Calibrachoa is a genus of flowering plants native to South America. These trailing, tender perennials are also known by several other nicknames, such as million bells, super bells, and trailing petunia. Calibrachoas are popular for their funnel-shaped flowers that come in many different shades, including lavender, burgundy, orange, pink, yellow, purple, coral, red, and cream.
What most gardeners love about these beauties, aside from their generous variety of colors, is their speed of growth and their adaptability to varying environmental conditions. Despite these advantages, however, growing a calibrachoa in your own backyard does not imply zero problems. At some point, you might notice their foliage starting to brown and die back, or they may stop producing any flowers.
These issues will naturally leave you scratching your head and wondering why your calibrachoa is dying. Read on to learn about the possible underlying issues and how to combat them right away.
Why is my calibrachoa dying? Common culprits
1. Fertilizer issues
Fertilizers are essential for a plant’s vigorous growth, whether they are applied in the form of organic matter or synthetic versions. They provide your plants – especially those grown in containers – with the complete range of essential macro- and micronutrients.
As much as we want to pamper our beautiful calibrachoa flowers with the ideal nutrients, we also need to remember that too much of a good thing is not always good – even for our houseplants. Overfertilization can cause an accumulation of salt in the soil, which can burn the roots. And, without healthy roots, a plant’s water and nutrient uptake is compromised, causing the leaves to brown and die.
If too much fertilizer is bad, skipping it completely can also slow the growth of your plants, especially if you are using soil of a poor quality. Nutrient deficiency can leave your plants vulnerable to pests and diseases, so to avoid such issues, you need to make sure that they are getting adequate nutrition. The added nutrients from fertilizers and organic compost will help boost flower production and encourage bushier growth of foliage.
2. Lack of sunlight
Calibrachoas need lots of sunshine to grow to their full potential. These evergreens like four to eight hours of full sunlight per day. If these conditions are not met, your plants will not be able to carry on their metabolic processes adequately, and this will result in wilting and dying leaves.
If you think a lack of light is the culprit behind your dying plant, the simple solution is to move it to an area that gets more sunlight. Your calibrachoa will appreciate an area or window that faces east, west, or south.
3. Fungal leaf spot
If you notice unusual brown spots on the leaves of your calibrachoa, then it is likely infected with leaf spot disease. You might also notice these spots growing larger over time, forming necrotic lesions on the affected leaves.
But what causes leaf spot disease? And how can you protect your calibrachoa from fungal infection?
The fungal spores that cause leaf spots thrive in warm, humid environments. These pathogens cling onto wet leaf surfaces and reproduce quickly, causing great damage to the foliage.
So how do you treat fungal leaf spot in your calibrachoa? Pruning and applying fungicides are generally the best solutions to control such infections.
First, trim and destroy the infected leaves. Also pick up any fallen leaves from the ground and burn them. This will prevent any spores from spreading into the ground and infecting other healthy plants.
Once the damaged plant parts are removed, you can then apply fungicide or neem oil to the remaining leaves. During the treatment period, make sure that the infected calibrachoa is isolated from your other plants.
4. Root rot disease
Root rot is a serious yet common plant disease that can also affect your calibrachoa. Plants affected with root rot will develop mushy, deteriorating roots that release a foul odor.
Soil-borne fungi such as Fusarium spp., Pythium spp., Rhizoctonia solani, and Phytophthora spp. can cause fungal root rot disease in most plants. Since these pathogens thrive in wet environments, root rot commonly affects plants that have been sitting too long in waterlogged soil. Some signs of root rot include browning and wilting leaves, branch dieback, new leaves that look paler and smaller, stunted growth, and significant leaf drop.
Unfortunately, root rot is an underground issue, which makes it challenging to diagnose without digging up the whole plant.
