Why My Hydrangea Leaves Turning Yellow

Hydrangeas are a delightful addition to any garden. These shrubs produce large clusters of flowers, adding vibrant color and texture throughout the season.

Unfortunately, many gardeners experience yellowing leaves in their hydrangea plants. This is usually caused by one of several underlying issues.

To help diagnose the cause of yellowing leaves on your hydrangea plant, it’s important to understand what factors contribute to optimal health and growth. Common causes include nutrient deficiencies such as iron or nitrogen; environmental stressors like too much sun exposure; pests such as aphids or mites; diseases like fungal infections; and poor soil drainage leading to root rot.

Knowing which issue is causing your particular problem will enable you to take corrective action before serious damage occurs.

Hydrangea Leaves Turning Yellow

Improper Watering

Hydrangeas are finicky plants that require an exact balance of water and sunlight to remain healthy. Improper watering can cause hydrangea leaves to turn yellow, a sign of distress in the plant.

The process for proper watering is relatively simple: consistently moisten the soil around the roots while avoiding overwatering or underwatering. During periods of extreme heat, it may be necessary to water every day; during cooler weather, less frequent but more thorough dousings should suffice.

It’s important never to let the soil dry out completely as this will quickly lead to wilting and leaf-yellowing. If you suspect your hydrangea has been underwatered, try giving it a deep soak and then monitor its health closely over subsequent days.

Too Much Sunlight

Hydrangeas are popular garden plants, known for their colorful blooms and easy maintenance. However, one common problem with hydrangeas is the yellowing of leaves which can be caused by excessive sunlight exposure.

Too much direct sunlight causes a decrease in chlorophyll production resulting in a weakened plant that has less green pigmentation in its foliage. In addition to decreased photosynthesis, too much sunlight also increases the risk of sunburn on the tender new growth of hydrangea bushes.

To prevent further damage from occurring it’s best to keep your hydrangea out of direct sunlight during peak hours or move them to an area with partial shade where they will have more protection from the intense rays of the sun.

Lack Of Nutrients

Yellowing of hydrangea leaves is usually a sign of inadequate amounts of essential nutrients. In particular, nitrogen and phosphorus deficiencies are common causes.

Nitrogen deficient hydrangeas have yellowed lower leaves but the veins remain green; this condition can be corrected by supplementing with an appropriate fertilizer that contains nitrogen at recommended levels.

On the other hand, phosphorus deficiency will result in older or lower leaves turning purple-brown while younger leaves appear only slightly affected; treatment calls for adding proper phosphate fertilizer according to package directions.

Disease Or Pests

Diseases and pests can cause hydrangea leaves to turn yellow, resulting in a significant decrease in the overall health of the shrub.

Diseases are typically caused by overly moist or humid conditions that lead to fungal growth which in turn causes yellowing of foliage. Common diseases include powdery mildew, bacterial wilt, leaf spots, rust, and root rots.

Pests such as aphids, slugs, caterpillars, and mealy bugs may also feed on hydrangeas causing them to become sickly and subsequently resulting in yellowed leaves.

To identify if this is indeed the case look for common signs associated with these pests:

  • Aphids – small soft-bodied insects that suck sap from stems and undersides of leaves; often leaving behind honeydew which can result in sooty mold development.
  • Slugs – slimy trail left along soil surface or under leaves.
  • Caterpillars – chewed holes in the foliage.
  • Mealybugs – white woolly masses found around joints of stems and under leaves.

To ensure successful maintenance of your hydrangea it is important to monitor plant health regularly. If disease or pest infestation is suspected then appropriate action should be taken immediately to prevent further damage.

Prevention techniques such as selecting resistant varieties when planting new shrubs, pruning out dead wood carefully, and avoiding overhead watering can help reduce the risk of infection.


Over-fertilizing is a common cause of hydrangea leaves turning yellow. Too much nitrogen, phosphorus, and potassium can lead to an imbalance in the soil composition which would prevent the plant from receiving the vital nutrients it needs for healthy growth.

In addition, when too much fertilizer has been added to the soil, there may be insufficient calcium or magnesium available to combat chlorosis – a condition that leads to the yellowing of foliage.

When trying to identify if over-fertilization has caused your hydrangeas’ leaves to turn yellow, inspect your garden for signs of damage such as brown patches on the leaves or wilting stems. If these are present then this could indicate that you have used too many fertilizers and should reduce their application in order for the plants to thrive again.

Too Little Sunlight

Having over-fertilized a hydrangea can lead to yellowing of its leaves, but another possible cause for this discoloration is too little sunlight.

As the old adage goes, ‘Too much of anything is bad.’ In other words, plants need balance and moderation in order to thrive. Without adequate sunlight exposure, a plant’s health will suffer and it may start displaying distress signals like pale foliage or wilting.

Hydrangeas are no exception; they prefer bright indirect light throughout the day since the direct sun might scorch them. Therefore, if you notice your hydrangea’s leaves turning yellow, give it some extra sunshine by placing it near an east-facing window or use artificial lighting as an alternative.

With enough light, your hydrangea should return to its beautiful state shortly. However, if none of these solutions help, then cold weather could be the culprit.

Cold Weather

Hydrangeas are one of the most beloved plants in gardens and yards, but when its leaves start to turn yellow it can be a worrying sight. Cold weather is often the culprit for this discoloration as hydrangeas prefer mild climates that avoid large fluctuations in temperature.

