Why do rose leaves turn yellow and fall off in summer? What should I do?

Yellowing and leaf drop are a natural reaction of roses to falling temperatures and shorter daylight hours in autumn. However, the appearance of yellow leaves on a bush in summer or spring is unusual for these flowers and requires the gardener's attention. Not only spots and stripes, but uniform leaf color changes can also be a symptom of pathological processes.

Possible reasons

There's no single treatment for yellowing rose leaves, as this reaction can have various causes. Most often, the problem is caused by:

• inadequate care;
• malnutrition;
• exposure to pathogenic microorganisms;
• pest activity on rose bushes.

Environmental conditions

Often the appearance of yellow leaves is caused by unfavorable conditions:

• Insufficient light. This occurs in roses grown in greenhouses or shady areas of the garden. Leaves turn yellow on the part of the bush that receives the least sunlight, while the rest of the foliage appears healthy. Typically, the lower leaves are affected. The bush blooms poorly, the shoots are unnaturally thin and long, resembling vines, and the flowers may be pale and small.
• Overwatering. Prolonged periods of rain or overwatering are detrimental to plant roots, especially when grown in heavy clay soils or low-lying areas with poor drainage. Lower leaves are the first to turn yellow and fall off.

• Drought. In addition to yellowing, under-watering can cause rose leaves to curl at the edges and tips. The yellow color turns brown, and the leaves dry out. Stem growth and flower drop are also common.
• A sudden change in temperature. In this case, the leaves quickly change color and fall off, and the bush immediately loses a significant portion of its foliage.

Nutritional deficiencies

Yellow leaves may indicate a deficiency of certain nutrients in the rose's diet:

1. Nitrogen. In this case, the leaf turns pale, then takes on a uniform yellow color. Symptoms first appear on the lower leaves, and gradually the entire bush takes on an "autumnal" appearance. In the spring, nitrogen deficiency can cause color changes in young shoots—the shoots turn brown-yellow or pale orange, while normally they should be dark purple. The leaves on these shoots turn yellow-green instead of red.
2. Potassium. Older leaves are affected, with the tips initially discolored. Later, the yellowing spreads from the edges toward the center, but does not affect the veins. The edges of the leaf blades turn brownish-purple and dry out.
3. Calcium. Light yellow spots appear on the leaves, and the edges curl downward. Young foliage grows small, and the tips of the shoots dry out.
4. Iron. Characterized by small, yellowed, and curled young leaves. Large chlorotic spots appear on older leaves.
5. Manganese. Formation of yellow stripes and spots on the lower leaves. However, the veins and small areas of tissue around them remain green. Yellowing begins at the edges of the leaf blade.

Rose diseases

Certain fungi, bacteria, and viruses can cause yellowing and leaf drop on rose bushes:

1. Black spot. This disease is caused by a fungus, and symptoms typically appear in the second half of summer. Initially, brown spots with a yellow border appear on the leaves and stems of roses. Later, the leaves turn yellow, curl, and fall off. The bush may lose most of its foliage. Shoots stop growing, and flowering fails.
2. Yellows. A bacterial disease in which yellowing of leaves begins at the veins and gradually spreads to the rest of the leaf blade. Leaves may curl or curl upward.
3. Cressea mosaic virus. Yellow-green speckles and spots appear on the lower leaves, followed shortly by massive leaf drop.
4. Tomato rot virus. Yellowing is preceded by the appearance of light spots and lightening of veins on young leaves. Subsequently, the leaves turn yellow, become deformed, and develop necrosis. Abnormal flower shapes are observed, and spots may appear on the petals.

