11 Hydrangea Care Myths Gardeners Shouldn’t Ignore

Are you confused by some of the gardening advice you get each season with your hydrangeas? In this article, gardening expert and hydrangea enthusiast Jill Drago takes you through some of the most common hydrangea care myths you'll encounter while growing them in your garden.

Pink and Purple Hydrangeas Blooming in Garden

Hydrangeas are known and loved for being stunning low-maintenance shrubs. Their flowers grace our gardens all summer long, making our yards look like a dream!

Whether you are a new hydrangea grower or a seasoned veteran, it is all too easy to look up some gardening tricks on the internet. While the internet is a wonderful place to gain information, you need to take it with a grain of salt sometimes and keep in mind your specific plant and its specific growing conditions.

It is easy to get caught up in wanting to take the best care of your hydrangeas. I get it. However, I encourage you to tread lightly when you are trying out new tips and tricks. Let’s bust some of these pesky internet myths and get back to basics when it comes to caring for our beautiful shrubs!

Myth 1: Fertilizing Always Makes Bigger Blooms

Gardener is putting potting soil with fertilizer around the base of a plant. The plant is a small shrub with pink flowers and some flowers are green.
Fertilizing can help, but too much can also hinder bloom production.

Myth: If you want bigger blooms, pump your hydrangeas with more fertilizer!

Fact: Adding more fertilizer can be detrimental if it is not truly needed. Hydrangeas do not typically need a lot of extra fertilizer if they are planted in good soil. In fact, too much fertilizer can lessen the number of blooms.

Typical garden fertilizer will promote vegetative growth, which is excellent! However, if it is overused, the plant will not have the nutrients it needs to produce beautiful flowers.

If you want to strengthen your bloom, you can use a high-phosphorus fertilizer. This will not make your flowers bigger in size, but you may see more flowers throughout your shrub.

The best way to have beautiful blossoms is by making sure your hydrangea is in good overall health. Remove dead, damaged, or diseased plant material. Keep the plant watered, but do not drown the roots.

Ensure the plant is getting enough sun which is crucial to the production of flowers. Other than panicle hydrangeas which love full sun, other species thrive in partial sun with about 4 hours of morning sunlight.

Myth 2: You Should Always Deadhead

Gardener is deadheading green flowers blossoming off a shrub. The flowers are green and so is the foliage.
Despite popular belief, you don’t always need to deadhead.

Myth: If you want your hydrangea to bloom all summer, you should deadhead fading flowers.

Fact: Deadheading your hydrangeas will not promote more blooms. Most hydrangea shrubs only produce one large bloom per season.

However, there are some reblooming varieties. These varieties bloom on both old wood and new wood, which lengthens the bloom period.

If you deadhead your flowers, your hydrangea will not produce new ones that season. There are some benefits to deadheading your shrubs, however.

You can use the spent blossoms, or nearly spent blossoms, indoors in fresh or dried arrangements. Deadheading throughout the season will help minimize your fall clean-up work.

Remember, removing your spent flowers is not necessary. The dried blossoms provide pretty winter interest in your garden when everything else has gone dormant.

Myth 3: Changing Bloom Colors is Difficult

Shrubs are blooming in season and are changing color. The flowers are blue and changing to pink which leaves them a shade of purple in between during the transition.
Changing flower colors is as easy as changing the pH of the soil.

Myth: Changing the color of your hydrangea flowers is difficult to do by yourself and should not be attempted at home.

Fact: This myth could not be less true. There are many products available at your garden center that will help you to easily alter the pH of your soil, hence altering your flower color.

None of these products should be applied until you have done a soil test, though. This will help you determine how much of a product you need to use, if any at all!

Once you have your soil test results, you can decide if you need to make your soil more acidic for blue flowers or more alkaline for pink flowers. Anything less than 6.5 is considered to be acidic soil, and anything above 7.5 is considered to be alkaline.

Myth 4: Using Household Items Will Change Bloom Colors

Gardener dumping coffee grounds to the base of a plant. The coffee grounds are used and being put in the soil to increase the acidity levels.
Household items can cause more damage than actual benefit to your plants.

Myth: You can easily change the color of your flowers by using coffee grounds, rusty nails, or pennies.

