What to Do When Sabina vulgaris Leaves Turn Yellow? Causes and Solutions Explained

In landscaping, Sabina vulgaris (Savin juniper) can be used as evergreen ground cover or for foundation planting, adding layers of greenery, and it is also a good ground cover plant for slope protection. However, with improper management, yellowing of leaves can occur, and the main causes are as follows:

Soil too dry

Although Sabina vulgaris is suited to growing in dry sandy soil, if it remains in a dry soil and air environment for a relatively long time, the leaves at the lower part of the branches are prone to turning whitish and yellow. If it is not a grafted seedling, especially a grafted seedling not using Platycladus orientalis (Chinese arborvitae) as rootstock, this condition is even more likely to occur.

Control measures

Water moderately until thoroughly soaked. At the same time, Sabina vulgaris requires a loose, well-aerated ecological environment; if the soil remains in an overly wet state for a long time, the plant will suffer root rot due to lack of oxygen, and the leaves will turn yellow, especially the new leaves. Therefore, the amount of watering should be controlled, and the soil should be loosened appropriately for aeration. Sometimes excessive fertilization can also cause yellow leaves, so the amount of fertilizer should be controlled.

Disease

The mycelium of Sabina vulgaris rust overwinters on junipers and cypresses. In February to March of the following year, the teliospores mature, and the galls absorb water, swell and crack; when conditions are suitable, a large number of basidiospores are produced, beginning infection of the alternate hosts, which include Rosaceae plants such as crabapple, hawthorn, pear and apple. In early May, aeciospores are produced, and June is the peak period of the disease; from August to September the aeciospores mature and are spread by wind to conifers such as Sabina vulgaris. The disease mainly harms the needles and young shoots of Sabina vulgaris. In the early stage of the disease, small orange-yellow, glossy spots appear on the leaves, then gradually expand, and on the spots are borne small yellow dots the size of pinheads; in humid weather, mucus is secreted on them, and after drying the yellow dots turn black, which are the pycnidia of the pathogen. The following year, upon rain they germinate and produce basidiospores, spread by wind and rain. In warm, rainy spring years, the disease is severe. If scattered yellow dots appear on young branches and leaves, it is generally this disease.

Control measures

Prune out diseased branches in winter. From October to November, spray a mixture of 0.3% sodium pentachlorophenate and 1 degree Baumé lime sulfur on Sabina vulgaris to prevent infection by rust spores. In mid-to-late March, before the teliospores germinate, spray 1 to 2 degrees Baumé lime sulfur or an equal-amount formula 160 to 200 degrees Baumé Bordeaux mixture 2 to 3 times, once every 7 to 10 days, for a good effect.

Insect pests

If small patches of Sabina vulgaris turn yellow in a continuous area, after ruling out disease, it may be damage by stem-boring pests (such as longhorn beetles). Carefully check the branch and trunk areas to see whether there are frass holes, or break off the withered yellow branches to see whether there are larval tunnels caused by longhorn beetles.

Control measures

Strengthen the maintenance and management of Sabina vulgaris, enhance tree vigor, and reduce opportunities for pest invasion. Use a syringe to inject 30 to 50 times diluted 80% dichlorvos emulsifiable concentrate into the borer holes in the branches and trunks of Sabina vulgaris to kill the larvae. Before injection, remove the wood shavings and frass from the tunnels; after injection, seal the tunnel openings with clay. If the pest damage is severe, they can be cleared and burned in a concentrated way.

Physiological chlorosis

If a large area of spreading Sabina vulgaris turns yellow, no pests or diseases are found, and the soil moisture is moderate, it may be physiological chlorosis of Sabina vulgaris. In the early stage of chlorosis, the leaves turn yellow, then appear yellow-white, with the new leaves showing the most obvious symptoms. In severe cases, the leaf tissue necroses, affecting normal photosynthesis, and then the whole plant slowly dies. It is usually because the soil and water in northern regions contain more alkaline salts, which affects the plant's absorption of iron ions, causing physiological iron deficiency in the plant and leading to chlorosis.

Control measures

Ferrous sulfate can be mixed into fertilizer and applied. Mix 2.5 kg to 3 kg of ferrous sulfate, 5 kg to 7.5 kg of oil cake, 10 kg to 15 kg of manure, and 200 kg to 250 kg of water, and use after it has decomposed and turned black; spray a 0.2‰ ferrous sulfate solution, covering both the upper and lower surfaces of the leaves, once every 3 days, for several consecutive times, which can improve the yellowing of young leaves.

The causes of yellowing leaves in Sabina vulgaris are sometimes single, and sometimes caused by the combined influence of two or more factors, which requires careful analysis, careful diagnosis, and treatment according to the cause.

