By: Jackie Rhoades
Hydrangeas, the glory of summer! These full blooming beauties, once relegated to old-fashioned gardens have enjoyed a well deserved resurgence in popularity. While there are many varieties within the species, the large macrophylla or mopheads are still the most popular. While their normal summer blooming color is blue, pink, or white, we all notice those green hydrangea flowers at some point in the season. Why do hydrangea flowers bloom green? Is there a cause of green hydrangea blooms?
There is a cause of green hydrangea blooms. It’s Mother Nature herself with a little help from the French gardeners who hybridized the original hydrangeas from China. You see, those colorful flowers aren’t petals at all. They’re sepals, the part of the flower that protects the flower bud. Why do hydrangeas bloom green? Because that’s the natural color of the sepals. As the sepals age, the pink, blue, or white pigments are overpowered by the green, so colored hydrangea blossoms often fade to green over time.
Many gardeners believe that color is controlled solely by the availability of aluminum in the soil. Aluminum gives you blue flowers. Bind up the aluminum and you get pink. Right? That’s only part of the story. Those green hydrangea flowers turn color with longer days of light. Light gives those colors the energy to dominate. The color can last for weeks and then you find your hydrangea flowers turning green again. The days are becoming shorter. The blue, pink, and white pigments lose energy and fade away. Once again, green hydrangea flowers reign.
Sometimes you’ll find a hydrangea with green flowers all season long. If you’re new to the garden or the plant is new to you and the plant blooms later than its brethren, you might have a variety called ‘Limelight.’ These relatively new plants have much smaller leaves than the big leaf varieties, although their blooms look similar to the mophead hydrangeas. Flowers turning green is natural to this beauty whose blooms begin and end in white but are bred to be green in between those times.
But if your hydrangea with green flowers is any of the other types and the blooms refuse to change, you’re the victim of one of Mother Nature’s occasional pranks and horticulturalists have no explanation for the condition. It may be a combination of unusual weather conditions, but no scientific reason has been found. Take heart. Your hydrangea with green flowers should only suffer the condition for a season or two before the plant returns to normal.
Why do hydrangeas bloom green? What’s the cause of green hydrangea blooms? They’re interesting questions for the curious, but in the end, does it really matter? If you find your hydrangea flowers turning green, sit back, relax, and enjoy the show. It’s Mother Nature at her best.
This article was last updated on
Read more about Hydrangeas
The plant on the left is ‘Endless Summer’ and the shrub on the right is ‘Penny Mac.’ They both flower on new and old growth but all the flowers you see in this photo were formed last year. The flowers on new wood won’t appear until later in the summer. In between these two shrubs is a fantastic lace-cap: ‘Twist n’ Shout.’
This is the question I hear from frustrated gardeners all over the country. This shrub was supposed to give gardeners in cold regions those same outrageous blue hydrangeas that we love so much on Cape Cod. They are supposed to flower on new growth and be, well, endless right?
Here’s what gardeners in colder regions (zone 5 and below) need to know. Endless Summer does flower on new growth, but most of the flowers are developed on old wood. In late-summer the plant forms the germ of the majority of its flowers for the next year. If you live in an area where the winter temperatures don’t go below 5 degrees Fahrenheit these buds will survive the cold and go on to bloom in mid-summer the following season.
But if you live where the temperatures drop to zero or below, those buds are killed by the cold. In zones 4 or 5 gardeners often find dead canes in the spring instead of stems with green buds. Yes, the plant lives through the winter, but the growth comes back from the ground, not the stems where future flowers were already formed.
The blooming problem can be further compounded by a short growing season. In colder parts of the country the flowers that are formed later in the fall on new growth might not have time to open before the first hard frost. So if you’re gardening in a cold zone 5 or below it’s possible that your Endless Summer might often be an Endless Exasperation.
Don’t get me wrong…I like this plant. There are many Hydrangeas that flower on both new and old wood, and this is one I frequently recommend to my consultation clients because it’s easy to find. But the shrub is just not the flower machine in Minnesota that it is on Cape Cod.
