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All about your cedar

Updated: Mar 19, 2023

Tout savoir sur les Thuyas

All about your cedar

Many gardeners are often confronted with a problem such as yellowing or drying of the needles on the cedar. Let's try to explain the causes and ways to deal with this plague.

From time to time, the needles of the cedar turn yellow in the fall, because at that time its life ends. The needle lasts about 3-6 years, then it starts to yellow and dies. Develops new. And so on. In this case, some branches yellow and dry up inside the crown around the trunk. There is no reason to worry, you just need to gently clean the plant of dried needles.

The second natural reason for changing the color of the needles is seasonal discoloration. This occurs in late fall and winter. The darkening and browning of the needles (almost brown) is a defense reaction to a drop in temperature. The bronze color is acquired in winter by eastern white cedar (almost all varieties except Smaragd ). With the arrival of spring heat, the needles return to their usual color. The real threat comes only from frosts of -30 degrees, at extremely low temperatures, the plant can die.

Care mistakes

If the needles turn yellow and dry out in the spring or summer, it may be due to improper maintenance. Often, a big influence on the condition of the plant has a soil composition. It is wrong to plant cedar on sandy soil, where water quickly goes to the lower layers; on clay soil, where the structure is dense, not enough oxygen and the root system can not develop normally; planting in low areas where water stagnates, where the root system dies and rots, is also destructive. Ideal for cedar soils - well drained, but moist for much of the year (sod with added peat and river sand).

A plant planted several years ago should be fertilized regularly (growth or density fertilizer for coniferous plants). With a lack of iron in the soil, the needles of the shoots become yellow or even turn white. With a lack of phosphorus, the young needles acquire a purplish-red hue, and with a lack of nitrogen, the cedar gets much worse, becoming weak and stunted.

Animal urine is also very bad for the condition and appearance of plants. The needles in the places of contact have a black tint.


Sometimes, after the snow melts, a disease called "brown schutte" is discovered in young cedar. It manifests itself in the following way: on the brown dead needles a black-gray cobweb comb forms. The needles do not fall for long, the thin branches die.

In spring for the prevention of fungal diseases every 3-4 weeks should spray "Fitosporin-M".

Fungi can also settle on the branches of thuja, destroying the bark tissue and vessels of the branches, causing necrosis. In this case, the needles also change color: they turn red, turn gray, turn brown and not uniformly, but in places, which then merge. Spores of the fungus in the form of dark spots, growths or bumps can be found on the trunks and branches.

Fungal diseases can also affect the stems and roots of plants. The lesion often occurs on poorly drained, clay soil with frequent water stagnation.

For the treatment of necrotic diseases and vascular wilt in the spring and fall, plants are sprayed with the preparations "Abiga-peak" or "HOM". With a strong defeat can be treated in summer. To control stem rot, the affected areas are cleaned and disinfected with a 1% solution. copper sulfate and cover with a garden soil.


If the needles turn brown with a gray bloom, ants crawl on them en masse, then it indicates a defeat of the plant by sucking insects. For example, aphids, bed bugs, tuyeva podzhashchitovkoy or juniper shield. Thuish false guards look like large brown buttons, and juniper ones look like small scars. They are attached to the base of the shooting. If at the base of the branches there are white formations like cotton, it is a mealy bug. With these pests will help to cope with the drug "karbofos" (spraying in early spring before budburst). During the summer you can spray "Aktellik" or "Rogor".

Larvae of the larch cutworm can weave the needles of the cedar into small dirty cocoons, damaged needles yellowing. If in the case of bark detachment, you found complex shapes and holes in the wood, the plant is populated with stem parasites. From these insects help medicines "Fufanon", "Aktellik", "Detsis Profi" (treatment in May-June).

Animal influence

Plants can be seriously affected by dog and cat tags. First, the root system reacts and only then the problem manifests itself in yellowing of the needles.

Diseases and pests

After the cold winter, cedar needles are often affected by brown mold. It is called brown.

If you have managed to correctly determine why the cedar begins to yellow, the plant can be saved and will please you for many years with lush vegetation.

Conifers are unassuming and durable. But even these mighty giants are prone to various types of disease.

Against stress

In any stressful situation (transplanting, pruning, disease, summer drought), the plant should be supported with anti-stress drugs "Zircon", "Megafol", HB-101. The treatment is carried out by spraying the crown several times during the period of exposure to stressful conditions.

A change in color of the leaves of cedar can occur for a very large number of reasons. And the sooner the correct one is determined, the greater the chance that the plant will continue to enchant with its beauty for a sufficiently long period. To do this, you must carefully examine the tree and try to establish why this has occurred.

Causes of yellowing cedar

The main reasons for the yellow cedar are:

-Natural processes.

-Changing the color of the season.

-Mistakes made in landing.

-Problems in care.




y spring, you should be concerned. It means that the tree is not feeling well or that something is missing.

kage becomes brown.

However, these symptoms are not characteristic of this disease. To confirm the diagnosis, it is necessary to detect the spores of the fungi, which appear as brown spots, as well as tubers with a diameter of 1-2 mm.


The rogue deflection consists of small, light yellow insects, when an individual dies, the larvae remain under a false shield (skin), hence the name.

Signs of disease: 3-5mm are placed at the back of the needles. semi-circular individuals. Needles begin to dry out, needles partially dry out and stand out clearly from the general view.

The spider mite is a particularly dangerous insect in hot weather. During summer periods, a female can carry up to 6 generations of larvae. It is the larvae that damage the needles.

Signs of disease: presence of a thin and abundant layer on the shoots. If you look closely at the scales of the cedar, you can see many small yellow spots, followed by fading brown areas. The damage is most noticeable in late summer, early fall.

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