What Makes Hydrangeas Turn Purple

This traditional favorite is a must-have in any garden, and new cultivars have made hydrangea cultivation simpler than ever.

Generally speaking, blue or lavender-blue hydrangea flowers are produced by acidic soil, which has a pH lower than 6.0. Pinks and reds are encouraged by alkaline soil, which has a pH above 7.0. The blossoms turn purple or bluish-pink at a pH of 6 to 7.

Add aluminum sulfate or garden sulfur to your soil to reduce pH levels. Use ground lime to increase the pH. To ensure that the pH of your soil is within the desired range, retest it according to the instructions on the product you’re using.

Fungal Disease

Cercospora leaf spot, a prevalent leaf fungus in these plants, can be identified by the presence of purple dots on hydrangea leaves. Although spotted leaves can shed early, weakening the plant and limiting the number of viable buds, plants are rarely killed. Usually beginning at the plant’s base, the tiny purple to brown patches grow outward and upward when water splashes the spores onto adjacent leaves. The type of hydrangea involved determines the specific spotting patterns.

By removing fallen leaves and hydrating your hydrangea at the base, you can stop cercospora from spreading. In a densely packed hydrangea bush, opening the canopy by pruning up to one-third of the branches will improve air circulation and hinder the spores’ ability to germinate. Azoxystrobin, chlorothalonil, mancozeb, myclobutanil, or thiophanate-methyl should be used at intervals of 14 days if cercospora is severe and pervasive.

Phosphorus Deficiency

When hydrangea leaves become purple, the plant may be trying to notify you that there isn’t enough phosphorus in the area to support it. In their haste to alter the hue of their hydrangeas’ flowers, gardeners occasionally unintentionally cause the pH to go so low that other chemical substances bind phosphorus. The inability of bound phosphorus to be utilized by plants deprives them of essential nutrients.

Examine your soil. Alkali soils with pH levels above 7.0 may bind phosphorus with calcium or magnesium, while acidic soils with pH levels below 6.0 frequently allow aluminum to bind the element. The initial step in releasing phosphorus from your soil is to adjust the pH, but if this doesn’t work after a few weeks, you’ll need to fertilize your hydrangea with phosphorus.

Weather’s Influence

The color of hydrangea leaves can also be affected by the weather, resulting in extensive purple discolouration. When the growing season is about to finish, cool conditions may cause the plant to go into dormancy early, allowing the purple color of the leaves to emerge as the green chlorophyll factories stop producing them for the year.

Purple discolouration might also result from frost damage. When the leaves are dry, remove the severely harmed ones, but keep the somewhat harmed ones until new leaves emerge.

What can you use to dye hydrangeas purple?

Grow your plant in its current soil for a year to allow it to reveal its “true colors.” If the blossoms are a deep blue color, your soil likely contains aluminum and is acidic. Simply adding lime and phosphate to the soil will result in purple flowers. By doing this in the fall, you can change the colors for the upcoming growing season. Make a note of how much lime you used so you can later change the colour to your preference.

If the blossoms are pink, test the soil to find out how much aluminum is present and the pH of the soil. If there is a lot of metal in the soil but a high pH, add organic compost to lower the pH. The color will shift toward blue as a result.

It makes no difference whether the pH is high or low if the soil lacks aluminum because the process for altering bloom color is the same. The soil has to be amended with aluminum sulfate. Aluminum is also added as the soil is acidified. Over multiple growing seasons, you’ll need to experiment with the amount you administer to bring the blossoms to your desired shade of purple.

How are blue or purple hydrangeas maintained?

Although most plants may grow in a variety of soils, others require particular kinds of soil to thrive. Rhododendrons, azaleas, and other ericaceous plants require acidic soils in order to thrive. The soil in your garden must be acidic if they flourish there or in the gardens nearby. Rhododendron leaves turning yellow or disappearing from the area indicate that your soil is likely alkaline. In addition to affecting what you may grow, your soil type can also affect some plants’ leaf and blossom colors; hydrangeas are a well-known example.

Some hydrangea cultivars grow pink or red in alkaline soil and blue or purple in acidic soil. Therefore, if you plant a beautiful blue lacecap or mophead hydrangea in your garden and your soil is neutral to acidic, it will continue to produce blue flowers every year. Even if it was clear blue when you got it, it will flower purple-red or pink if you plant it in alkaline soil the next year.

It is challenging to keep beautiful blue blossoms alive in the open ground, but it is doable if you grow it in a pot; hydrangeas make wonderful topics for pots and containers. Select a pot that is attractive and big, at least 40 cm (15 cm) in diameter. Vitax Ericaceous Compost is the best growing medium for it; plant it there. If you consistently feed your hydrangea, it will thrive on this fertilizer that is specifically made for rhododendrons, azaleas, and other lime-hating plants.

