Earlier this year, my hydrangeas’ fresh sprouts burst forth in a vibrant green hue. I decided to sprinkle lime around the root zone in the soil – a move that usually results in pink hydrangeas – and transferred them to larger pots.
However, after a while, the leaves shifted to a shade of red, and the hydrangea blooms seemed to lose some of their color.
Let me share with you the intriguing reasons behind these unexpected changes and the steps you can take to prevent this from happening to your hydrangeas.
Why Did My Hydrangea Leaves Turn Red? Could the red leaves be due to an increase in anthocyanins? And if that’s the case, why did this occur?
Contents
1- Insight from My Local Garden Center
The puzzle began to unravel at the local garden center, where they proposed that the soil’s pH level could be the culprit. While most plants favor acidic soil, pink hydrangeas prefer a slightly alkaline environment.
Adding an excessive amount of lime can make the soil overly alkaline, hindering the plant’s growth and leading to red leaves.
Reverting the soil to its acidic state might help the plant bounce back to its original condition. Proper use of lime in hydrangea soil preparation can be a challenge for novices.
A more reliable method is to plant in acidic soil and gradually adjust the pH with an alkaline fertilizer (if you’re aiming for pink hydrangeas).
2- Guidance from a Plant Specialist
The plant specialist I consulted added another layer to the mystery: apart from the soil’s pH level, the hydrangeas might have suffered stress from disturbed roots, causing them to weaken and the leaves to redden.
Activities as innocent as re-potting or weeding could inflict damage on the roots, depending on the season.
Once the leaves have reddened, they won’t regain their original color within the same year. However, as the roots rejuvenate, the leaves should revert to their typical hue.
The specialist recommended regular watering and applying the appropriate fertilizer three times a month to stimulate new root growth.
Remember, it’s crucial to wait until the plant has fully recovered from transplant shock before fertilizing. After all, healthy root development is essential for your hydrangeas’ thriving growth.
3- Could There be Other Reasons Why Your Hydrangea Leaves are Turning Red?
When a hydrangea falls ill, its entire system can be impacted – from the leaves and flowers to the root system.
If you notice that only the leaf edges are drying out, this might indicate overwatering or a potassium deficiency in the soil.
Additionally, if the soil isn’t acidic enough, your hydrangea may struggle to absorb the vital nutrients it needs to grow. In this case, organic acidifiers can come in handy.
On the flip side, if your hydrangea is receiving too much or too little water or sunlight, you may start to see leaves changing color to brown, black, red, or yellow.
Therefore, when selecting a permanent spot for your hydrangea, consider its specific needs – sufficient but not excessive moisture. Seeing a rust-like discoloration? That could be from harsh sun exposure. Finding a semi-shaded spot under other trees and shrubs can often be the best solution.
If the leaves begin to yellow and fall off, this might be a sign of overwatering, while wilted-looking leaves could indicate inadequate light.
Dried leaves with a rusty hue could suggest a high nitrogen level in the soil. Excessive nitrogen can harm your hydrangea, stimulating succulent-type leaves and new growth, which may attract sap-sucking insects.
This excess nitrogen can also prompt more foliage production than bloom growth, burn delicate young roots, and leave your hydrangea susceptible to root rot and nematode attacks.
Luckily, the solution is simple: add some raw organic matter into the soil to balance the nitrogen levels.
Wilting leaves might be due to drafts. In this case, consider moving the plant and avoid sudden temperature changes.
Yellowing and reddening leaves can also result from insufficient nutrient uptake and low acidity levels. To address this, begin fertilizing three times a month from March until mid-July.
Red Leaves and Fungal Infections Spots and a whitish coating on your hydrangea could be a sign of a fungal disease.
While hydrangeas generally have good immunity against fungal diseases, they can still occur, leading to brownish-red or dark leaf discoloration.
If the leaves first turn black and then develop a white coating, it might be a symptom of root rot, which starts in the root system and can affect the overall appearance of the plant. Using fungicides can help mitigate this issue.
Leaf drying might be due to other factors as well. Brown and reddish spots could be a sign of Septoria leaf spot, characterized by circular spots with darker edges than the center.
These spots can appear on leaves, stems, and cuttings alike. Without timely intervention, the leaves will start to dry and die, threatening the plant’s survival. This disease often shows up in the fall, and applying copper-based solutions can improve the situation.
For the treatment of fungal diseases. Here are the fungicides I recommend:
| Name of The Fungicide | Amount | Amount of Water |
| Bonide 811 Copper 4E Fungicide | 1-4 tablespoons (.05-2.0 fl oz) | 1 gallon of water |
| Garden Safe Brand Fungicide3 | 2 tablespoons (1 fl oz) | 1 gallon of water |
| Southern Ag – Liquid Copper Fungicide | 3-4 tablespoons | 1 gallon of water |
4- Viral Diseases and Their Effects
Have you spotted brown spots tinged with red on your hydrangea? This could signify a viral disease. The effects of such a disease often manifest as curling hydrangea leaves.
Sometimes, the disease can even spread to the flower clusters, a telling sign of the disease’s severity. The bloom might start to wane, producing smaller flowers, or fail to form buds at all.
If these symptoms appear, don’t hesitate until your plant wilts completely or infects nearby plants.
Unfortunately, there’s no cure for leaf spots due to viral infections. Your best course of action is to protect your other plants from becoming infected.
Preventing Red Leaves on Hydrangeas
I’ve covered the possible reasons why hydrangea leaves might dry out or turn red. Yet, the most valuable aid you can provide your plants is preventative care.
Diseases typically affect weak plants, so ensuring proper care is critical to safeguard your hydrangea. Direct sunlight and dry soil can inflict significant damage on your plant.
During hot weather, make sure to water your hydrangea every other day. Furthermore, the soil you choose can contribute to leaf discoloration.
Therefore, it’s important to know what type of soil your hydrangea will flourish in. To protect your hydrangea from various diseases, maintain moist soil and avoid waterlogging.
Many seasoned gardeners believe that hydrangeas with blue flowers are the strongest and least likely to wilt. However, this doesn’t mean that other types of hydrangeas are inherently weak.
All plants need time and meticulous care to meet their needs. With the right care, your hydrangea will blossom abundantly and for an extended period, providing a delightful sight for all to enjoy.