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Hydrangea Care – Ultimate Guide to Planting and Growing Hydrangeas

Maintaining hydrangeas will ensure they grow large flowers, and their leaves will be beautiful and green. After a lot of experience with hydrangeas, I decided to write this helpful article explaining how to maintain hydrangeas.

The best way to maintain hydrangeas is to ensure their soil is kept moist. This will allow them to not dry out, which can cause them to grow poorly and even die. You should also ensure they get enough sunlight, but don’t get too hot and dry out.

Some varieties of hydrangeas are hardier than others. There is also an optimum amount of water and sunlight. You should also ensure they are getting enough nutrients in the soil. So, below I will explain how much sunlight they should get, how often you should water them, and how to maintain soil health.

Brief Care Information

Name Hydrangea, Hortensia
Hardiness Zone (USDA) 3-8 (1-12)
Season Spring-Fall
Light Sun, Partial Sun, Shade
Width 2-10 ft
Height 1 ft and more
Pests Aphids, Black vine weevil, Spider mite
Disease fungi, bacteria, viruses
Water In the drought once a week
Soil moist, nutritious

How do I maintain Hydrangeas?

Different types of hydrangeas require different amounts of sunlight and water to remain healthy. Some are hardy and can withstand little to no sunlight and water, whereas others need more water to stay healthy and grow well. Hydrangeas have a hardiness rating, which is on a scale of 1 to 12. They also have sub ratings such as 1a and 1b. It is based on average temperature and weather.

The hardiness rating refers to how hardy a plant needs to be in order to grow well. For example, a plant can have a hardiness rating of 1 to 12. Meaning it will grow well in all of the States in the USA. Most plants will have a more restricted hardiness rating from 3 to 8, for example. This means that it will only grow well in zones that are within these ranges. You can view the hardiness zones for the entire USA as a map here.

Some hydrangeas are very hardy, meaning they will grow well in full shade, and with little water. When looking at buying a hydrangea, you should look at its hardiness rating to see if it is suitable for your area.

This is important because it lets you know how much water and sunlight you should give your hydrangeas. If you live on the of the ends of the range, say, in a state that has a one on the hardiness scale. It means that your State is colder than average. You should plant or keep your hydrangeas in an area where they get more sunlight. You should also take measures to stop frost from killing younger hydrangeas.

If you live in a state that has a hardiness rating of say a 12. Then you should consider watering it more often, as well as planting or keeping it in a place where it won’t get as much sunlight. This is because in higher rating zones, the water that is there will dry out quicker—leading your plant to become dehydrated. You should see what hardiness zone your hydrangeas are in. To assess how much sunlight and water your hydrangeas need.

Inspect plant before buy

A few words, I want to say about how to choose a healthy plant. It often happens that hydrangeas are not appropriately grown, and then there are problems with them.

First of all, inspect the leaves and stems. There should be no spots or holes on them; otherwise, it could mean fungal infections.

There should be no eggs or insect larvae in the middle of the crown and under the leaves. You do not want to bring pests into your garden.

Remove the plant from the pot. The roots should be clean without mold and rot. Also, there should be no traces of insects between the roots.

Most Hydrangeas prefer morning sun and afternoon shade

Most hydrangeas prefer early morning sun, followed by shade in the afternoon. This allows them to get the beneficial nutrients from the sun and gives them the warmth to do their chemical processes. But, too much sun will dry out the plant and soil. Therefore, you should place your hydrangeas in an area where they will be shaded from the West in the afternoon.

This is can be done by placing them to the East of a barrier such as a tree, fence, wall, or house. That way they will get sun in the morning. But, as the sun passes midday, the plant will begin being shaded by the barrier that it is situated next to.

Name Sunlight
Mophead hydrangeas Shade, Partial Sun
Mountain hydrangeas Partial Sun
Panicle hydrangeas Full Sun, Shade
Smooth hydrangeas Partial Sun
Oakleaf hydrangeas Shade, Partial Shade
Climbing hydrangeas Full Sun, Partial Shade

Mophead hydrangeas can grow in the shade and the full sun, depending on the climatic zone. The most favorable hardiness zone for these plants is 5-9. If you live in 8-9 zones, then you should plant these plants in full shade. Otherwise, they will wither. In zone 6-7, plant them in the morning sun, and in the afternoon, there should be shade. In zone 5, Mophead hydrangeas can grow in full sun, but in this case, you should water them more often.