Even though the growing medium begins out being free of lime, repeated watering in places with hard water tends to make it more alkaline. Therefore, add Vitax Hydrangea Colourant, a powder containing aluminum that you may mix with the compost, to ensure that your hydrangea stays truly blue. Each spring, you can also incorporate a small amount into the soil’s top layer and add it to the can when watering your plant.

White hydrangeas, incidentally, don’t change color depending on the type of soil, but they can blush pink in the light.

Feeding and watering

In pots, containers, and during dry spells in the open ground, regular watering is necessary since hydrangeas detest dry environments. When you plant your hydrangea in a bed or border, add lots of garden compost or farmyard manure, and make sure to water well both before and after planting.

The presence of food in the soil is necessary for hydrangeas to grow and produce flowers, even if they are not very demanding plants. In the open ground and in pots and containers, Vitax Conifer and Shrub Fertilizer should be used annually. This is ideal for acid-loving plants and won’t change the hydrangea’s color.

Does baking soda like hydrangeas?

Ever wondered what happened to your hydrangeas after going outside to check on them? They frequently appear unexpectedly exhausted and wilting, as if they are close to passing away. Your hydrangeas might even appear to get smaller every year. Here’s how to restore hydrangeas and make them seem gorgeous once more!

Everyday Care of Hydrangeas

Make sure you are familiar with the ideal hydrangea daily maintenance. Both location and a nutrient-rich, well-drained soil are quite important. Never overwater them, and don’t fertilize them too frequently. Read my entire post to learn how to take care of hydrangeas. Get ready for the next phase once you have a firm handle on how to care for your hydrangea plants on a daily basis!

The Secret to Revive Hydrangeas

Your hydrangea bushes can be revived with a top-secret chemical, but I’m going to tell you what it is! Although you’ve probably never heard of it, you already have the secret ingredient in your kitchen. Have you prepared? It’s baking soda, of course!

A Little Goes a Long Way

The key is baking soda, but be aware that a little goes a long way. Mix 1 tablespoon of baking soda with 2 cups of water and use it to revive your hydrangeas that have withered. Make sure the baking soda completely dissolves by stirring. Note: This dose is sufficient for 3–4 hydrangea shrubs.

Every two weeks, apply this baking soda treatment. If you only have one hydrangea plant, you can apply the therapy to other weak plants and still get similar results.

Enjoy Thriving Hydrangeas!

You should start to notice more strong hydrangeas in a week or two. The plants start to produce flowers that are fuller and healthier.

Try baking soda if your hydrangeas just aren’t impressing you like they should. Try baking soda in the rest of your garden while you’re at it as well!

Note from the editor: This article was first published in July 2017. The information has been revised.

Which fertilizer is ideal for hydrangeas?

When purchasing fertilizer, check the labels to see how much nitrogen (N), phosphate (P), and potassium are present (K). A general-purpose, balanced fertilizer such a 10-10-10 N-P-K or 12-4-8 N-P-K is typically best for hydrangeas. Consider using a fertilizer with additional phosphorus if you want your hydrangea blossoms to be bigger and more numerous.

Since phosphorus is the middle element, fertilizer with the formula 10-20-10 will do. Choose a slow-release granular fertilizer with the designation “bloom boost” if you’re looking into it because it might also include more phosphorus.

Can I grow hydrangeas with Miracle Grow?

There is no need to buy expensive plant food. This cost-effective alternative has a 15-30-15 N-P-K composition that encourages more flowers per shrub and colorful flower heads. Including hydrangeas, this all-purpose blossom enhancer can be applied to a large selection of permanent and annual blooming plants.

It offers a variety of minerals, such as iron, copper, and boron, to complement typical dietary deficits. For the biggest, brightest blooms and healthiest plants, the water-soluble formulation should be applied every 7 to 10 days throughout the growing season.

  • Water-soluble fertilizer, type
  • Ratio of NPK: 15-30-15
  • Approximately 1.5 pounds
  • encourages most flowers to bloom more
  • Easily combines in a watering can
  • increases some plants’ size
  • Must be routinely administered and suitably diluted.

Do hydrangeas’ colors alter when coffee grinds are added?

Coffee has always been amazing to me. If not magical, then pretty close. I mean, I’m a writer, and I’m pretty convinced that writers account for at least half of the sales in the coffee industry. But this also means that every day, we throw away tons of used coffee grounds. Although coffee grounds alone are not very harmful to the environment—in fact, I’ll teach you how to use them in your yard in a moment—they do add to the volume of landfills. Coffee, ever the sociable drink, mixes with other trash in foul trash heaps to produce methane, which as we all know is a greenhouse gas that contributes to climate change. So the next time, try something a little different rather than simply throwing the grinds in the trash.