Fact: I wish these rumors were as true as the next gardener, but sadly they are not. In fact, using these objects can cause harm to your plant. Coffee grounds, if used too heavily, can damage your soil structure.

The hardened coffee grounds make it very difficult for water to permeate through the soil, hence making it nearly impossible for your hydrangeas to take up any water. 

If you are looking to turn your flowers blue, your best bet is to use a soil acidifier that can be purchased from your local garden center.

Myth 5: Flower Colors Can be Changed on All Species

Flowers that are changing color based on the PH adjustment of the soil. The flowers are pink, purple and blue.
Not all species can change their bloom colors.

Myth: No matter what color your hydrangea is, you can alter its color!

Fact: Unfortunately, this just is not true. The only species that can change its flower color is Hydrangea macrophylla or bigleaf hydrangea.

The flowers within this species can range from red, blue, pink, purple, or white. Many of these can be altered from blue to pink, pink to blue, or any shade in between. However, if you start with a white hydrangea, it will always be white.

Myth 6: You Have to Prune Every Year

Gardener pruning a shrub at the base of a spent bloom. They are using a pair of pruners with green plastic handles. The flower they are cutting off is brown and dying.
Not all species require pruning every year.

Myth: Hydrangeas need to be pruned every year to produce flowers and healthy foliage.

Fact: Not only do they not need to be pruned every year, but they also may never need to be pruned at all! Pruning is not necessary to improve the performance of any species.

Pruning can help to strengthen your hydrangeas stems which can come in handy in species or varieties with larger blooms, such as smooth hydrangeas. Varieties such as ‘Annabelle’ have such heavy flowers that their stems can become weighed down and droop toward the ground.

When it comes to planting, the best practice is to choose a location in your garden that is suited for the full size of the plant. This will help to prevent any unnecessary pruning while also allowing the shrub to grow to its true shape.

Something you can do every year is pruning out the deadwood. You can find the dead stems easily when the leaves have dropped.

These stems are woodier than the rest and are often hollow. You can cut them right to the ground. In some instances, you can just pull them out with your hand.

Myth 7: Only Prune During Spring

Gardener pruning shrub in the springtime with pruning shears. The gardener is wearing rubber gloves, and using pruning shears that have green rubber at the bottom of them.
Some species can be pruned in spring, while others can be pruned year-round.

Myth: The best time of the year to prune is in the springtime before you notice any leaves growing.

Fact: If you are growing a hydrangea that blooms on new wood, you are free to prune whenever you want. However, if you are growing a species that blooms on old wood, pruning in the spring will remove your blossoms immediately.

Old wood-blooming hydrangeas typically do not require any pruning at all. They have a nice size and shape. If you have planted them in a space that can maintain their full size, you will only need to prune away the dead wood, and damaged branches. Or for aesthetic purposes, if you want the perfect shape.

Regardless of why you choose to prune your old wood hydrangeas, this is best done right after they finish blooming in the late summer or early fall.

Shrubs that bloom on new wood can be pruned in the fall or in the spring. You can take the branches down to about a foot in height in the fall.

You could leave all of the stalks for winter interest. When spring arrives, you can take all of the stalks down, leave a few for support of new growth, or leave them all intact!

Myth 8: You Only Need Basic Fertilizer

Gardener is mixing in fertilizer with dark soil, The gardener is wearing a white glove and mixing it all together.
Using a specific ratio of nitrogen, phosphorus, and potassium in your fertilizer are essential.

Myth: Hydrangeas are so incredibly low maintenance that using a basic fertilizer will produce beautiful blooms.

Fact: Hydrangeas are low-maintenance plants that may not require any fertilizer from you at all. Using compost is a great way to give them a nutrition boost.

If you want to use a chemical fertilizer, there are plenty of great options. 10-10-10 fertilizer is a great product that can be used across most of your gardens, including hydrangeas. You may run into trouble with their blooms if you overuse this fertilizer, however.

The numbers 10-10-10 represent the ratio of nitrogen, phosphorus, and potassium, or N-P-K, in the fertilizer. Phosphorus, the middle number, is the element that they need to produce their beautiful blossoms.

If a hydrangea gets too much nitrogen, it will produce beautiful green foliage, but it will be lacking in the flower department. If they are planted near your lawn, the roots may be taking up nutrients from your lawn fertilizer as well.

