Content
Various varieties of juniper are widely used in ornamental gardening and landscape design. This coniferous shrub remains green at any time of the year, it is quite unpretentious and is rarely affected by diseases that can spoil its appearance. However, he also has problems with the crown. If the juniper has turned yellow, you need to deal with it and look for the reasons.
Does juniper turn yellow in autumn?
The natural color of juniper scales or needles is green. It remains this way in the fall, but a slight change in color still occurs. This is due to the fact that juniper leaves synthesize anthocyanins - specific wax-like compounds that protect the tree from ultraviolet radiation. Their colors can vary from red to purple. In combination with the greenery of the needles, they give it a yellowish or brownish tint.
Juniper leaves turn yellow due to the release of anthocyanin not only in autumn. This is a natural reaction of the plant to worsening weather conditions, so a change in the color of the needles is observed, for example, in dry weather. Sometimes juniper needles turn yellow and fall off in the fall due to the death of old needles and their replacement by new ones. This is a natural process that occurs approximately once every 4 years.
Reasons why juniper turns yellow in the garden
There may be several reasons why juniper turns yellow. The most common are the following:
- Wrong choice of landing site.
- Violation of the rules of care.
- Disease.
- The appearance of pests.
Often there are several reasons for the yellowing of the crown. Therefore, it is necessary to find out without delay what is happening to the bush. To do this, a full inspection of the junipers is carried out, soil and water tests are done, and the presence of diseases and pests is checked.
Incorrect landing
Juniper often turns yellow after planting. This means that the site or soil is not fully suitable for it. Choosing the right place to plant juniper is of great importance. In the wild, this shrub most often grows in light pine or deciduous forests, along roadsides, in clearings and forest edges. The best place for it is partial shade, so an area that is too shady will not be suitable for it. The acidity of the soil should be close to neutral. Juniper also reacts very negatively to excess humidity, so planting it in a wetland is strictly not recommended.
The time of planting juniper in open ground is also important. This should not be done in the heat, in the middle of summer.The best time for planting is spring, April-May, as well as the first half of autumn, September or early October.
Particular attention should be paid to junipers taken from the wild. As a rule, they take root very poorly, so in most cases a bush brought from the forest will turn yellow, dry out and eventually die. Juniper plantings in most regions are under protection, this also needs to be remembered. Therefore, it is better to take plants from specialized nurseries. Such species take root much better and require less care.
Improper care
Juniper is quite unpretentious, but improper care can also cause yellowing of its crown. Most often this is due to insufficient watering. This especially applies to species that are grown under cover or at home. If a shrub grows in open ground, then it usually has enough natural precipitation. An exception is made only during dry periods, when it is recommended not only to water at the root, but also to irrigate the crown.
Another reason for the yellowing of juniper needles is associated with spraying shrubs. If you irrigate in bright sunny weather, the plant is guaranteed to get burned, especially on the sunny side. Since juniper leaves have a waxy coating, they are not completely wetted, and the water remains on them in the form of small round drops. In sunny weather, they become a kind of lens that focuses light and can burn through leaves. Therefore, irrigating junipers in clear weather is done only late in the evening or early in the morning, so that all the water on the foliage has time to dry completely.
The composition of the soil in which juniper grows is also important. Too large deviations in acidity in one direction or another negatively affect the color of the crown. Therefore, you need to be careful when applying fertilizers so as not to acidify or, conversely, lime the soil. You should also protect juniper from pets that relieve themselves on the trees, since their urine is highly alkaline. It is recommended to fence plants with netting, lattice, or use special repellents.
Adverse climatic conditions
Unfavorable climatic conditions can affect the appearance of juniper and the condition of its crown. Such problems can arise if the summer is, for example, too cold and rainy. In such conditions, even well-drained soils can turn into a swamp, and this is destructive for this shrub. Long periods of drought can also cause yellowing of the crown, especially in combination with dry, hot winds.
Pests
Juniper is quite often subject to pest attacks, especially in the southern regions. Often insects settle in the crown and feed on the juices of the leaves. Due to a lack of nutrients, the needles turn yellow and die, and in especially severe cases the tree may die.
