Brown conifers are never a good sign. If the conifers do not have a rich, green colour, this indicates problems that could lead to the death of the plants over time. In the worst case, you will lose entire hedges, which you will have to replace with new ones. This gnaws on your wallet. However, you don’t have to despair because you can save brown conifers.
Conifers in the garden are used for a variety of different projects, ranging from individual positions to hedges. They inspire with their intense green, which, depending on the species, even shines through the winter and thus act as a permanent screen or colour aspect over the dark and snowy winter season.
The gardener’s heart becomes heavy when the conifers suddenly change their colour to brown, because in this case the plants are not doing well. It is now important to recognise the possible causes and how they are treated so that you can save brown conifers and thus preserve your garden diversity.
False Alarm: Brown Conifers in Winter
First of all: Not all conifers are green over the winter. Some species take on a brownish colour during the cold season, which is simply part of the rhythm of the plant. This brown colouring can either be a continuous brown or brown-red, or only a few areas change colour.
The winter colour is completely harmless if your plants do not turn pale brown, i.e. look ill. They should still have their typical character and the colour should be rich. The following conifers are typical for a brown winter colouring in different shades.
- Western Tree of Life (bot. Thuja occidentalis)
- Giant Tree of Life (bot. Thuja plicata)
- Carpet juniper (bot. Juniperus horizontalis)
- Hedgehog juniper (bot. Juniperus rigida)
Especially thujans are known for their brown colouring, which can affect the whole plant. The reason for this is the origin of these species, as they have to endure intensely cold winters, which means they have to save nutrients, which leads to brown colouring over the winter. This is comparable to the discoloration of the leaves of deciduous trees in autumn. Juniper, unlike thuja, has either a red or purple brown colour, which is equally worrying for many gardeners. So before taking any action, check to see if your taxa change colour in winter.
Tip: The Scots pine (bot. Pinus sylvestris) also colours over the winter, but this is not a brown shade. This one really bleaches out and turns yellow without the coniferous tree feeling bad.
Saving brown conifers
Saving Brown Conifers: 7 Identifying and Treating Causes
If you want to save brown conifers, you must know the individual causes and treat them accordingly in order to be able to enjoy a rich green plant again. The actual rich green plants from the tree of life to cypresses (bot. Cupressus) to the classic fir (bot. Abies) can suffer from a variety of problems that lead to the brown colouring of the leaves.
Fortunately, there are suitable solutions for each of the causes, with which you can maintain brown conifers healthy again. Below you will find the 7 typical causes of brown conifers and how to counteract them.
Dry stress is a typical conifer problem, because the plants themselves are quite thirsty. With very few exceptions, the location should always remain fresh, moist and permeable so that the plants can easily reach sufficient water. Drought stress is not only evident in light to yellow-brown needles, but also in their drying out.
This is often caused by dry, hot summers and long periods of frost in winter. It is not for nothing that the plants sometimes have to be supplied with water in winter.
You can use the following methods for treatment:
- carefully shorten dried shoots
- not to cut too deep into the old wood
- Increase water addition
- do not cause waterlogging
- water in the evening or better still in the morning
- thus moisture is preserved
- it is best to pour the water directly onto the root disc
- Dip pot conifers with root ball in water
- immerse until no more air bubbles rise up
- then drip off excess moisture
- With these measures, your conifers
- would have to recover. You can prevent a loss of moisture throughout the year if you allow a mulch layer at least five centimetres thick.
Another big problem is sunburn. Saving brown conifers is much more difficult in this case because you have to take measures to provide shade. This phenomenon only occurs directly after the plants have been pruned, as it often lasts from June to July and even into August if the species have a strong growth.
During this period, the sun shines directly on the freshly cut shoot tips, which then dry out and turn brown. Since the plant itself has already been weakened by pruning, the sun is particularly hard on it. Use one of the following tools to protect the conifers from sunburn for the first ten days after pruning.
- shadow nets
It is also recommended to choose a cloudy day for the cut of your conifers. This will significantly reduce the risk of sunburn on the shoot tips, which will also prevent brown conifers.
Nutrients are important for plants to perform their functions without problems. A lack of nutrients often causes brown needles to discolor over time. For this reason, a lack of important nutrients is not immediately apparent as this process is gradual.
The symptoms are as follows:
- Shoot tips turn brown
- Brown colouring spreads to needles
- take on yellow-brown colouring
- whole conifer turns yellowish brown
- In most cases, this is not due to a lack of fertiliser, but rather to incorrect soil conditions, which have a negative effect on the nutrient uptake of conifers. The plants themselves require only a few nutrients, but compacted and lean soils cause a lack of nutrients. In this case you should loosen up the compacted soil and mix some sand under the soil.
However, if the soil is poor, you should work in mature compost, horn shavings or stable manure that is well deposited. This gives the plants the necessary boost of nutrients. In general, it helps to enrich the soil with horn shavings and rock flour. If the nutrient deficiency is severe, you should use a conifer fertilizer after the soil has been adapted. This ensures quick results.
A rotting of the stem or roots by Phytophthora cinnamomi is fatal for the conifers. If the fungus has nested, needle discolorations in yellow-brown clay show up, which is however only the smallest problem. Over time, the roots, including the root neck, are destroyed, which in turn leads to discoloration of the needles. The plant then shrinks irrevocably. Unfortunately, brown conifers can only save if you notice Phytophthora cinnamomi early.
You should also avoid waterlogging, which is one of the main causes of the fungus. Approved fungicides such as Aliette WG from Bayer Garten should be used if suspected at the end of summer. If a specimen is infected, you should definitely dig it out and store it away from your other conifers and plants. The fungus is extremely invasive.
Other fungal infections also cause conifers to turn brown. Unfortunately, only cutting back the affected shoots helps to save the conifers. The following fungal infections can be mentioned here.
Pestalotia shoot death
brown shoot tips
Colouring reaches inside the leaf
Stains in black-brown are visible
Scaly and needle tan
infests older plants
Shoots in the lower area turn brown
Kabatina Branch Death
infests younger shoot tips
A pH value below 5.0 is harmful for conifers, which can be seen in brown areas, some of which can even be black. In this case, the soil is too acid, which you should definitely confirm with a pH test. If the pH value is in this range, you must increase it so that it reaches 5.5 to 6.5, which is ideal for the plants.
Use the appropriate amounts of lime for this:
pH value from 6.0 – 6.4: 150 – 180 g/m².
pH value below 6.0: 250 g/m² (sandy soil), 500 g/m² (loamy soil)
Road salt over the winter can severely damage conifers and even cause them to die completely. The salt extracts moisture from the soil, which leads to drought stress. It also destroys organisms that are involved in the formation of humus and thus nutrients in the soil. In addition to drought stress, the plants suffer from a lack of nutrients as a result of road salt, which is reflected in the corresponding damage patterns until the plants have completely atrophied.
It is very important not to plant conifers too close to sidewalks and roads. To save brown conifers, water them sufficiently in winter and remove brown shoots in spring. Also rinse the conifers well with water in spring.
Tip: Make sure to dispose of cuttings after a fungal infection or rot not on the compost, but in the household waste. The decay pathogens and spores can spread easily in this way and quickly infect healthy plants, which destroys all work.