The disease can be triggered in many ways – the cause can be one or a combination of the following factors:
- Overwatering: While plants like calibrachoas need moist soil to thrive, giving them excessive amounts of water can drown the roots and attract fungal pathogens. Calibrachoas prefer the soak-and-dry method of watering, so giving them a drink once a week is usually enough to keep them healthy.
- Poor drainage: Using compacted or clay-like soil with poor drainage can have detrimental effects on your calibrachoas as these soils tend to retain too much water. The same is true for pots without drainage holes. If you are using soil and pots without adequate drainage, your calibrachoas will manifest the same symptoms as if they were overwatered.
- Using a drip tray or saucer: Drip trays and saucers are generally discouraged as they can prevent excess water from draining out of the bottom of the pot. As mentioned, the goal is to make the soil moist, but not watery, and using trays or saucers can potentially defeat the purpose of the pot’s drainage holes.
How to save your calibrachoa from root rot
If you suspect that your calibrachoa is struggling with root rot disease, the first thing you need to do is to check its roots. Gently lift the plant from its pot and closely assess the severity of the damage.
If most of the roots are still firm and white, then it is probably possible to revive your calibrachoa. First, prune any decaying roots that look dark or mushy, as well as any leaves and branches that have turned brown. Leave the healthy-looking parts attached to the plant.
The next step is to clean the remaining roots under running water to remove the infected soil and debris. Discard the old soil along with the pruned plant parts. Do not forget to thoroughly wash and disinfect your gardening tools once you are done.
Lastly, transfer your plant to fresh, well-draining soil. To avoid root rot in the future, make sure that your pots have drainage holes. It is also highly recommended to use a potting mix that contains peat moss and other organic materials, as this will improve the soil’s aeration and prevent compaction.
How often should I water my calibrachoa?
For optimal growth, a fully-established calibrachoa should be watered thoroughly once a week, while seedlings should be watered every other day. Also check the soil daily – it must be allowed to dry completely (but not become bone dry) before your next watering.
Common pests that attack calibrachoa
The leaves of your calibrachoa are also a favorite among certain destructive pests, including thrips, aphids, and mites. These tiny insects suck the nutrients from plant tissue and cause irreversible damage to the foliage. Severely infested calibrachoas will have leaf holes, leaf discolorations, and leaf distortions. These plants will eventually lose their vigor and die.
Thus, it is important to check the leaves regularly for any visible insect activity. You can also use organic pesticides like neem oil as a preventative care strategy or as a treatment.
What causes a calibrachoa to stop blooming?
If your calibrachoa fails to bloom, it does not necessarily mean it is dying. Often, this has something to do with too much nitrogen in the soil. Nitrogen is a macronutrient essential for foliage growth; however, high amounts of nitrogen will not be beneficial for flower production.
To promote blooming, the fertilizer ratio must be 20-10-20. For the best results, make sure to use a slow-release formula to allow continuous feeding of your plants.
Ways to revive a dying calibrachoa
There are several steps you need to take if you want to nurture your calibrachoa back to health. Generally, gardeners are more successful at saving a dying plant if the intervention is early. So, make sure to act quickly if you notice any unusual symptoms or changes in your plant’s foliage.
First, you need to understand the reason your plants are suddenly dying. Could it be overwatering? A fungal disease? Get to the bottom of this so you can identify the most effective solution to combat the issue.
Next, apply the solutions mentioned in this guide. For example, if the issue is caused by root rot disease, you will need to prune back the damaged stems and roots and apply the appropriate treatments.
Lastly, make sure to provide your plants with the correct cultural care. This includes proper watering, adequate sunlight, nutrient-dense and well-draining soil, and correct temperatures. If your calibrachoas are healthy and well cared for, serious instances of fungal diseases and infestations will be greatly reduced.
Conclusion
In summary, the most common causes of a dying calibrachoa are fungal diseases, overwatering, and a lack of proper care. Hopefully, this guide will help you address these issues as soon as possible, so that you can revive your beautiful flowers.
Image: istockphoto.com / BlueSkye Creative Inc.