Impact of pests

Yellowing of leaves accompanies attacks of insects such as:

1. Spider mites. Symptoms are preceded by the formation of numerous white spots on the leaves, which eventually develop into discolored patches. The mites reside on the undersides of leaves, and their small size makes them difficult to spot with the naked eye. With extensive infestations, the leaves appear dusty on the undersides, a fine webbing appears on the plant, and shoots die.
2. Aphids. They often appear shortly before roses bloom. Small insects (up to 2 mm long) appear on young leaves and shoots. They can be green, red, black, or white. Winged varieties also exist. Leaves become thin, curl, and turn yellow, and patches of sticky coating appear on the plant. Shoot tips curl, and buds become deformed and fall off without opening.
3. Rose scale insects. They appear on roses less frequently than aphids or spider mites. The pest can be identified by red and yellow spots on the leaves, sticky spots on the plant that eventually turn black, and stunted shoot growth. Gradually, the leaves turn yellow and curl, and white growths, which are scale insects covered in waxy shells, appear on the undersides of the leaves and on the shoots.
4. Root-knot nematode. Externally, nematode infestation manifests itself as weakened bushes, poor flowering, and the appearance of small, deformed flowers. Leaves turn yellow, then brown and curl. If you dig up the diseased plant, you may find swellings and nodules on the roots. These growths are caused by the growth of root tissue, which the pest has penetrated.

Resuscitation of roses after exposure to unfavorable conditions

If roses have turned yellow due to poor conditions, the first step is to eliminate the underlying cause. Bushes suffering from lack of moisture should be watered with warm water. If the soil is overwatered, stop watering for a week or install a removable, waterproof cover to protect them from precipitation. If daily temperatures fluctuate significantly, cover the bushes at night. If the roses are reacting due to a lack of light, replanting them will help.

Resuscitation measures can help eliminate the effects of stress experienced by plants:

1. Water the bushes with Zircon (1 ampoule per bucket). You can add an ampoule of Cytovit to the solution or dissolve 1 g of Kornevin. Pour 1.5-2 liters of the solution under the bush, and water the plant with clean water immediately before applying.
2. After 3 days, it is recommended to treat the bush with the drug "Epin" (8-10 drops per 1 liter).
3. 14 days after watering with Zircon, it is necessary to feed the plant with potassium humate.

If roots are damaged (due to standing water or prolonged dry soil), give the plants an unscheduled phosphorus fertilization—this will help the rose grow new roots faster. In other cases, a potassium fertilization is sufficient to boost the plant's immunity. Foliar application is recommended for rapid nutrient absorption—in this case, dilute 15 g of superphosphate or 10 g of potassium sulfate per bucket of water. You can combine both elements in a single fertilization using monopotassium phosphate (10 g per 10 liters).

Providing basic conditions for growing roses will help prevent yellowing of leaves:

1. Plant in a well-lit area. The bush should be exposed to direct sunlight for at least 5-6 hours per day.
2. Ensure soil moisture drainage. When growing in low-lying areas, bushes should be raised above the ground level, i.e., planted on an artificial mound of soil. In heavy soils, sand should be added before planting to loosen the soil.
3. Optimal watering regime. Rose bushes need to be watered once a week, giving each one 10 liters of water. If regular care isn't possible, mulching the area around the trunk with peat or freshly cut grass will help conserve moisture. In hot summers, water twice every 7 days. The water should be warm.

Replenishment of nutritional deficiencies

If nutrient deficiencies are detected, roses should be given an unscheduled fertilizing. If micronutrient supplementation (iron, calcium, manganese) is required, the bushes should be sprayed with nutrient solutions. Potassium and nitrogen should be applied both through the foliage and into the soil.

1. Nitrogen. Root fertilization with urea (15 g per bucket—enough for 2 plants) or ammonium nitrate (17 g per 10 liters). Urea alone can be used for foliar feeding; in this case, 5 g of the substance is dissolved in 10 liters. Plants experience their greatest need for nitrogen in the spring.
2. Potassium. Foliar feeding with potassium sulfate (10 g per bucket of water) or potassium nitrate (7 g) is recommended, and potassium magnesium sulfate should be applied to the roots.
3. Calcium. Give calcium nitrate (15 g per 10 liters).
4. Manganese. Spraying with manganese sulfate (5-10 g per bucket).
5. Iron. For supplemental feeding, use solutions of "Micro-Fe," "Ferrylen," and "Ferovit" according to the instructions.