Smooth hydrangeas. 3-9 hardiness zones are the most suitable for growing these plants. No matter where you live, plant them in partial sun. At noon and in the evening, they need shade. Experienced gardeners say that in the Northern States, these plants can tolerate more sun with more frequent watering.

Panicle hydrangeas are the strongest among hydrangeas. They can grow both in full sun and in full shade.

If you live in Hardiness Zone 3-6, then it is better to plant them in the sun. If you plant them in the full shade, then they will have brittle stems and may not bloom. In this climate, they are suitable for full sun or a little shade.

For 7-8 (9) Hardiness zone Panicle hydrangeas, it is recommended to plant in the shade. In hot climates, they feel great in the shade and do not require additional watering. They can also withstand the southern sun, but it will be better if they are slightly shaded.

Oakleaf hydrangea, like the previous species, can tolerate full shade, but only in certain climates. If you live in the south, then full shade would be the best place for this plant. The farther north, the more sun it needs. In a temperate climate, the plant should keep a few hours of the morning sun. The rest of the day, it should be in light shade.

Hydrangea needs a moist and rich substrate

In general, the hydrangea prefers moist soil. Loam will be the best option for growing. This is due to the fact that these plants have many large leaves that evaporate large amounts of water. Therefore, the plant needs to constantly renew the water in the tissues.

Some gardeners say that these plants feel great on heavy clay, but I would still recommend loosening the soil a bit if it is too heavy. This can be done by adding peat, or compost about 10-15%.

If you have heavy soil and high groundwater levels, then you need to arrange drainage under the plant. Hydrangea is a moisture-loving plant but will not grow in the swamp.

On sandy soil that retains little moisture, these plants grow poorly. In summer, when it is hot, the leaves will wither, and you will have to water them more often. To solve this problem, add 20-30% clay and 10-15% compost to your soil and mix well.

As a result, you get a soil mix that will retain moisture well, and thanks to compost, the soil will be more nutritious. The richer the soil, the better the hydrangeas will bloom.

Soil pH Color of flowering
7.0-9.0 (Alcaline) Pink
7.0-6.0 (Neutral) Purple
4.5-6.0 (Acid) Blue

The acidity of the soil directly affects the color of the flowers. If you do not know what the pH of your soil is, then you have two options. First, you can buy a device for measuring soil acidity. The second way is to plant a hydrangea in your yard, and when it blooms, determine what kind of land you have.

In most cases, the soil has a neutral pH (6.0-7.0). In this soil, the color of the flowers will be purple or white, depending on the variety.

Suppose you planted a hydrangea, and it bloomed blue. This means that you have acidic soil, and the plant absorbs aluminum from the soil, and as a result, the flowers turn blue.

However, if the flowers are a different color and you want them to be blue, then you should add aluminum sulfate. This product is easy to find on sale. Just follow the instructions on the package, and everything will be ok. The soil will not immediately become acidic; it may take a year, so be patient.

If, after planting the hydrangea bloomed pink, it means that you have alkaline soil. Again, if the soil is neutral and you want to get pink flowers, you need to add garden lime to your soil to make it alkaline. This product is available in all garden centers. The process of changing the pH as in the first case may take some time, but the result will be worth it.

The best time to plant is Spring or Fall

Experienced gardeners plant hydrangeas at different times of the year and succeed in this. However, if you do not have much experience, I recommend planting in the spring or early fall.

Hardiness zone Month
3-4 May, the second half of August
5-6 April-May, end of August-September
7-9 April, September

For different climatic zones, the planting time will be slightly different.

If you live in the north, then plant a hydrangea no earlier than May, as there is a risk of late frosts. Also, the ground may still be too cold at this time.

However, if you plant a little earlier, nothing critical will happen, the plant will remain dormant until the right temperature.

