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The cherry laurel is very popular because it brings color to the garden with its dark green foliage, especially on dreary winter days. It is all the more annoying when it suddenly gets brown leaves and the leaves fall off. Here it is important to quickly identify the cause in order to be able to react correctly. The plant expert gives you all the essential information.
causes
If the leaves of a cherry laurel turn brown, this can have various reasons. You should definitely research the causes here, because if you don't react correctly, the Prunus laurocerasus threatens to die off in the worst case. The plant expert will tell you everything you need to know about possible reasons, how you can counteract this with appropriate treatment measures and what else you should know about brown cherry laurel leaves.
season
The season usually raises a suspicion as to why the leaves of cherry laurels are turning brown.
winter
This is most common between February and late March, depending on how cold the temperatures are. In this case, you can assume that your Prunus laurocerasus is suffering from the effects of the winter and will respond with brown foliage.
spring
When cherry laurels get brown leaves in spring, there is often less shoot growth. In most cases this is due to a pruning error in February/March.
summer
When the flowers slowly wither in June/July and fruit form, the Prunus laurocerasus needs special attention in terms of care. Mistakes in care are often noticeable here in the form of brown leaves, as is an incorrectly chosen location. Occasionally, parasites and diseases could be to blame for the brown discoloration of the leaves. Mushrooms show up especially during the wet seasons.
fall
If you have cut your laurel bush in summer, brown leaves, like in spring, could indicate that you did not cut well. But due to the usually higher humidity in autumn, a pest infestation cannot be ruled out, which should usually be fought before the onset of winter.
winter damage
dryness
Although most types of laurel cherries are frost-resistant and are very robust even at extreme minus temperatures, the winter can still cause them problems if it was too dry or if the plant did not get enough moisture due to its location. This is the case, for example, when many sunny days allow roses to evaporate too much moisture and frozen soil blocks adequate moisture supply to the roots.
A typical sign of a too dry winter period are brown leaves, which form mainly in early February, but also up to March. After discoloration, the leaves become increasingly drier and eventually die.
frost damage
Also in February, the brown color of the leaves indicates that there may be frost damage. This results from extreme sub-zero temperatures in winter and when the cherry laurel species is not particularly cold-resistant. If measures to protect against the cold have not been taken, such as laying a thick layer of straw or brushwood over the root area, frost damage is more common. Frost damage can also be recognized by so-called frost cracks in the woody parts of the plant and on dried-up branches.
Treatment:
Even if your cherry laurel looks badly battered, you can get it fit again. Brown leaves and dried and frozen shoots can be cut off between March and April until the tissue structure is healthy. In this way, you limit the damage in the event of extensive plant damage, as the plant does not have to unnecessarily waste nutrients on the plant parts that cannot be saved. In the case of minor damage, this measure is usually sufficient and the cherry laurel recovers quickly. Choose a dry, frost-free day for your work when cutting and do not forget to water so that any moisture deficits can be compensated.
After the ice saints in May, you should subject the affected cherry laurel to severe pruning if there is severe winter damage. This may mean that you have to go without a flower that year, but chances are that you will have a recovered and well leafed shrub in the garden by autumn.
- Shorten all dried and/or frozen twigs/shoots by two thirds
- The interface must be at least two to three centimeters in healthy tissue
- then cut the entire cherry laurel by half (stimulates bushy shoot growth)
- Water vigorously when there are many dead branches and leaves
- only cut on a dry, sunny day - preferably around noon
- seal larger cuts with charcoal powder or wax if necessary (to prevent disease)
TIP: Water your cherry laurels every now and then even in winter when the temperatures are milder. If necessary, break through the layer of ice above, but never use hot water, only cold water.
nutrient problem
When cherry laurels enter the growth phase in spring, they need a lot of nutrients until the fruit develops in summer. Especially if the soil conditions are not optimal, there can quickly be a lack of nutrients, which can lead to brown discoloration of the leaves. Many a hobby gardener means too well with his specimen and fertilizes too many nutrients. An excess of nutrients can also cause brown and dried leaves to develop. Here, a first discoloration of the leaf edges usually indicates a nutrient cause. Overall, the rose plant seems increasingly ill.