Prevention consists of applying all required fertilizers throughout the season and monitoring the plant's condition. There are additional factors that affect plant nutrient uptake:

1. Light and sandy soils are deficient in nitrogen. In cold weather and when potassium is deficient, plants are less able to absorb the element from the soil.
2. Heavy and peaty soils are deficient in potassium. Plants' receptivity to the substance is reduced by high calcium and magnesium levels in the soil.
3. Calcium is often low in acidic and peaty soils.
4. Iron and manganese deficiencies are most often observed in bushes growing in alkaline soils.

Treatment and prevention of diseases

One of the worst-case scenarios is when yellowing leaves are caused by disease. This symptom is typical of serious illnesses, some of which (viral) have no effective treatment.

Black spot

Fungus-damaged rose shoots and leaves should be pruned, followed by spraying. Black spot can be treated with fungicides such as Skor, Ridomil Gold, Strobi, Falcon, Profit, and Oxyhom.

Effective folk remedies include treatment with a solution of copper sulfate (1%) or Bordeaux mixture (1%), sulfur solution (0.3%), green infusion, and horsetail decoction. Dusting the bushes with wood ash is also used.

To prevent black spot, it is recommended:

1. Avoid excess nitrogen. Provide plants with adequate phosphorus and potassium.
2. Take care to bring the soil acidity back to normal – the disease most often affects roses growing in acidic soils.
3. Avoid dense planting of bushes, regularly clear the flowerbed or flower garden of weeds.
4. Carry out preventative spraying of bushes with copper sulfate or Bordeaux mixture twice a year - before the sap begins to flow in the spring and before wintering.
5. During the season, treat the bushes several times with the biofungicide Fitosporin (also prevents bacterial infections).
6. Plant lavender or sage near the rose bushes.

Rose jaundice

If symptoms of the disease appear, remove damaged shoots and leaves and treat with antibacterial agents such as Fitosporin, Fitoflavin, and Sporobacterin. These biological agents are safe for rose bushes and adjacent plantings. Yellowing that spreads to the entire bush is a sign that the plant should be destroyed. Affected roses, as well as any leaves removed during pruning, should be burned.

Prevention of jaundice:

1. Control of insects that carry bacteria. Yellows is spread by leafhoppers and psyllids.
2. Disinfection of garden tools with alcohol or a solution of potassium permanganate (100 g of potassium permanganate per bucket of water).

Arabis mosaic virus and tomato bronzing virus

Treatment and prevention for these viruses are the same. In the initial stages of the disease, pruning of affected leaves and shoots is recommended. The cut areas should be disinfected with charcoal powder or a pale pink solution of potassium permanganate. If the disease continues to progress, the affected bush should be dug up and burned to prevent the spread of the pathogen to other plants. There are no effective treatments for viral plant diseases.

Prevention of viruses in roses:

1. Control any sucking rose pests—these insects are the main carriers of viruses. The Arabidopsis mosaic virus is most often transmitted by thrips.
2. Periodic use of special preparations to strengthen the plant's immunity, such as "Epin-Extra."
3. Disinfection of garden tools.

Resistant varieties

There are many rose varieties with strong immunity to pathogenic microflora. Choosing these varieties frees gardeners from a significant amount of concerns related to prevention and treatment. Some of these include:

• "Remembrance";
• "Peace";
• "Westerland";
• Leonardo da Vinci
• "Golden Wedding";
• "Amber Queen";
• "Scarlet Queen Elizabeth";
• Glenfiddich
• Arthur Bell
• «Chanelle»;
• "Pierre de Ronsard";
• "Beautiful Britain";
• "Golden Celebration";
• "English Miss";
• "Black Magic";
• "Fragrant Delight";
• William Shakespeare 2000;
• "Anisley Dickson";
• "Jubilee Celebration";
• Fellowship;
• "Augusta Luise";
• Anne Harkness
• "Wishing";
• City of London;
• Abraham Darby;
• "Double Delight";
• The Times Rose;
• "Nostalgie";
• Harvest Fire;
• "Dame Wendi";
• "Flammentanz";
• "Apricola";
• Queen Elizabeth
• "Cherry Girl";
• "Jubile du Prince de Monaco";
• "Golden Years";
• Aspirin Rose;
• Margaret Merril;
• Crimson Meidiland;
• "Valentine Heart";
• "Escimo";
• Oranges and Lemons
• «Toprose»;
• Chippendale
• "Corresia";
• Chatsworth
• "Princess Alexandra of Kent".

