If you’ve noticed your hydrangea blooms shifting color, you’re not alone. Many gardeners wonder, ‘why are my hydrangeas turning green’ as summer progresses. It’s a common sight that often causes concern, but it’s rarely a sign of poor health. In fact, it’s a perfectly normal part of the life cycle for many hydrangea varieties. Let’s look at what’s really happening in your garden.
Why Are My Hydrangeas Turning Green
The primary reason your hydrangea flowers are turning green is simply aging. The vibrant blue, pink, or white colors you see are actually from specialized leaves called bracts, or sepals. As the flower ages and the reproductive work is done, these colorful bracts often lose their pigment. They then revert to their more basic, leaf-like state, which is green due to chlorophyll. This process is especially pronounced in certain popular types of hydrangeas.
Hydrangea Varieties Most Likely to Turn Green
Not all hydrangeas will show this change equally. The bigleaf hydrangeas (Hydrangea macrophylla), including mophead and lacecap types, are the most famous for this transformation. The classic smooth hydrangea (Hydrangea arborescens), like ‘Annabelle’, also frequently ends the season with green-tinged blooms. If you have these types, seeing green is almost expected by late summer.
The Role of Chlorophyll in Flower Color
Chlorophyll is the molecule that makes plants green and drives photosynthesis. When a hydrangea bloom first opens, the colorful bracts often have very little chlorophyll. Their pink or blue pigments dominate. As the bloom matures, the plant starts producing chlorophyll in these bracts. This helps the aging flower contribute energy back to the plant. It’s a clever bit of plant efficiency, not a flaw.
Environmental Factors That Encourage Greening
- Low Light Conditions: Hydrangeas in deep shade may produce greener blooms from the start, as the plant maximizes chlorophyll to capture limited light.
- Intense Heat of Summer: The peak summer heat can accelerate the aging process, speeding up the color change to green.
- Natural Seasonal Progression: The change is most visable from mid to late summer as days begin to shorten.
Is Green Always About Age? Other Possibilities
While aging is the most common cause, sometimes green blooms can indicate other things. If your blooms are green from the moment they open and stay that way, it could be a characteristic of a specific cultivar, like ‘Limelight’ which is supposed to be green. Rarely, it can be a quirky response to weather or a viral issue, but that’s far less common. Usually, if the plant otherwise looks healthy—with green leaves and strong growth—aging is the clear culprit.
Can You Change Them Back to Pink or Blue?
Once a hydrangea bloom has turned green due to aging, you cannot change it back to its original color. That particular flower has moved on to a new stage. However, understanding what influences color in the first place can help you manage the color of next year’s blooms on varieties where color is pH-sensitive.
- Test Your Soil pH: Use a home test kit. Acidic soil (pH below 6.0) tends to produce blue flowers. Alkaline soil (pH above 7.0) favors pink.
- For Blue Blooms: Apply aluminum sulfate to the soil in spring, following package directions carefully. Adding peat moss or pine needles can also help lower pH.
- For Pink Blooms: Apply garden lime to raise the soil pH. This makes aluminum in the soil less available to the plant.
- Be Patient: Soil amendment is a slow process and may take a full season or more to see a significant shift.
Remember, white hydrangea varieties generally will not change color based on soil pH. They may still turn green with age, though.
Should You Cut Off the Green Flowers?
This is a matter of personal taste. Some gardeners love the vintage, antique look of the green blooms and leave them on the plant. They can add unique texture and color to the late-season garden. Others prefer to deadhead them to keep the plant looking tidy. If you do decide to deadhead, here’s how:
- Use clean, sharp pruners.
- Cut the stem just above the first set of large, healthy leaves below the flower head.
- You can also leave the blooms on through winter; they provide interest and some protection to buds below. Prune them off in early spring instead.
Caring for Your Hydrangeas to Support Healthy Blooms
Proper general care ensures your plant is healthy enough to produce those beautiful blooms in the first place. A stressed plant may have lackluster flowers.
- Watering: Hydrangeas need consistent moisture, especially in the heat. Water deeply at the base 1-3 times per week, rather than frequent light sprinklings.
- Fertilizing: Use a balanced, slow-release fertilizer in early spring. Avoid high-nitrogen fertilizers later in summer, as they can promote leaf growth at the expense of blooms and may contribute to greener flowers.
- Sunlight: Most hydrangeas thrive in morning sun and afternoon shade. Too much deep shade can lead to greener blooms and fewer flowers overall.
Enjoying the Green Stage
The green phase of hydrangeas has it’s own beauty. The blooms take on a deeper, richer hue and often have a longer-lasting, papery texture that is excellent for dried arrangements. To dry them, cut the stems when the blooms feel slightly papery, strip the leaves, and hang them upside down in a dark, dry place for a few weeks. They’ll retain their lovely antique green color for months indoors.
FAQ: Your Hydrangea Color Questions Answered
Do all hydrangea flowers turn green?
No, not all. It’s most common in bigleaf (mophead) and smooth hydrangea varieties. Panicle hydrangeas (like ‘Limelight’) often start green, change to white or pink, then may turn back to greenish-tan. Oakleaf hydrangea blooms typically fade to pink or brown.
Is it bad if my hydrangeas are green?
Almost always, no. It is a natural process. Only be concerned if the plant’s leaves are also showing signs of distress (yellowing, spotting, wilting) alongside the green flowers, which could point to a seperate issue like disease or pests.
Can fertilizer fix green hydrangea flowers?
Fertilizer cannot reverse the green color caused by aging. Using the right fertilizer at the right time (spring) supports overall health for better blooms next year, but won’t change the current year’s aged flowers.
Why are my new blooms opening green?
If brand new blooms are opening green, it could be due to a few factors: the specific cultivar, very shady conditions, or sometimes an excess of nitrogen fertilizer. Evaluate the plant’s location and your care routine.
How long do hydrangeas stay their original color?
This varies by climate and variety, but typically, the vibrant blue, pink, or white color lasts for several weeks to a couple of months in early to mid-summer before the gradual shift to green begins.
So, the next time you ask yourself, ‘why are my hydrangeas turning green,’ you can relax. Your plant is likely just following it’s natural, beautiful lifecycle. This change is a sign of a mature bloom, not an unhealthy plant. Embrace the shifting colors as part of your garden’s seasonal story, from the bright show of early summer to the subtle, sophisticated tones of late season. With the right care and expectations, you can appreciate your hydrangeas in every stage they go through.