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Lavatera is one of my favourite shrubs, but one common problem with them is that the leaves often start to turn yellow, especially on more established plants.
If you notice your Lavatera’s leaves yellowing, there might be a problem. Instead of guessing what the problem could be, it is better to investigate and figure out what really going on. Firstly, I just want to highlight a couple of things you need to consider before jumping in and blaming pests or diseases or growing environments on the plant’s yellowing leaves.
Lavatera is generally a short-lived plant, after around 4 years they start to become past their best, even after pruning every spring which I recommend and talk about here. They start to suffer from yellowing foliage and fewer flowers so if you have a Lavatera that has been planted for a number of years, it might just be time to replace it.
If however, you have had your mallow for only a year or two, then it could be something else such as overwatering, pests or growing conditions etc. Below are the typical reasons behind your plant’s leaves turning yellow:
If your Lavatera is being overwatered, causing the leaves to turn yellow
Lavatera’s need water. Especially at the younger stages before it is fully established and they usually need a good amount of watering, even more so if they are being grown in pots. However, overwatering the plants is a disaster waiting to happen, mainly for the roots. Roots sitting in waterlogged soils cannot absorb enough oxygen and fungi spores in the soil slowly infiltrate the plant. If diseases like root rot take hold of the plant, the foliage will be affected and start to discolour causing the leaves to start turning yellow.
As a preventative measure, water the plants periodically, giving enough time for the plant to absorb the water before adding more. Also, make sure you plant your Lavatera in soil that drains well to avoid waterlogging issues. The key is really to make sure the soil is well-drained.
Pest attacks such as spider mites can cause leaves to turn yellow and curl
You also need to check if there are pests around causing damage, as there are several pests that attack Lavatera including scales, thrips and spider mites. Take a close look at the leaves and the rest of the plant to see if you can spot any signs of an infestation. Do not forget to look under the leaves because that is where most pests begin damaging the leaves.
If you see any insects or evidence such as small webs (as in the case of spider mites), I recommend spraying with a general pesticide that will be available from most local garden centres and nurseries.
For those who don’t want to spend money on chemical-based control methods, you can go with organic methods such as using natural predators or neem spray.
Too much sun and not enough shade can cause yellowing leaves
When planting Lavatera, placing them in a sunny spot is a good idea because they need several hours of sunshine to thrive. However, there are days that the sun is too hot and the plant lacks enough water to keep hydrated. Long exposure to the scorching sun will result in sunburnt leaves and wilting. On days that the sun is too hot, make sure you supply the plants with enough water to keep the heat from damaging the leaves.
Alternatively, if you have a potted Lavatera, move the pot somewhere they can access partial shade from the sun.
Fungal and bacterial diseases such as rust can cause yellowing of Lavatera leaves
Plants are prone to both pests and diseases and Lavatera shrubs are no exception. From fungal infections like root rot and rust to bacterial infections such as leaf spot, you can find the plants weaken from time to time.
Diseases are not hard to miss because the leaves begin to discolour followed by the rest of the plant. One of the most common is rust, this forms on the underside of the leaves but not before the leaves begin to turn yellow.
Take note of any symptoms, compare the characteristics with information online and find the specific disease. Most diseases, including rust, can simply be treated by removing affected leaves and treating with a fungicide spray at the first signs.
Poor quality soil
Just as humans need vitamins and minerals to stay healthy, so do plants. If you plant your Lavatera in poor soils that lack nutrients, it will only be so long before they start struggling and yellowing leaves is usually the first sign of poor soil. Lack of crucial minerals such as phosphorus, calcium, potassium and boron (amongst others) can cause leaf discolouration.
If you have ruled out all the other causes of yellowing leaves, check the soil. Conducting a soil test is the fastest way for you to rule out nutritional issues behind the appearance of yellowing leaves. The easiest way to resolve this is to improve the soil by applying fertilisers such as bone meal, fish blood and bone or even good old well-rotted manure, this is also great for using as a mulch to help the soil retain moisture.
That’s it for this guide on why your Lavatera might have yellow leaves. Remember that older plants may just need replacing as they are short-lived. In general, if you provide good growing conditions, well-drained soil in a sunny position they should grow well with just pests to look out for.
Read next: You can learn how to grow Lavatera here or if you have a plant that is not flowering well, check out my guide on why your Lavatera might not be flowering here