Treatment for nutrient deficiencies:
- Cut off the brown leaves and dried shoots from the cherry laurel
- Measure the pH of the soil, this should be between 5 and 7.5, if it is below 5 fertilize with lime
- loosen old soil if it is too compacted
- then apply long-term fertilizer such as horn shavings or compost
- optimally, if possible, transplant cherry laurel into fresh, nutrient-rich substrate
- Supply nutrient-rich fertilizer regularly about four weeks after transplanting
TIP: If the brown color extends from the edge of the leaf to the middle of the leaf, there could be a potassium deficiency. In that case, choose a special potassium fertilizer.
Treatment for nutrient overload:
- Cut off brown leaves and shoots
- water vigorously over a period of four days to flush out fertilizer
- then refrain from watering for a few days until the soil has dried
- alternatively: expose the root
- Use a garden hose to vigorously “flush” the roots in the planting hole
- allow excess water to sink as much as possible
- then refill the planting hole with low-lime soil or lime-free substrate
- only after about two months, slowly and carefully, start fertilizing again (minimized dosage)
TIP: If you find yourself in a heavy rainy season, you can let the rain work for you. Simply remove a lot of the upper layer of soil so that the cherry laurel still has stability and let the excess fertilizer be washed out by the rain.
Summer desiccation
The laurel cherry always needs a moist soil environment. If you don't water regularly on hot summer days, brown leaves will quickly appear, and later dried branches/shoots will also be clearly visible. The brown coloring here usually starts at the stem and then extends over the middle of the leaf until it reaches the leaf edges to the tip of the leaf.
If a drought is detected, excessive watering may only help to a limited extent, because if waterlogging forms, you may have the next problem, because yellow leaves and root rot can form. Therefore, proceed as follows.
- cut off all dried-up parts of the plant, including the leaves, right down to the healthy area
- water morning and evening
- do not water in the midday heat, because too much water evaporates here
- do not water in direct sunlight, otherwise burns may occur
In the case of very severe dryness and cherry laurels in tubs, it is advisable to "bathe" the root.
- Expose or dig out the root
- Cut off all accessible dried roots
- shorten all root tips by about one to two centimeters (improves moisture absorption)
- Fill the plant hole completely with water
- or place the dug up root in a bucket of water
- if no more air bubbles form, the root has become soaked with water
- Remove most of the excess water from the planting hole with a cup/small bucket
- remove the planted root from the bucket, drain well and plant in fresh, nutrient-rich substrate
- Refill the planting hole with dry, nutrient-rich soil
- water as usual from the following day
fungal infection
The robust rose plant is not armed against direct transmission of bacteria and viruses through infected cutting tools. If you have not thoroughly disinfected the scissors or knife before pruning in spring and/or autumn, fungal infections adhering to them can get into the interior of the plant through the fresh cuts. The leaves usually turn brown first, then dry up, while the entire laurel loses stability in branches and shoots.
In the case of fungal infections, such as shotgun disease, light spots also form on the leaves. Another discoloration begins at the edges of the leaves. Sometimes, depending on the type of fungus, sticky, white or silvery coatings can be seen on the leaves. Especially in humid autumn weather, mushrooms can also be grown without transferring a pruning tool.
Treatment:
- cut off all affected parts of the plant along with their branches or at the base of the stem
- Shorten the laurel cherry by about a third (stimulates new, strong growth)
- then carry out a treatment with a fungicide to combat fungi
- Repeat spraying twice at intervals of 14 days
pest infestation
If you discover feeding damage to the browning leaves, it could be a vine weevil infestation, which is considered a typical parasite of cherry laurels. Usually these marks can only be found on the edges and tips of the leaves. It usually appears between April and May and/or August and September. This beetle itself does not cause any life-threatening damage. It is its larvae that it deposits in the soil, which work their way down to the roots and then eat them.
Treatment:
Treatment with so-called nematodes has proven to be very successful. These are nematodes that are available in a clay mineral powder for use against vine weevil. These are added to the irrigation water and used to wet the plant and, above all, to pour the soil/substrate. The nematodes also transmit a deadly bacterium to the larvae and pupae with which to infect them.