Hydrangea flowers last best when the plant is grown in morning sun and afternoon shade. Don’t let the flowers wilt or they will brown and disappear quickly.
If you want to grow an Endless Summer or one of the other repeat-blooming hydrangeas and you live in a zone 4 or 5, here are some tips for success.
Here at Gardening Know How we get lots of questions, and our goal is to provide answers to those inquiries to the best of our knowledge. Hydrangea plants are a garden favorite offering spectacular beauty to the landscape. That said, they are not without their fair share of problems. The following information includes the 10 most commonly asked questions about hydrangea shrubs.
If your hydrangea isn’t blooming, it’s almost always because it only blooms on old growth. Some varieties bloom on new growth, and these hardly ever cause problems. Old growth varieties, however, can run into a number of issues. If you’ve pruned your plant too much, or if it’s died back to the ground in the winter, it’s not going to bloom this season. The plant is still okay, and it will grow just fine, but all its growth will be vegetative until next summer. The only thing you can do is wait.
Hydrangea pruning varies depending upon the kind of plant you’re growing. There are two major types of hydrangea – those that bloom on old growth and those that bloom on new growth. If your hydrangea blooms on old growth, you should prune it in summer or autumn after it has finished flowering. If it blooms on new growth, you should prune it in late winter or early spring before new buds set. Both kinds of hydrangea benefit from deadheading throughout the growing season to encourage more flower production.
The best time to transplant a hydrangea is in late winter or early spring, when the plant is still dormant. Water your hydrangea thoroughly before moving, then use a shovel or spade to dig a ring around the root ball. You want to get as many roots as possible. Lift the root ball out of the soil and transplant it to a pre-dug hole in its new home. The goal is to keep the roots out of the ground as little as possible. Make sure the soil line is at the same level on the crown of the plant, and water it thoroughly and frequently for the next several weeks.
Many varieties of hydrangea are cold hardy, but they still benefit a lot from winter protection. If your hydrangea blooms on old growth, this is the best time to prune it. Don’t cut it down to the ground, or you won’t get any blossoms in the spring, but you can remove any dead or weak stems and trim the bush to the size you want. Build a protective cage by sinking four wooden stakes into the ground around the plant and wrapping it in chicken wire. Fill the cage with loose material like pine needles or oak leaves to provide a nice insulating layer. If you keep your hydrangeas in pots, the best thing to do is to bring them inside before the first frost.
Hydrangeas do well in pots, as long as they have adequate care. If you’ve received one as a gift, transplant it right away into a pot that’s several inches wider and has good drainage. Give it lots of sun and frequent water. Potted hydrangeas do best if brought indoors for the winter, or at least kept in a protected but unheated garage or shed, where they should be mulched and watered a little once a month. It’s alright if the plant freezes, but best if it stays frozen throughout the winter – lots of thawing and refreezing is bad for the roots.
Hydrangeas almost never produce seeds, which means they need to be propagated from cuttings. In the fall, take a 6-inch cutting of new growth that has no flowers on it. Cut it just below a set of leaves. Remove all but the top two leaves, dip the cut end in rooting hormone, and sink it in damp potting medium. Place a plastic bag over the cutting, put it out of direct sunlight, and keep it moist. New roots and leaves should start to grow in two to four weeks.
It’s not necessary to deadhead hydrangea flowers. But it’s not harmful, either, and it can keep the bushes looking nice. Feel free to remove spent blooms throughout the growing season. It’s important to remember, however, just to cut off the flower head itself. If you cut farther down on the stem, you might be inadvertently removing buds and thwarting your plans for future flowers. Just snip off the spent blooms, taking care to leave the top set of leaves intact.
Hydrangea flowers come in different colors, but those colors are dependent upon soil makeup rather than plant variety. If a hydrangea has blue flowers, this means the soil it’s planted in is high in aluminum or has a low pH. If a hydrangea has pink flowers, it’s planted in soil that is low in aluminum or has a high pH. You should test your soil before making any adjustments if you want to change the hydrangea color. You can turn your hydrangeas blue by lowering the pH, or making the soil more acidic, with the addition of vinegar or an acid fertilizer. You can turn the flowers pink by raising the pH with lime or a phosphorus-heavy fertilizer.