In autumn (North USA), plant a hydrangea in the second half of August and until mid-September. This time should be enough for the plant to establish itself before the first frosts. The first frosts may occur in early October.

The best time for the south will be April-May. By this time, the earth has usually warmed up, and there is enough sunlight. In addition, soil moisture is quite high, which is an important factor when planting hydrangeas.

Spring is better for planting also because, at this time, the hydrangea usually does not bloom yet. Flowering takes a lot of energy from plants. Therefore, if the plant does not have flowers yet, it will be easier for it to establish itself in your garden.

The second best time to plant hydrangeas (southern United States) begins in September and lasts until the first half of October. I do not recommend planting earlier than this time, as August may be too hot.

Autumn is even a more favorable period because the weather is milder than in spring, and the land retains a lot of summer heat. Warm soil promotes better development of the root system. It is important that you plant a hydrangea 30-40 days before the first frosts. Otherwise, the plant will be harder to survive in the winter.

I do not recommend planting hydrangeas in the summer. Some gardeners are successful in this, but there are many subtleties. In colder climates and cloudy weather, you can plant a hydrangea, even in late June. However, in the middle of summer in the heat, do not do it in any case; otherwise, you are likely to lose the plant.

When planting, do not deepen the crown

It is best if it rained a few days before planting if there was no rain, water the plant several times to saturate it with moisture. Also, water the place where it will grow.

Choose a cloudy day; it will soften the plant rooting conditions. This is especially important in the first weeks.

Dig a hole twice as deep and three times as wide as the pot in which the plant has grown so far. This is needed to fill the pit with prepared soil. In such a soil, the roots will spread faster, and the plant will be easier to survive the transplanting shock.

Fill the pit halfway with the prepared soil mixture. Remove the hydrangea from the pot and place it so that the base of the crown is slightly above ground level. There should be only roots under the ground. The place where the roots turn into wood should be slightly higher (0.5-0.7 inches) above ground level.

If you cover the crown with earth, it can begin to rot, and as a result, you may lose the plant.

Next, add aluminum sulfate or garden lime depending on what color of flowers you want to get. I wrote about this above. Fill all the free space around the roots with the prepared substrate.

The next step is to water the hydrangea well. I always recommend watering the plants after planting in two stages. First, pour a little water. When the water rises and the soil settles a little, add more substrate that you have prepared. The second time, give more water to saturate the plant and soil.

The first year after planting the soil around should be constantly moist. Don’t let it dry out. If necessary (no rain and heat), water two or three times a week.

In case you planted a hydrangea in sunny weather, I recommend shading it for a few weeks. This can be done with a garden net. When the young shoots appear, the shade can be removed.

Immediately after planting, you can water the plant with liquid fertilizer. This is not a mandatory recommendation, but this type of fertilization will give impetus to the plant. In most cases, this is well reflected in further growth.

If the leaves begin to wither, you can cut a small part of the shoots (10-15%). This will reduce the amount of water that the plant evaporates, which should facilitate the rooting process. In addition, pruning stimulates the plant to form new growth.

Adequate Water

To care for your hydrangeas, you should ensure that they have adequate water. This means that the soil below the surface where roots remain moist. Moist meaning, you can feel the water in the ground with your hand. You will have to dig around the existing soil and touch it with your hands to see how moist it is. It should be damp but not soaking wet. You can also approximate how wet the soil is based on how the plant looks, and how much rain you have had, or watered it in the past.

When approximating it based on how the plant looks, it can be a bit deceptive because the plant will naturally wilt in the afternoon as it dries out a bit. It will also not respond immediately to the ideal amount of water because it takes time for water to be taken up by the plant. Use your best judgment and let yourself learn from experience.

You can make use of ground cover such as bark, wood chips, mulch, grass clippings, or similar. This sits on top of the soil and acts as a barrier between the sun and the surface of the ground. This stops the soil from drying out and keeps it moist. It will also slow seep down into the soil. It is providing a sustained water supply.