In order to protect your hydrangea from cold temperatures you should consider:

  • Planting the shrub near a structure or wall where some additional warmth will be provided during cooler months.
  • Adding mulch around the plant’s base to help keep moisture levels up and regulate soil temperature.
  • Pruning back dead stems and branches after winter has passed so new growth isn’t hindered.
  • Placing an overhead covering over the bush on particularly chilly days.
  • Watering regularly throughout fall and winter to ensure roots remain healthy.

Knowing how best to prepare your garden for colder weather will result in healthier looking hydrangeas come springtime. Unexpected drops in temperature can lead to stress on plants, resulting in leaf discoloration, wilting flowers, and reduced overall health.

Sudden Temperature Changes

Cold weather can cause hydrangea leaves to turn yellow. In fact, one study shows that up to 90% of all gardeners have experienced this issue at least once during the cooler months. The sudden changes in temperature are another factor to consider when diagnosing why a hydrangea’s leaves may be turning yellow.

As temperatures drop and then quickly rise again, it can put stress on the plant which causes chlorosis – the discoloration of the foliage from green to yellow or white due to lack of available iron for photosynthesis. Furthermore, these fluctuations in temperature create an environment where fungal diseases such as powdery mildew and leaf spot can easily form on plants with weakened defenses.

To help protect your plants against these common issues, it is important to keep an eye out for any signs of distress from cold temperatures and make sure they are well-mulched during winter months.

Wrong Soil Ph Level

The yellowing of hydrangea leaves is often a result of incorrect soil pH levels. Hydrangeas prefer acidic soils with a range between 5 and 6, while alkaline soils can cause the foliage to become discolored:

  1. Under an alkaline environment, iron becomes locked in the soil and unavailable for absorption by plant roots.
  2. Iron deficiency causes chlorosis or interveinal chlorosis, which manifests as yellow-green veins on a dark green background.
  3. Without sufficient nutrients from the soil, photosynthesis slows down leading to tissue necrosis or death of leaf margins and eventually entire leaves turn yellow and drop off.
  4. If the affected area has been over watered, root rot may occur resulting in further damage to plants’ health and development due to lack of oxygen supply around roots.

These signs are good indicators that it’s time to act quickly – by adjusting the level of acidity or alkalinity – if you want your hydrangeas looking their best again.

Too Much Shade

Hydrangeas are known for their beautiful and varied foliage, however, when the leaves turn yellow it can be an indication of too much shade.

Too much shade for hydrangea plants is caused by either not enough sunlight or a location that has heavy tree cover. When there isn’t enough sun, the plant will begin to struggle with photosynthesis which means it won’t be able to absorb nutrients from the soil as efficiently, resulting in decreased growth and yellowing leaves.

It is important to ensure that your hydrangea gets at least 4-6 hours of direct sunlight per day if you want it to thrive. It can also be difficult to determine if the amount of shade on your hydrangea is too much because all varieties have different light requirements; some may need more light than others.

To prevent this issue, make sure you research what kind of light levels are needed for your specific type of plant before planting it in any location. Taking these precautions will help ensure that your hydrangea stays healthy and happy in its environment. With the right amount of sunshine and attention, you can enjoy vibrant blooms year after year.

Should You Cut Off Yellow Leaves?

In considering the question of whether yellow leaves should be cut off, it is important to understand why hydrangea leaves are turning yellow in the first place.

It may be a sign of nutrient deficiency or disease, and cutting off affected foliage can help improve the health of your shrub. However, there may also be cases where the yellowing of the foliage is simply due to environmental conditions that are outside of one’s control.

Therefore, taking into account both potential causes for leaf discoloration, professional horticulturists recommend assessing each individual case before attempting any drastic actions such as pruning.

By doing so you will avoid exacerbating any existing problems and better ensure healthy growth for your hydrangea plants in the long run.

Why Do Different Species Of Hydrangeas Leaves Turn Yellow?

The sight of yellowing hydrangea leaves can be a worrying one for any gardener. The beauty they bring to the garden is soon replaced by an uninviting shade of pale, sickly yellow that can spread quickly throughout the bush.

Hydrangeas offer many different varieties and colors, each with its own unique characteristics when it comes to leaf discoloration. Depending on the species, there are several reasons why their foliage may become stained or fall off prematurely.

In some cases, under-watering or too much direct sunlight may cause the leaves to turn yellow due to dehydration or sunburned foliage respectively. Fungal diseases such as powdery mildew or rust can also lead to discolored leaves while pests like aphids or scales feed on sap and leave behind honeydew which encourages sooty mold growth leading to further damage in affected areas.

Imbalanced soil nutrition may also play a role in this process where excess nitrogen causes chlorophyll breakdown resulting in lighter colored foliage. Additionally, environmental stress during periods of extreme heat or cold has been known to cause yellowish patches on some types of hydrangeas.

Knowing how these factors affect particular species is key for successful prevention and control measures when dealing with wilting and discolored leaved plants. In order to maintain healthy plants and beautiful blooms, prudent choices must be made when choosing a location, planting time, fertilizer type and quantity as well as irrigation frequency and duration among other cultural practices specific to each variety of hydrangea grown in home gardens.