Hydrangeas can be grown in warm climates, but as a rule they don’t like very hot weather. The best way to keep your hydrangeas happy in the heat of summer is to plant them in a spot where they receive some afternoon shade. It’s true that hydrangeas like sun, but not as much as they like keeping cool. They also need lots of water, so you should irrigate them frequently and deeply, especially if they get lots of hot sun. If your summers are hot and moist, space them far apart to encourage airflow and prevent the development of fungus and disease.
Hydrangeas love water (that’s why they have “hydra” in their name. If your hydrangeas are constantly drooping, it’s almost definitely because they’re not getting enough moisture. Hydrangeas should be watered deeply at least once per week. If they’re getting lots of direct sunlight, and especially if they’re in containers, then the watering should be even more frequent. Newly planted hydrangeas also need more water than usual. If you just planted your bushes this summer, make sure to keep their soil nice and moist and put up a shield to protect them from the brightest afternoon sunlight. This should help keep them from drying out and give their roots a chance to grow and find their own moisture.
We all have questions now and then, whether long-time gardeners or those just starting out. So if you have a gardening question, get a gardening answer. We’re always here to help.
Before you prune your hydrangeas, figure out what kinds you have and where the flower buds are formed.
Of all the classes that we offer here at the nursery, pruning is always the most popular. And, of all the different types of plants that need to be pruned, hydrangeas are probably the most confusing. Hopefully, I can help clear the air on how to properly prune these extremely popular shrubs.
Hydrangeas don’t have to be pruned if they are planted in the right location where they can be allowed to grow to a mature size, which can vary depending on the cultivar. For a mature hydrangea, all that is required to keep it looking tidy is to remove the spent flowers sometime before spring.
Most hydrangeas fall into two categories. The most popular flavor is the shade-loving bigleaf or mophead variety that sports large ball-shaped flowers, or the flat and delicate ones called lacecaps. These come in shades of pink to dark purple, plus a few that are pure white.
Traditional varieties of this type of hydrangea should not be pruned, except to remove spent flowers or an occasional errant branch. The reason is that the flower buds are formed on the previous season’s growth — we call that old wood. If you prune those stems back more than a node or two — a node is where a set of leaves was attached — you will remove next year’s flowers.
This is probably the primary reason why hydrangeas don’t bloom. If you have to prune your hydrangea to make it fit into where it is planted, then you will constantly be faced with this dilemma. The solution is to remove your plant and replace it with one of the many new forms that are dwarf and only grow to 3 to 4 feet tall. There is actually a fully dwarf model call “Pia” or “Pink Elf” that only reaches 18 to 24 inches tall.
The second most popular form of hydrangea is the sun-loving panicle type, which has large and fluffy cone-shaped flowers that start out white or lime-green and mature to wonderful shades of pink to rusty red. These hydrangeas bloom on current season growth — we call this new wood — so just like a rose, we can whack the heck out of them if we want to, and they will always reward us with lots of blooms later in the summer.
Again, you don’t have to prune them, but if you do, you will get larger flowers, albeit fewer, than if you just let them go.
Just to confuse the issue, new developments in breeding have brought us repeat-blooming forms (called remontant) of the bigleaf varieties that bloom both on last year’s wood in late spring and again on current season’s wood in late summer.
“Endless Summer” is probably the most recognized brand with its blue plastic pots. The beauty of these new hydrangeas is that if you screw up — or Mother Nature is naughty and freezes off all the buds — you will still get flowers later in the year. That being said, it is still best to keep your pruning to a minimum and focus on only removing spent flowers and a little shaping. Almost all of the new bigleaf varieties now on the market are repeat-blooming and compact growers — which is great news for all of us.
Bottom line, the secret to successful pruning of hydrangeas is to recognize what kind you have and where the flower buds are formed — last year’s wood or current season’s wood. For more info on growing hydrangeas, I highly recommend the Proven Winners website. They have done a very thorough job of demystifying the art of growing hydrangeas. Stay safe and keep on gardening!
