Key Takeaways
- There are several reasons why your hydrangea leaves could be turning yellow, including natural changes, excess water, leaf scorching, lack of nutrients, and fungal or bacterial infections.
- You may need to reduce your watering, use plant treatments, or provide more shade so your plant can thrive.
You feel like you’re doing everything right when it comes to your hydrangea bush—and then the dreaded yellow leaves start to appear right next to your beautiful blooms. It can take a little sleuthing to figure out what exactly is causing your hydrangea’s leaves to turn yellow, but determining the culprit is key to finding the solution.
To help you solve the case, here’s how plant experts suggest troubleshooting yellowing hydrangea leaves—and what you can do, depending on the cause.
What’s Causing Your Hydrangea Leaves to Turn Yellow
As you’re investigating your hydrangea issues, you’ll want to pay attention to where—and how—the yellowing is happening.
Yellowing at the base of the plant
If they’re yellowing just at the base of the plant, it could be leaves that have reached the end of their life cycle and are being shed, Schreiber says. “A few yellowing leaves near the base of the plant can be normal as the plant pulls nutrients from older leaves just before they drop. These older leaves are replaced by new growth higher up on the plant stems.” You’ll see more of the leaves turn yellow during autumn, as the plant goes dormant for the winter.
Yellow leaves at the top of the hydrangea
If they’re at the top of the plant, it’s more likely to be the result of another issue that requires some correction. “Yellow and spotty leaves that are closer to the center and base of the plant tend to be a sign of fungal or bacterial leaf spot, as they prefer to hide in the more humid parts of the plant where conditions are warm and wet,” Schreiber says. In leaf spot, you’ll find the yellow occurs in small spots with green in between or leaves that have a distinct black or red circle on them.
Yellow leaves on hydrangea new growth
Too much water is one of the most common reasons hydrangea leaves yellow—and overwatering or a lack of nutrients may be the most likely culprit if new growth leaves or leaves throughout the plant are impacted. “Hydrangeas prefer consistent moisture but well-draining soil,” Schreiber says. “If standing water builds up in the hydrangea root zone, it can cause the roots to be less efficient and even to rot. This leads to some leaf yellowing and drop as the plant is focusing on trying to repair the roots.”
Yellow or tan splotches on leaves
If the leaves have yellow, tan, or white blotches concentrated on parts of the hydrangea that get a lot of light, the sun could be scorching the leaves. “That means your plant is struggling to manage the intense sun,” Schreiber says.
What to Do About It
Again, this all depends on what the issue is. If it’s simply that the leaves are old or it’s autumn and the leaves are falling off, all you have to do is gather up the old leaves as they fall.
While you don’t have to pull yellowed hydrangea leaves off the plant—unless you want to for aesthetic reasons—it’s smart to clear away the ones that drop to the ground to keep the area sanitary and prevent the spread of any diseases. Note that if your hydrangea’s leaves are yellowing due to nutrient loss, it’s best to allow the leaves to stay on the plant as they may recover.
Correct watering issues
If it’s overwatering, you’ll want to hold off on watering your plant until a few inches of the soil near the roots is dry, then water deeply. But you may need to make more drastic changes in a few instances. “If your area has a lot of rain or a high water table, your hydrangea may need to be put in raised beds or mounds to keep their roots out of the saturated soil,” Schreiber says.
Feed your hydrangea
For a lack of nutrients, you may want to get your soil tested. “Knowing your soil type or getting a soil test done can help you understand what kind of nutrients are lacking in your area and how well the soil holds moisture,” Schreiber says. “Nutrient deficiencies can be corrected by amending the soil.”
Generally, nutrient deficiencies tend to happen in more alkaline soils. “In areas with highly alkaline soils, hydrangeas can struggle to take up iron and other nutrients,” Schreiber says.
Offer more shade, if needed
For scorched leaves, you can either provide more shade for your plant, either with a sun shade or a tree or other plant that will offer it more cover, or you can relocate the plant to a shadier spot.
Keep the plant itself drier
Leaf spot generally will only cause cosmetic damage to your hydrangea, but you’ll want to take corrective action to help keep the plant’s leaves drier. “Watering plants from the base using drip irrigation or a hose on a slow trickle at the base of the plant helps to keep the leaves dry,” Schreiber says. “Avoid watering the plants with overhead spray or using sprinklers that can splash the leaves.”
If your hydrangea bush is thick, it could create pockets in the plant where moisture and leaf spot can thrive. Schreiber recommends keeping the area clean of debris and fallen leaves, and increasing airflow by pruning the canopy as needed to help prevent the growth of bacteria and fungi—though a copper fungicide can also be applied if needed.