Before you choose a fertilizer product, it is always a great idea to get a soil test to see if you even need to supplement any nutrients. More often than not, compost will do the trick.

Myth 9: You Can’t Overwater

Gardener pouring water out of a watering can onto flowering shrubs. The flowers are blue, pink, and light purple.
You’ll want to avoid overwatering your plants to prevent disease.

Myth: Hydrangeas are water lovers, and no amount of water could be too much for these shrubs. Their name starts with hydra- which means water!

Fact: Yes, hydrangeas indeed love water. But just like anything, they have their limits. The amount of water that your hydrangeas require will differ from species to species, depending on where it’s planted. On average, most species require one inch of water per week. This can be monitored by using a rain gauge.

Hydrangeas hate having wet feet. If their roots sit in soil that is not well draining, your plant could be in trouble. Root rot sets in quickly when roots sit in soggy soil.

Fungus is also much more present in shady and wet areas, opening hydrangeas up to fungal diseases which can cause harm to your plant.

Other issues can arise with your plant aside from disease. You may notice that your flower production is low and growth has been stunted. Too much water in the soil can cause the yellowing of leaves due to the shrub not being able to take up enough needed nutrients.

Myth 10: Only Plant Them in the Shade

Blue flowering shrub is growing in the shade. There are small clusters of blueish purple flowers blooming all over the plant. Green foliage is at the base in the background.
While some varieties grow well in the shade, others prefer a sunnier environment.

Myth: Hydrangeas are lovers of deep shade and grow best in these conditions. Planting in the sun will scorch the leaves.

Fact: Some hydrangeas do love shade, and others love to grow in full sun. However, no hydrangeas thrive in full shade. They need sunlight for photosynthesis. They also need the sunlight to produce strong stems, as well as large and plentiful flowers.

If you are not sure how much sunlight a specific part of your garden gets, you can use a sunlight monitor or you can go out and check the spot every hour for a day or two.

Hydrangeas are susceptible to fungal diseases which are plentiful in the shade. Without adequate time for the plant surface to dry out in the sun, the fungus will have an easier time taking hold and damaging your plant. 

Hydrangea paniculata thrives in full sun and will grow best with 6-8 hours of sunlight.

Hydrangea macrophylla, anomala, serrata, arborescens, and quercifolia do best in the partial sun, which is around 4 hours of sunlight. These shrubs should get their sunlight in the morning to help prevent too much water loss in the hot afternoon hours.

Myth 11: Avoid Planting in Containers

Beautiful purple blooming plants growing in container outdoors. The shrubs have purple blooms with some yellow at the center.
Despite popular belief, hydrangeas make wonderful container plants.

Myth: Planting hydrangeas in pots is difficult due to their size. It also poses a challenge when it comes to overwintering.

Fact: Hydrangeas make wonderful potted plants. Planting them in large containers can allow many people the opportunity to grow these beautiful shrubs if they do not have the space or the correct growing conditions.

It is very simple to grow hydrangeas in containers, and there are so many varieties that will grow nicely for you. From dwarf varieties to larger varieties, whatever your growing needs are, there is a hydrangea for you. You may even opt to grow them as an annual and choose not to overwinter your shrubs.

You will want to start with a large container. If you plan to overwinter, you will want to make sure this pot is at least twice the size of the root ball.

This will give the hydrangea room to grow. Use potting soil to fill your plants, or at least a mixture of garden soil and potting soil This will keep the container light enough for you to move around. The potting soil will typically have some fertilizer pre-mixed in, which will help give your shrubs a little boost.

Depending on what variety you have chosen to grow, you will want to find the perfect location for your newly planted container. Panicles love the full sun, while the rest benefit from the partial shade of the morning sun.

Be sure to check these pots daily for water. They will not have as much water available to them as those that are planted in the ground.

Final Thoughts

When it comes to debunking gardening myths, go with your gut. If you have a good knowledge of your plant, you will be able to easily learn the proper care for your hydrangeas. While at-home tricks are fun to test out, they usually don’t pan out in the long run.

We all know and love hydrangeas for their beautiful blossoms, but they truly are low maintenance, and this adds to the plant’s allure. Try not to overthink your hydrangea care and focus on the basics.

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