Conifers turn brown: this is how arborvitae, thuja & Co turn green again

Every hobby gardener wants a green hedge made of conifers and a tree of life planted as a solitary tree looks more impressive if it has no brown spots. But where do the brown needles come from? It is not always necessary to take action against this. It is important to recognize whether this is the annually recurring phenomenon or whether it is more a disease caused by a care error or a pest infestation. How thujas turn green again is explained below.

Most common cause

Ultimately, all trees of life get brown needles from the inside. Hobby gardeners often notice this behavior when there is less sunshine in autumn and it is also lower. The main cause is the lack of sunlight, which the thuja gets from the inside of yellow to brown needles and branches. The following also happens in such a case:

  • brown needles and twigs to the outside
  • mostly seen in September / October
  • Needles fall off
  • when winter comes, the tree recovers
  • new, green needles form in spring
Tip: Just as the trees turn their leaves brightly in autumn and lose them later, so the conifers get brown needles in autumn, which also fall off. Nothing needs to be done about this, the plant is neither sick nor does it suffer from pests.

Treat plant

If brown needles appear and winter sets in, the conifers need special treatment so that they can sprout again next spring. To do this, all brown twigs and needles should be removed from the tree. The procedure is as follows:

  • Remove the brown needles by hand
  • wear gardening gloves against injuries
  • also snap off dried twigs with your fingers
  • scissors are usually not required
  • it can also be tackled harder with the hands
  • healthy twigs and needles are firm enough
  • this also removes any pests
  • Tree is well ventilated in winter
  • drives out other pests inside
Tip: You may also want to wear a face mask during this work. Many insects, pests and dust settle in dense hedges in particular. These are whirled up during work and dust may be inhaled.

Brown needles due to care errors

There can always be a mistake in the care if the thuja forms brown needles. Especially if these brown spots appear on the plant at other times of the year than autumn, when this is the normal time for them. In such a case, the location, watering and nutrients should be reconsidered. The maintenance errors usually look like this:

  • wrong location
  • too much midday sun
  • young shoots and needles turn brown
  • too dark in the shade
  • a light, bright location is desired
  • Soil condition
  • compacted and too wet
  • Waterlogging
  • wrong fertilizer application
  • too little or too much watering

Often it is due to the lack of nutrients that the tree of life turns brown. For this reason, the plants need a cure with Epsom salts once a year. In this case, the plants receive 100 grams of Epsom salt per meter of height. The process is repeated several times; excessive watering should be avoided during this time so that the salts are not washed away.

Tip: If all rescue measures no longer help a conifer that has turned brown and apparently no mistakes have been made in care, then only disposal helps. In such a case, consider whether the plant is too old.

Eliminate maintenance errors

If it is determined that there may be a mistake in the maintenance, then you should react immediately. In order to prevent the brown needles, which do not naturally appear in autumn, the following things should be taken into account when planting:

  • Choose a location that is as partially shaded as possible
  • Morning and afternoon sun is desired
  • Well-drained, sandy and loamy soil
  • pH between 7 and 8 is ideal
  • Avoid waterlogging
  • Apply drainage
  • water regularly
  • Avoid drying out
  • add nutrients with compost in summer and autumn
  • too many nutrients damage the plant

In order to achieve the correct pH value, the real value in the soil is determined with a test set from a well-stocked gardening specialist. If the value is too low, lime can then be added. If the pH value in the soil is too high, it can be reduced by incorporating peat, mulch or humus.

Tip: Even a location on a busy road can be very damaging to the conifers due to the excessive exhaust gases that result.

Fight pests

Haben sich Schädlinge im Lebensbaum eingenistet, dann heißt es auch hier, schnell zu handeln. Meist sind hier Blatt- oder Schildläuse zu finden, die in großen Mengen die Zweige und Nadeln aussaugen und diese hierdurch braun werden. Wird ein Schädlingsbefall festgestellt, sollte wie folgt gehandelt werden:

  • alle befallenen Triebe entfernen
  • nicht auf den Kompost geben
  • besser im Restemüll verschlossen entsorgen
  • Sträucher mit kräftigem Wasserstrahl abspülen
  • Lösung aus Seife und Spiritus herstellen
  • die Pflanze mehrere Tage hintereinander einsprühen
  • auch reiner Alkohol mit Wasser gemischt kann helfen
  • im schlimmen Fall mit Insektiziden behandeln

Weitere gefährliche Insekten für die Thujabäume sind Miniermotten, Nadelholzspinnmilbe sowie auch Borken- und Rüsselkäfer.

Krankheiten erkennen

If diseases color the conifers brown, then it is a question of fungal diseases. These include rust fungi, pine chutes and thuja scale tan, which are often responsible for brown needles and twigs in conifers. In this case, too, action must be taken quickly to save the plant. Therefore, in such a case, you should proceed as follows:

  • Call in experts
  • the layman can hardly recognize the different types of mushrooms
  • remove all affected twigs and branches
  • Put directly in the waste and close tightly
  • Otherwise, fungus can spread in the garden
  • proceed with fungicides
  • Replace the soil around the plant
  • also dispose of in residual waste
  • Also apply fungicides on and in the soil
Tip: If only a few plants in a hedge are affected by the fungal attack, they should be carefully dug up and placed in quarantine far away from the rest of the hedge. Only when the plants have been completely freed from the fungus can they return to their place in the hedge.

Wrong cut

A hedge needs to be cut back. But a radical cut usually leads to the fact that shoots and needles turn brown. These brown spots also have the disadvantage that they never turn green again and irreparable damage occurs. It is therefore important that the tree of life receives a regular, moderate annual pruning. Therefore, when cutting, proceed as follows to prevent brown areas:

  • Cut back once or twice a year
  • once in late winter
  • around St. John’s Day in June
  • never into the old wood
  • Thuja then no longer sprouts
  • always leave a few green needles on branches
  • always only topiary from the outside
  • Remove old, brown shoots from the inside

Conclusion
There are many ways conifers can develop brown spots. If this happens in autumn, then this is a natural shedding that does not damage the plant and it turns green again in the next spring. At other times of the year, however, there may be mistakes in care, diseases or pests that need to be identified and remedied so that the thuja does not suffer any further damage and can recover.

Kira Bellingham

I'm a homes writer and editor with more than 20 years' experience in publishing. I have worked across many titles, including Ideal Home and, of course, Homes & Gardens. My day job is as Chief Group Sub Editor across the homes and interiors titles in the group. This has given me broad experience in interiors advice on just about every subject. I'm obsessed with interiors and delighted to be part of the Homes & Gardens team.

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