As the material on top breaks down, it will release micronutrients that the plant likes and will increase its health. After the plant has run its course for the season, many people mix natural ingredients into the soil, such as wood chips, bark, and soft green material trimmed from other plants. This combines with the existing ground and breaks down over time. It is providing a more nutritious and fertile soil, which causes the plants to grow more vigorously.

Use slow-release fertilizers

Most people grow hydrangeas for their lush inflorescences and beautiful colors. However, few people know that the plant is very difficult to form large inflorescences because it can be compared with the birth of a child. It takes a lot of energy.

In order for your hydrangeas to bloom with a large number of inflorescences, they need to be constantly fed. Otherwise, they will bloom poorly.

The first thing you need to feed the plants is organic fertilizer. I recommend using purchased quality compost. It should not contain pathogenic bacteria and pests.

Some people make their own compost, but I recommend doing so if you have experience. Otherwise, you can harm the plants with poor-quality compost.

The same applies to manure. Manure is a very aggressive product, and it can burn your hydrangeas. In addition, there are many diseases, so I do not recommend feeding any plants with manure. However, I must admit that many gardeners feed their plants with manure, and everything is ok. Therefore, use this fertilizer at your own risk.

The second type of fertilizer that I recommend using along with organic fertilizers is slow-release fertilizers. These fertilizers are made in the form of pellets. When you apply them under the plant, they slowly release fertilizer throughout the season in small portions.

Thus the same effect as at hydroponics is reached. The plant constantly receives the required amount of fertilizer. What matters here is not quantity but continuity.

There are a large number of such fertilizers on the market. They all have approximately the same NPK formula. However, in order for hydrangeas to have lush inflorescences, you need to use fertilizers with a high content of phosphorus. Phosphorus is responsible for the formation of large inflorescences.

Elements Ratio
N(nitrogen) 10
P(phosphorus) 30
K(potassium) 10

The table above shows the ideal NPK formula for hydrangeas. It is not necessary to look for fertilizer with such a proportion of elements. However, look for those where there is more phosphorus than other elements.

Also, avoid fertilizers that contain a lot of nitrogen, as this element stimulates the formation of large green leaves. As a result, you can get a large green bush with a small number of flowers.

Hydrangea easily multiplied by cuttings

Hydrangea reproduces well by cuttings. There are other ways, but this is the easiest and fastest.

The best time for reproduction is the beginning of summer. At this time, the plant grows rapidly, and the cuttings quickly form roots. The second advantage of this period is that the young plants have time to grow up and prepare for winter.

There are examples of successful rooting of cuttings in late summer. Yes, it is also possible, but there may be some problems. For example, new plants do not have time to form and may die during the winter, or you will have to keep them in a greenhouse all winter.

It is best to cut the cuttings in early June. This year’s young shoots are best suited for this. By early summer, they usually mature and become firm. Last year’s woody branches are not suitable for this.

Cut shoots 6-8 inches long with 3-4 leaf nodes. Do not cut cuttings that have the beginnings of inflorescences. Such cuttings will take root worse.

Remove all the leaves except the top node with the leaves. 2-3 leaves should remain on top. If on top, the leaves are not yet formed, then leave the leaves on one node, which is under the top. When removing the leaves, try not to damage the buds that are in the leaf nodes.

Trim the lower end of the cutting just below the leaf node. The leaf nodes have a lot of tissue from which the roots will be formed.

Next, you need to prepare the pots and soil. I recommend using quality soil for seedlings; it must be sterile and contain peat or moss. It will also be good if it contains perlite. Use soil only from well-known quality manufacturers.

Pots should be at least 6 inches deep. They should also be wide enough so that you do not have to transplant the plant in the first year. Fill the pots with soil almost to the top.

Dip the lower end of the cutting into the rooting hormone and insert it into the soil to a depth of 2-3 inches. You should deepen at least one leaf node, but it is better if it is two.

Water the cuttings well. The soil in the pots should be moist. Also, moisturize the leaves, it will improve rooting conditions.

Transfer the pots to the greenhouse. The greenhouse should be in full shade. If there is no shade, then you should shade the greenhouse to the maximum. Direct sunlight should not fall on the cuttings.

Humidity in the greenhouse should be at least 85-90%. You also need to spray the leaves of cuttings with water; in the heat, do it every day.