Treatment and prevention of pests

The most important thing in fighting any pest is to detect the infestation early, which increases the chances of a successful treatment outcome. Therefore, it is recommended to regularly inspect rose bushes and take immediate action if insects are detected.

Spider mite

When treating rose bushes against spider mites, it should be taken into account that the majority of pests hide on the underside of the leaves.

Chemicals suitable for spraying roses include acaricides such as Neoron, Actellic, Antikleshch, Vertimek, and Borneo. Flowerbed soil can be treated with iodine-containing products such as Farmaiod or Povidone-iodine.

Folk remedies:

• Soapy solution. Dissolve 1/2 bar of laundry or tar soap in 5 liters of hot water. Rather than spraying, it's best to wipe the leaves and stems of the roses with the soapy solution, removing the mites mechanically as well.
• Garlic. Crush the garlic cloves thoroughly to release their juices and add them to the solution at a rate of 200 g per liter (usually a small volume is prepared, as the tincture is used as a concentrate). Let the garlic steep for 5 days, then strain and dilute 60 ml (4 tablespoons) of the solution in a bucket of water. To dilute the garlic infusion, you can mix the water with a 50/50 dill infusion; this increases the effectiveness of the infusion. To prepare the infusion, pour 5 liters of boiling water over 500 g of dill leaves and let steep for 3 hours.

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• Onion. To combat spider mites, use onion peels: 30 grams of onion peel should be steeped in 5 liters of warm water. Let it steep for 5 hours, then strain.
• Marigolds. Place the dried flowers in a bucket and cover with warm water, ensuring the flowers are submerged. Let the infusion sit for two days, then strain and use to treat shrubs and water the soil.

The bushes are treated with folk remedies 3 times with breaks of 5-7 days.

Spider mite prevention:

1. Adequate irrigation. Spider mites dislike humidity, so they often attack under-watered plants. In this case, sprinkler irrigation is helpful.
2. Plant pest-repellent crops in the flowerbed. Ornamental plants include chrysanthemum and calendula. Basil or dill can also be added to the flowerbed arrangement.
3. Proper nutrition. Adequate phosphorus in the soil prevents spider mites. Conversely, excess nitrogen encourages the pest.

Aphid

Spraying plants with a jet of water can be very effective in killing aphids. Insects that fall to the ground are generally unable to return to the plant and die.

The most effective insecticides for treatment are Kinmiks, Decis Profi, Biotlin, and Aktara. However, chemicals destroy the flower's aroma and make the petals unsuitable for culinary and cosmetic purposes. A more gentle approach is to use bioinsecticides such as Fitoverm, Akarin, and Aktofit. In both cases, three treatments are carried out on the bushes, separated by seven days.

Folk remedies are also effective if applied several times per season (once a week). Effective options:

1. Vinegar. Add 150 ml of 9% vinegar or 450 ml of 3% vinegar to 10 liters of water. Do not spray young shoots or buds with this solution.
2. Tomato and garlic infusion. Pour 300 g of crushed garlic cloves (can be substituted with a similar amount of onion) and 400 g of chopped tomato leaves into 3 liters of water. After steeping for 7-8 hours and straining, add 7 liters of water and dissolve 1/5 of a bar of laundry soap in it.
3. Milk whey. Used to treat delicate areas of the rose bush—young leaves and buds. Apply the product undiluted.
4. Potato infusion. Chop fresh potato tops and pour boiling water over them (1 kg of tops per bucket of water). Let the mixture steep for 2 days, then strain and add 50 g of soap shavings.