The most famous insect pests of juniper are listed in the table:
Pest | Nature of the lesion | Ways to combat and prevent the appearance |
Aphid | Aphids suck the juice from young needles, causing them to turn yellow and die. | Cutting off young shoots with aphid colonies. Rinse with water pressure. Spraying 2 times during the season with Fitoverm or Karbofos, as well as folk remedies: infusion of garlic, tobacco or horseradish.Planting repellent plants, such as pyrethrum, in close proximity to the bush. |
Shchitovka | It parasitizes the shoots and needles of juniper, sucking out the juices. When the population is large, scale insects can kill shrubs. | Treatment of the crown with special preparations, for example, Aktara, Actellik or Karbofos. Severely affected shoots are cut off and burned. The crown can be treated with a weak solution of laundry soap and then rinsed with clean water. |
Needle mite | It feeds on the juices of young needles, which turn yellow due to lack of nutrients. It is detected by characteristic thickenings at the ends of the needles. | Spraying with Karate or Akarin preparations. Periodic spraying with infusions of garlic or tobacco, as well as treating the crown with a solution of laundry soap, followed by rinsing with clean water. |
Mining moth | A pest butterfly whose caterpillars gnaw out needles from the inside. | Treatment with Decis 2 times with an interval of 25 days. Autumn digging of trunk circles and soil treatment with fungicides. |
Angled-winged moth | A pest butterfly, it and its caterpillars feed on pine needles. | Spraying with Decis-Profi, Actellik or Fufanon. Damaged shoots are removed. |
Diseases
Juniper gets sick quite often, especially if it grows in unsuitable conditions. Here are the most common diseases found on this shrub.
Disease | Nature of the lesion | Methods of treatment and prevention |
Fusarium wilt (fusarium wilt) | Yellowing and falling of needles, drying out of shoots, starting from the top of the plant. Caused by soil fungi that cause root rot. | The infection appears when choosing the wrong place for planting or due to natural factors: insufficient lighting and excess humidity.Prevention is the culling of seedlings and adult plants, as well as planting in a more suitable place. Diseased plants are immediately removed and burned. As a preventative measure, juniper is sprayed with Vitarox or Baktofit, and the soil is impregnated with a solution of Fitosposrin. |
Drying of shoots | The infection is caused by fungi living on the tree bark. Affected shoots turn yellow and dry out, and the needles fly off. | Infected shoots are cut off and burned. The crown must be treated with a 1% solution of copper sulfate. |
Schütte (brown gray mold) of juniper | The causative agent of the disease is a fungus that primarily affects needles and young shoots. The affected branches become brown, but the needles do not fly off, but acquire a reddish-brown tint. | To reduce the likelihood of disease occurrence, it is necessary to prevent thickening of plantings and excessive humidity. There is no cure for Schutte. The affected plant must be dug up and burned. As a preventative measure, the shrub is treated with Bordeaux mixture twice a year. |
Rust | One of the most common diseases of juniper. Caused by fungi that appear on shoots, bark, and cones. They can be identified by the appearance of bright yellow or orange growths on the bark. | Affected branches must be pruned and burned. As a preventive measure, juniper is treated with Bordeaux mixture in spring and autumn. |
Cortical necrosis | Appears on shoots in the form of small brick-colored pads. Over time, the affected juniper dries out. Necrosis can also affect the roots of the plant. | As a preventive measure, plants are treated with Fundazol. Affected branches are cut off and burned. The soil in the root zone is shed with a solution of Fitosporin. |
Biotorella cancer | The fungus develops in cracks in the bark.After some time, the bark turns brown, the needles turn yellow and the shoot dies. | If a fungus is detected, the affected shoots must be cut off and burned. As a preventative measure, plants are treated with Hom or Abiga-Pik. |
The influence of seasons on plant yellowing
Although juniper is an evergreen shrub, its color may vary depending on seasonal factors. This applies to both species growing in the wild and ornamental garden shrubs.
Why does juniper turn yellow in summer?
Yellowing of juniper in the summer is most often associated with insufficient watering. If the crown has faded and begins to turn yellow evenly, the reason must be sought in improper care. If yellowing or browning is local or focal in nature, or individual branches, shoots or sections of the crown change color, then it is necessary to check the plant for the presence of disease or the appearance of pests.