The air temperature should also not rise above + 86 ° F (+ 30 ° C). If the temperature rises higher, ventilate the greenhouse. Also, regardless of the temperature, ventilate the greenhouse every day.

In a few weeks (6-7), the roots will appear, and by the end of the year, you will get full-fledged plants. The following spring, they can be planted in the garden.

Hydrangeas can be affected by three types of diseases

The first type is a fungal disease. It occurs due to the ingress of fungal spores on or into the plant. The most common are Botrytis Blight, Cercospora, Anthracnose, and others.

All diseases are manifested in different ways, but their common feature is that their traces are visible on the leaves. Some appear as spots, others as dust, some affect the part of the leaf. I will not delve into these diseases in detail here, but will only give recommendations on how to avoid them.

  • Plant hydrangeas so that air circulates around them.
  • Make drainage if you have a high groundwater level.
  • Always disinfect the tool before trimming.
  • Do not leave plant remains under hydrangeas.
  • Use only quality organic fertilizers.
  • Several times a year, spray the plants with various fungicides for prevention.

The second is a bacterial disease. These include Bacterial Wilt and Bacterial Leaf Spot. They are manifested by spots on the leaves and root rot. These are very serious diseases. Unfortunately, there are no remedies against the first. Copper hydroxide can be used against the second.

How to fix yellowed hydrangea foliage?

The third type is a viral disease. These include the Mosaic virus, Ringspot virus, and more. Viruses are transmitted by non-sterile instruments, insects, nematodes. In most cases, these diseases are incurable, so here I can only give advice on how to act in case of infection.

  • Always work with sterile instruments.
  • Dig up the plant and throw it away from the yard, or burn it.
  • Clean the place where the hydrangea grew from the remains of plants and never plant other hydrangeas there again.

Several types of pests can damage hydrangeas

The most common pest of hydrangeas is aphids. These small insects accumulate on young leaves and begin to suck sap. As a result, the leaves wither and fall off. Aphids migrate to other leaves. Ants that feed on their sweet secretions make a great contribution to the spread of these insects.

The first thing you can do is wash off the pests with a stream of water, and it will solve the problem for a while. If there are too many of them, then you should use Neem Oil or insecticidal soap.

Larger insects pose a greater threat. These include Black vine weevil, Japanese beetles, and more. They can severely damage the leaves. As a result, the plant will survive but will look bad and will be weakened.

Large insects are harder to control because pesticides cannot be used during flowering so as not to harm the bees. Control methods include the use of Neem Oil, bactericidal remedies, and more.

The next type of pest is the spider mite. These are small insects that parasitize on hydrangeas. They are especially active in dry and warm weather. To get rid of them you should use special remedies called acaricides.

When should hydrangeas be pruned?

I have previously written a helpful article on this topic. Feel free to read that information on when and how to prune hydrangeas. But, briefly, you don’t necessarily have to prune your hydrangeas. It should be up to what you are comfortable with and your experience level. Pruning is a way of increasing the vigor and health of a plant. It does this by encouraging new growth as you remove the old and thick branches; the plant produces new growth, which reflects the nutrients in the soil.

Some people remove the current hydrangeas growth and grow a whole new bed. This is done to get better-producing flowers and take advantage of the properties of heirloom cuttings and seeds. When a plant has been in a specific climate and region, it adapts its genetic makeup to grow better for the conditions. Each subsequent cutting and seed production from successively grown hydrangeas increases their hardiness and health.

Therefore, some growers will take cuttings and seeds from the current year’s growth and then remove the hydrangeas to plant new ones. Over time they get a much healthier and better-producing plant with the same amount of nutrients. This is because its genetic makeup changes to reflect the conditions.

Conclusion

To maintain hydrangeas, you should make sure they get enough sunlight and water. Most varieties do best with the sun before midday, and shade after that. The soil that they are situated in should be moist to the touch. When the soil is dry, you should water them. This is sometimes hard to determine without digging into the surrounding soil. Some form of cover is good to stop the soil from drying out quickly and causes them to require less water to remain at optimum health.