moist and well-draining soils.
- Make sure your plant receives the basic care requirements – correct watering, proper humidity levels, indirect sunlight, and the correct fertilizer dosage.
8. Yellow leaves caused by plant stress
Japanese aralias can get stressed, too! Just like humans, your plants go through a series of physiological changes in response to external stressors such as transplanting, sudden temperature changes, drought, and many others. Under these stressful conditions, your Japanese aralia can be more vulnerable to pest infestations and diseases.
Curling leaves is an early sign of a plant experiencing some form of stress. The other symptoms might become more noticeable later on, as the underlying issue progresses.
But do not worry – your Japanese aralia is a hardy plant! Correcting the issue right away should ensure that it recovers quickly and completely.
9. Fungal diseases
Fungal infections can be quite common in Japanese aralias, especially since these tropical shrubs enjoy growing in moist air and soil. Unfortunately, bacteria and fungi also love humid environments, and will attack your plants if you are not keeping a watchful eye and maintaining the correct care.
Common fungal diseases in aralias generally manifest as blotchy or dotted clumps on the leaves, necrotic lesions on the leaves, moldy soil, and mushy-looking roots that smell like a swamp.
An appropriate fungicide should help your Japanese aralia recover from such infection. If the disease has become severe, it might be more challenging to save your plant, so remember that prevention is always better than cure and never overwater your plants!
10. Yellow leaves caused by alkaline soil
The Japanese aralia prefers neutral or mildly acidic, nutrient-rich soil. If you are growing your plant in alkaline soil, it will likely result in curled and yellowed leaves. The symptoms are similar to those of a nutrient deficiency, because soil alkalinity inhibits the proper absorption of nutrients by the roots.
Alkaline soil also tends to hold excess amounts of calcium, magnesium, and sodium, which makes the soil less soluble. It is also for this reason that you should avoid using hard water for your indoor plants.
Checking the soil’s pH should be your first step when growing a Japanese aralia. You can purchase soil pH strips to ensure that your growing medium is ideal for your plants. Soil pH meters like SONKIR also do a great job if you want more reliable and accurate readings.
11. Uneven growth due to lack of light
Sparse, uneven growth is a classic sign of a Japanese aralia that is not receiving enough light. You might also notice the plant producing smaller leaves over time as a result of long-term light deprivation.
As with all plants, your Japanese aralia needs sufficient and correct lighting to conduct photosynthesis – exposure to medium, indirect sunlight is ideal for this plant. Hence, placing your aralia near an east-facing window or another spot that gets diffused sunlight should help correct any light-related problems. Rotate your plant slightly from time to time if you think one side is getting significantly more light than the other.
Despite its hardiness and neglect-tolerant reputation, the Japanese aralia is not completely immune to common plant issues. Without proper care, your plant can suffer from irreversible damage which might lead to its early demise if you do not intervene quickly enough! Hopefully, this list of common Japanese aralia problems will serve as a useful guide to help you avoid such issues in the future.