Causes and Solutions for Yellowing Leaves of Sabina vulgaris

Symptoms of leaf yellowing caused by longhorn beetle damage

April 10 news from China Landscape Web: In landscaping, Sabina vulgaris can be used as evergreen ground cover or for foundation planting, adding layers of greenery, and it is also a good ground cover plant for slope protection. However, with improper management, yellowing of leaves can occur, and the main causes are as follows:

Soil too dry

Although Sabina vulgaris is suited to growing in dry sandy soil, if it remains in a dry soil and air environment for a relatively long time, the leaves at the lower part of the branches are prone to turning whitish and yellow. If it is not a grafted seedling, especially a grafted seedling not using Platycladus orientalis (Chinese arborvitae) as rootstock, this condition is even more likely to occur.

Control measures

Water moderately until thoroughly soaked. At the same time, Sabina vulgaris requires a loose, well-aerated ecological environment; if the soil remains in an overly wet state for a long time, the plant will suffer root rot due to lack of oxygen, and the leaves will turn yellow, especially the new leaves. Therefore, the amount of watering should be controlled, and the soil should be loosened appropriately for aeration. Sometimes excessive fertilization can also cause yellow leaves, so the amount of fertilizer should be controlled.

Disease

The mycelium of Sabina vulgaris rust overwinters on junipers and cypresses. In February to March of the following year, the teliospores mature, and the galls absorb water, swell and crack; when conditions are suitable, a large number of basidiospores are produced, beginning infection of the alternate hosts, which include Rosaceae plants such as crabapple, hawthorn, pear and apple. In early May, aeciospores are produced, and June is the peak period of the disease; from August to September the aeciospores mature and are spread by wind to conifers such as Sabina vulgaris. The disease mainly harms the needles and young shoots of Sabina vulgaris. In the early stage of the disease, small orange-yellow, glossy spots appear on the leaves, then gradually expand, and on the spots are borne small yellow dots the size of pinheads; in humid weather, mucus is secreted on them, and after drying the yellow dots turn black, which are the pycnidia of the pathogen. The following year, upon rain they germinate and produce basidiospores, spread by wind and rain. In warm, rainy spring years, the disease is severe. If scattered yellow dots appear on young branches and leaves, it is generally this disease.

Control measures

Prune out diseased branches in winter. From October to November, spray a mixture of 0.3% sodium pentachlorophenate and 1 degree Baumé lime sulfur on Sabina vulgaris to prevent infection by rust spores. In mid-to-late March, before the teliospores germinate, spray 1 to 2 degrees Baumé lime sulfur or an equal-amount formula 160 to 200 degrees Baumé Bordeaux mixture 2 to 3 times, once every 7 to 10 days, for a good effect.

Insect pests

If small patches of Sabina vulgaris turn yellow in a continuous area, after ruling out disease, it may be damage by stem-boring pests (such as longhorn beetles). Carefully check the branch and trunk areas to see whether there are frass holes, or break off the withered yellow branches to see whether there are larval tunnels caused by longhorn beetles.

Control measures

Strengthen the maintenance and management of Sabina vulgaris, enhance tree vigor, and reduce opportunities for pest invasion. Use a syringe to inject 30 to 50 times diluted 80% dichlorvos emulsifiable concentrate into the borer holes in the branches and trunks of Sabina vulgaris to kill the larvae. Before injection, remove the wood shavings and frass from the tunnels; after injection, seal the tunnel openings with clay. If the pest damage is severe, they can be cleared and burned in a concentrated way.

Physiological chlorosis

If a large area of spreading Sabina vulgaris turns yellow, no pests or diseases are found, and the soil moisture is moderate, it may be physiological chlorosis of Sabina vulgaris. In the early stage of chlorosis, the leaves turn yellow, then appear yellow-white, with the new leaves showing the most obvious symptoms. In severe cases, the leaf tissue necroses, affecting normal photosynthesis, and then the whole plant slowly dies. It is usually because the soil and water in northern regions contain more alkaline salts, which affects the plant's absorption of iron ions, causing physiological iron deficiency in the plant and leading to chlorosis.

Control measures

 Ferrous sulfate can be mixed into fertilizer and applied. Mix 2.5 kg to 3 kg of ferrous sulfate, 5 kg to 7.5 kg of oil cake, 10 kg to 15 kg of manure, and 200 kg to 250 kg of water, and use after it has decomposed and turned black; spray a 0.2‰ ferrous sulfate solution, covering both the upper and lower surfaces of the leaves, once every 3 days, for several consecutive times, which can improve the yellowing of young leaves.

The causes of yellowing leaves in Sabina vulgaris are sometimes single, and sometimes caused by the combined influence of two or more factors, which requires careful analysis, careful diagnosis, and treatment according to the cause.