By: Dianne Christensen-Herman
Hydrangeas are beautiful, large-leafed flowers that come in a wide variety of colors such as vibrant blues, purples, pinks and whites. These flowers originated in the Japan, but do well in most parts of the world. The color of hydrangeas can be altered by adjusting the pH levels of the soil surrounding the hydrangeas. Anybody can change the color of hydrangeas and all it takes is a little effort to have your white hydrangeas looking their best.
Test the pH level in the soil surrounding the hydrangea. The higher the level, the more acidic it is. Keep the pH level between 6.0 and 6.2.
Add a well-balanced, slow release fertilizer containing equal parts of nitrogen, phosphorous and potassium. Choose a good fertilizer such as 10-10-10 from the store.
Test the pH level again to make sure it is not too high. The pH level should not be above 7.0.
Fertilize the ground surrounding the hydrangea once in late winter. Apply 1 lb. of fertilizer per 100 square feet of soil.
Water regularly with a garden hose, but make sure you don't overdo it or that the water does not stand on the soil. Excess water could cause the plant to wilt and rot. Place 3 to 5 inches of mulch around the base of the plant to protect it. Use shredded wood bark or compost mulch around hydrangeas.
Generally white hydrangeas do not contain pigment and usually do not change color. However, when white hydrangeas get older they can turn blue or pink at the tips. You can try to prevent it by using a well-balanced fertilizer that is low in phosphorous and keeps the acidic levels down. You may need to fertilize in the spring or summer if the soil pH levels need adjusting. Do not try to alter the pH level too much at one time or it could dry out the plant and kill it.
Make sure the hydrangea is in a place where there is morning sun and cool afternoon shade. If it gets too hot and dry the flowers can wilt and turn brown in color.
Do not place a hydrangea under a tree for shade, because the tree will most likely absorb the nutrients and harm the hydrangea.
Hydrangeas are usually some of the first flowers to start looking sad in an arrangement because they have thick, woody stems that produce a sticky sap, which can make it tricky for them to take in enough moisture in a vase to reach the entire flower. But hydrangeas are also one of the few plants that can draw moisture in through their florets, so it's possible to perk up wilted blooms by completely submerging them in water and letting them sit for a few hours to rehydrate.
This trick for reviving cut hydrangeas may not work every time, but it’s worth a shot if you have a few stems you’re not quite ready to toss yet. According to Rizaniño Reyes, a floral designer based in Seattle, the success of this hack depends on a few factors, including “when the flowers were cut and how long they've been in a box in cold storage post-harvest.” You'll probably have better luck reviving slightly wilted fresh-cut hydrangeas, while ones that have been in storage longer might be a lost cause (but still worth a try!). “I've done this with reasonable success, but it's never 100% from my experience,” Reyes says.
Don't be tempted to try this with other common cut flowers like roses, peonies, or tulips to bring them back from the brink of wilting. They don't have the ability to draw in moisture through the blooms like hydrangeas, so soaking them will only make them rot and wilt faster.
They stay white regardless of the soil pH. Okay, here's the trick I promised you. To make soil more acid, sprinkle ½ cup garden sulfur over the soil beneath the hydrangea, and water it in. To make it more alkaline, do the same with ground lime.
Subsequently, question is, how do I get my hydrangeas color back? How to Turn Hydrangeas Pink. To change hydrangea flowers from blue to pink, you need to remove the aluminum from the soil. The only way to do this is to add garden lime to soil to help raise the pH. Sprinkle 3 to 4 cups of garden lime around the base of the plant.
do white hydrangeas turn green?
All hydrangea blooms turn different colors as they age. After the blooms turn green, they may pick up shades of pink and burgundy. Annabelle hydrangeas, which bloom white, ALWAYS turn green when they have been in bloom about two weeks (sometimes they stay white a little longer).
Why are my hydrangeas losing color?
Other causes of faded flower color include the fact that flowers generally fade after pollination. Finally, soil acidity may be responsible for altering or fading flower color. A popular example of this phenomenon occurs with hydrangeas that seem to be particularly sensitive to the amount of acid in the soil.