In addition to the usual sanitary measures that prevent the appearance of many pests and pathogens, the following is recommended for aphid prevention:

1. Destroying anthills on your property. The insects favor the pest because they feed on the honeydew excreted by aphids.
2. Planting aphids-repelling plants in a rose bed is also an option. Ornamental plants that can enhance the flowerbed include lavender, nasturtium, calendula, fennel, Dalmatian chamomile, and scented pelargonium.

Rose scale insect

The shoots where the pest has taken up residence should be cut off and burned. Afterward, treat the plants with systemic insecticides that penetrate plant tissue, as contact insecticides will not harm the insect, which is protected by a waxy shell. Suitable products in this case include Aktara, Bankol, and malathion-based products (Fufanon, Karbofos).

Four to five days after chemical treatment, the bushes should be sprayed with folk remedies. These treatments should be repeated several times at intervals of 5 to 7 days.

Folk remedies against scale insects:

1. From capsicum. Chop 0.5 kg of fresh peppers, steep them in 5 liters of boiling water, and simmer for about 5 minutes. After cooling and straining, the infusion is ready to use.
2. Tobacco. 2-3 kg of fresh tobacco leaves should be crushed and poured into a bucket of water. The infusion should be boiled for 30 minutes, then left for 2 days.
3. From celandine. 3-4 kg of chopped celandine should be poured into a bucket of hot water and left covered for 24 hours. Then boil for half an hour and strain.

To prevent rose scale insects:

1. Avoid planting rose bushes near other pest-vulnerable crops, such as raspberries, blackberries, and strawberries. If insects appear, preventative treatment should be carried out on all susceptible plants. Wild rose bushes, if present, should be removed.
2. Avoid overfeeding rose bushes with nitrogen.
3. Every six months, support plants with immune boosters, such as "HB-101" and "Obereg."
4. Provide roses with adequate potassium nutrition. In unfavorable conditions or plant depletion, additional foliar feeding with potassium sulfate is necessary.

Nematode

There are no effective methods for controlling this pest. The focus should be on stopping the spread of nematodes. Affected bushes should be dug up and destroyed (burned), and the soil in which they were growing should be generously doused with boiling water. After the onset of cold weather, the soil should be dug over to a depth of a spade to ensure that any remaining pests freeze out.

Gardeners' reviews

Marina, 36 years old:

"It's helpful to add 300 ml of pure alcohol per bucket of solution to herbal infusions for spraying bushes against spider mites. This will increase the effectiveness of the solution. Alcohol works best against spider mites, but it can also be used against scale insects—the alcohol dissolves the pest's "shield," making them vulnerable to contact treatments. We do it this way: first, soak the bushes in the alcohol solution, and the next day, spray with an insecticide. This allows you to reduce the number of chemical treatments from the recommended three to one, but after a short break, you should continue spraying with "folk" remedies. Alcohol can also be used separately to kill spider mites. It destroys larvae and eggs, eliminating the need to repeat chemical treatments (these are usually aimed at the "second generation"). Less chemicals means less harm to the roses."

Natalia, 44 years old:

Everyone knows about the benefits of ladybugs and lacewings in aphid control and prevention, but not everyone knows how to attract them to their garden. These insects love plants with yellow and orange flowers (such as calendula, marigolds, tansy, and sweet clover), and also prefer umbelliferous plants like carrots, fennel, and dill. These attractive plants should be scattered throughout the garden, including in flower beds. Another beneficial and lesser-known insect is the earwig. It likes to nest in sawdust. You can place a few boxes of sawdust in the flower bed.

Margarita, 32 years old:

"There's an interesting recipe for a decoction against spider mites that works. It's impractical because it requires cyclamen tubers, but in severe cases, if you really don't want to resort to chemicals, you can try it—it works great. I use about 100 grams of tubers per liter of water, cut them into cubes, and boil them for 40-50 minutes. I let them steep for 24 hours. The remedy is ready."

Whatever the cause of yellow leaves on a garden rose, if it occurs in the second half of summer, it's important to carefully prepare the affected plant for winter. Weakened roses are not only vulnerable to diseases and pests but also lose their resistance to low temperatures. Support the bushes with immunomodulators and potassium-rich nutrients.