Why does juniper turn yellow in autumn?
The uniform change in color of juniper as temperatures drop in autumn is a natural process. The amount of anthocyanins produced in the leaf blades increases, changing the color of the needles and giving them a golden or reddish-brown hue.
At the beginning of autumn, juniper often turns yellow inside. This is the death of part of the old needles, which are several years old. Thus, a natural process of replacing it with a young one occurs. In this case, the color change is uniform and appears only on the inner part of the needles.
Why does juniper turn yellow after winter or in winter?
In winter, juniper leaves turn yellow for the same reasons as in autumn. An additional reason may be damage to the crown by severe frosts or mechanical injury to the bush due to the weight of adhered snow. Frozen and broken branches will begin to turn yellow.In the spring, they need to be removed first, otherwise they will become breeding grounds for diseases and a home for insect pests.
Why does juniper turn yellow in spring?
The most common cause of yellowing of the juniper crown in spring is sunburn. This is due to the fact that under the influence of direct sunlight the coniferous cover heats up. Snowflakes stuck on the branches melt, turning into droplets of water. Each of these droplets becomes a magnifying glass that focuses the sun's rays. Therefore, quite often in early spring, on the sunny side, junipers literally burn out, the needles turn yellow or turn brown. To protect shrubs from sunburn, they are usually covered with a layer of gauze.
What to do if the juniper turns yellow and dries out
To determine the reason why juniper turns yellow or brown and begins to dry out, you must first conduct a full inspection of it for diseases or pests. This must be done very carefully, because, for example, the scale insect is skillfully camouflaged and it is quite difficult to notice it on the shoot.
Slight yellowing of juniper needles can often be eliminated by spraying the plant with an aqueous solution of Epin with the addition of Zircon. To prepare such a stimulant, you need to take 1 ampoule of each product and dilute them in 5 liters of water. Spray the juniper crown generously with the solution. You can do this several times with an interval of 3-5 days.
Juniper reacts quite strongly to atmospheric pollution, so it is not used for street landscaping.In areas located near industrial zones or along busy highways, problems with yellow tips of juniper needles can be directly related to poor environmental conditions. It is unlikely that this situation will be corrected, so it is worth looking for another place to plant juniper, and planting something more resistant to a polluted atmosphere on the site.
It must be remembered that the soil on which this evergreen shrub grows must be constantly moist, but not swampy. If every day there is obvious drying out of the soil in the root zone, this indicates insufficient watering. It is strongly recommended to mulch the tree trunks; this retains moisture well in the soil. It would be a good idea to check the acidity of the soil once again. This can be done using a test, which can be purchased at the store.
Preventive actions
Prevention is the best way to avoid problems with yellowing of juniper needles. The shrub must be regularly treated with fungicides to prevent fungal diseases. In addition, you need to regularly inspect it, and this must be done scrupulously and carefully. If you detect a disease or pests at an early stage, then, as a rule, it is possible to save the bush. Neglected diseases are treated much worse and in most cases lead to the death of the plant.
An important measure is comprehensive care of juniper tree trunks. Weeding, loosening and mulching them, as well as treating them with special preparations is an excellent preventive measure against the appearance of pests that overwinter in the root zone. The tree trunk circles, like the shrub itself, must be regularly cleaned of old wood, dry and broken branches.
In spring, measures should be taken to shelter the juniper from the bright sun. Young bushes and seedlings must be protected from direct sunlight first. It is better to use burlap for this. Covering material cannot be used for this purpose, as it prevents the evaporation of water. Sometimes, to protect from the sun, it is enough to install a small screen or a white screen that protects the juniper from direct sunlight.
Conclusion
If the juniper has turned yellow, it is necessary to immediately examine it and identify the cause. The sooner this is done, the greater the chance of returning the bush to a healthy decorative appearance. Juniper is a magnificent ornamental shrub that has a lot of useful properties. Therefore, you should not let the situation take its course. It is always better to understand and identify the reasons for the yellowing of needles in order to avoid this in the future.