If you just drink one pot of coffee per day, you will have a lot of wonderful, mineral-rich grounds left over after you finish your first pot of the day, which you can use to enhance your garden. We coffee aficionados enjoy the strong coffee fragrance, but insects that harm flowers respond negatively to it. Coffee grounds not only deter ants and snails, but they also stop neighborhood cats from digging in your flowerbeds. Therefore, pile the material high around your preferred plants to ward off slimy, stingy, or fluffy pests.

Use coffee grinds to alter the color of your hydrangeas. The soil around hydrangeas becomes more acidic thanks to coffee grinds. Chemically speaking, the plant can more readily absorb naturally occurring aluminum in the soil as a result of the increased acidity. Pretty blue flower clusters are the result. Coffee grinds let you play with the color to transform pinker blossoms into other shades of blue, or perhaps a shade of purple in between, even if coffee won’t influence the brilliance of the flowers (pale blue flowers will remain pale blue, for example).

Coffee contains nitrogen, which helps plants grow, so give your plants a boost by turning the grinds into a natural fertilizer. Add a quarter cup of coffee grounds to four or five liters of water to make a “tea of coffee grounds.” Pour the liquid over all of your plants the next morning for a nutrient boost after letting it set overnight.

Do hydrangeas turn blue from rusty nails?

In reality, the presence or absence of a rusted nail or other rusting metal in the soil has no effect on how colored hydrangeas are. Many hydrangeas can transform from pink to blue without rusty nails being buried in the plant’s roots.

Can you dye hydrangeas blue with baking soda?

Will hydrangeas’ color be altered by baking soda? One of the simple “tricks” that many people use to alter the color of their flowers is this one. Your hydrangeas’ color and appearance will change if you sprinkle some baking soda in the soil around them.

Can you use banana peels on hydrangeas?

Peels of bananas for hydrangeas Banana peels are an excellent hydrangea fertilizer as well. Per plant, use the peels of two or three bananas. Put the peels around the base of each plant in little piles after being chopped into bits.

Will hydrangeas become blue in vinegar?

In alkaline soil, hydrangea blossoms will be pink; in acidic soil, they will turn blue.

If great French wine is not properly stored, it will turn into vinagre, which we translated into vinegar in English. Vinagre is a combination of the Old French words “vin” (wine) and “aigre” (sour).

There are certain advantages to using vinegar in gardening, especially apple cider vinegar. A few vitamins and minerals are present in apple cider vinegar because it is only fermented apple juice. However, vinegar’s 5% acidity makes it an excellent remedy for any acid-loving plants, including rhododendrons, azaleas, northern bayberries (Myrica pensylvanica), blueberries, and cranberries. Conifers and pecans are two examples of trees that favor acidic soil.

Along with feeding your garden plants, you may use apple cider vinegar on houseplants that prefer acidic soil, such gardenias and camellias. Some houseplants thrive in acidic soil.

You must measure the pH of your soil before fertilizing it or adding any amendments. The soil pH test determines how acidic or alkaline the soil is.

A very acidic pH of 3 corresponds to a very alkaline pH of 10. Seven is regarded as the neutral pH. Your soil’s acidity or alkalinity has an impact on a number of chemical processes, including which nutrients are locked up in the soil and which nutrients are available to your plants.

There are several garden plants that do well in acidic soil, despite the fact that the ideal pH range for most plants is between 5.5 and 7.5. It is not surprising that many plants that thrive near pine trees, such as blueberries, azaleas, and rhododendrons, also prefer acidic soil because pine needles make soil acidic.

The best apple cider vinegar to put on plants is raw, organic apple cider vinegar that hasn’t been filtered. Ensure “with the mother” is written on the label.

The mother is a brown mass that is composed of yeast and bacteria that were left behind during fermentation.

Apple cider vinegar should never be poured directly over plants since it will damage them. Of course, undiluted vinegar will work well if your purpose is to kill plants like weeds in walkways, sidewalks, or driveways.

Use apple cider vinegar diluted with water (20 parts water to 1 part vinegar). Water the plants at the base of them. The vinegar-and-water mixture might burn the leaves, so try to avoid getting it on them.

The ability to transform the color of hydrangea blossoms from pink to blue is another trick apple cider vinegar has up its sleeve. In alkaline soil, hydrangea blossoms will be pink; in acidic soil, they will turn blue.

Give the acid-loving plants a treat by combining apple cider vinegar and water. Or abruptly switch the hue of your hydrangeas from pink to blue. Oh, and what about pearls dissolved in vinegar?

Pearls were dissolved in vinegar and consumed by Cleopatra to display her wealth, likely making the acidic beverage the most expensive beverage ever. Speaking of bittersweet.

Paul Barbano, who lives at Rehoboth Beach, writes about gardening there. You can write to him at PO Box 213 in Lewes, Delaware 19958.