Hydrangea Plant: Growing, Pruning, Diseases, Changing Colour, Containers Growing...

The Hydrangea plant.

One of the most sought after plants for a garden.

The large flower clusters in shades of whites, pinks and blues catch the eyes of anyone walking by.

They are easy to grow, low maintenance and like to have some shade in the middle of the day when the sun is at it's peak.

Panicle hydrangeas can handle full sun but they need to stay moist during the hot summer days.

How to Grow Hydrangeas in Containers

Hydrangea in containers make nice focal points on decks, patios or on a stand in your yard. Growing Hydrangeas in containers is easy but the soil needs to stay moist. 

It's also easier to change the PH level to make blue or pink flower colours.

Some containers can get heavy so it might be best to put the pot on a stand with wheels so you can slide it around. 

You will also want to protect your Hydrangea plant during winter from the cold harsh winds.

• You can wrap the pot with burlap
• store them in a corner of your yard that is less windy
• or set them in your garden surrounded by other plants

Wherever you put them keep them uncovered over the winter so that the snow will help keep them moist.

You can also heel your Hydrangea plant in the ground over winter. What does "heeling them in" mean? Dig a hole in your garden where you have room and plant them. Come spring before the new growth starts, you can dig them up and put them back in the pot. That way the wind won't dry out the roots and the plant will be very happy.

How to Prune Hydrangea Plants

Pruning Hydrangea plants can get very complicated if you want to get into a lot of details, but it doesn't have to be.

If you don't know the variety of Hydrangea you have I would prune it right after it's done blooming.

If you do that you will not cut off any flower buds for next year.

I have at least a dozen different varieties of Hydrangeas growing in my gardens. To be honest, unless I look it up, I'm not sure when to prune most of them. Other then Annabelle and PG, which I know you can prune in early spring. The rest get pruned as soon as they stop flowering.

If you know the variety and want to prune it at the right time, here is a list of when to prune.

• Panicle and smooth Hydrangeas, you can prune in late winter to early spring, before new growth starts to show.

• All other Hydrangeas you can prune as soon as their flowers fade in late summer to early fall.

Here are 2 points to think about when trying to ID your Hydrangea:

• If the flowers are blue or pink and are blooming during summer and you can prune them right after flowering.

• If it's not blue or pink and it blooms spring to early summer then you can prune it in later winter to early spring.

Want to figure out what Hydrangea types you have? Here is an awesome video from Laura from Garden Answers that should help.

Varieties

There are about 70 – 75 different varieties of Hydrangeas to choose from and the varieties keep climbing as there are new varieties every year. Below I have a few varieties that I offer in my nursery. They are spectacular when they are in bloom.

Hydrangea Plant Pest and Disease Control

Hydrangea Plant Diseases

Botrytis Blight – This is the main disease that will affect your Hydrangea. It’s a fungal disease that will kill flower buds sometimes before they open. The leaves will become infected when the petals land on them. To prevent this disease try watering in the morning or early afternoon at the soil level. Good air flow around the plant will also help. You may need to use a fungicide to clear up the problem.

Leaf Spots – also called Cercospora, is a fungus that happens when the water stays on the leaves. To get rid of this disease try using liquid kelp, compost tea or garlic oil. If these methods fail you can use fungicides called thiophanate-methyl or chlorothalonil. They will clear it up but you might want to try the organic ways first.

Powdery Mildew on plants – looks like fuzzy white cotton on the leaves of your plant. You can prevent it by making sure there is good air circulation around the plant. You can use neem oil to help clear it up but if need be a fungicide for powdery mildew will work.

Hydrangea Rust – only infect smooth Hydrangeas. It won’t kill the plant but it’s not pretty to look at. Control it by cleaning up any debris around the plant and make sure there is good air circulation.

Viruses – There are several viruses that can affect Hydrangeas. The most common are ringspot virus, mosaic virus, tomato ringspot virus. If your plant becomes infected there are no cures, you will need to dispose of it. You can prevent viruses by:

• Disinfecting your cutting tools before using them
• Watch for and destroy bad insects, like aphids or nematodes that come in contact with your plants
• Also keep the area clean of debris like fallen leaves and dead flowers.

Anthracnose – heavy fertilizing will cause anthracnose along with long rainy seasons. Using liquid kelp, compost tea or garlic oil will also help clear up this infection.

To help prevent diseases on your plants try these methods.

Good air circulation will prevent most of these diseases. To achieve this, try thinning the inside of the plant. Taking a few branches out from the middle will open up the plant and let air flow around it.

Watering your plants early in the day will also help prevent these diseases. Also watering at the soil level will prevent water from sitting on the leaves.

Hydrangea Plant Pests

There are a few garden pests that will attack your Hydrangea but they are easy to control.

Spider Mites – Very tiny spiders that are better to see with a magnifying glass. Learn more about spider mites and how to get rid of them here.

Aphids – they suck the sap out of your plants leaves and are different colour. Read more about Aphids and how to control them here.

Japanese Beetles – These coppery green bugs are a gardener’s worst nightmare. They can take over a plant in one day and pretty much destroy the plant. Read more about Japanese beetles here.

Slugs and snails – There are many easy to control slugs and snails. Read more here.

Other Pests

A few other pests that might visit your Hydrangeas are

• scale insects
• Whiteflies
• Caterpillars
• Lygus Bugs
• Rose Chafer

They don’t cause much damage to your Hydrangea plants and I wouldn't worry about them unless there are a huge number of them.

How To Make Pink or Blue Hydrangea Flowers

Here is what you need to know to make your Hydrangeas blue or pink.

BLUE Hydrangea Flowers

Some varieties of Hydrangeas are suppose to be blue but sometimes they end up more pink or purple. If that happens, you will need to increase the acidic level in the soil. The soil PH should be around 5.2 - 5.5.

If you need to decrease the soil PH you can add coffee grinds, citrus peelings or grass clippings. You can also increase the PH by adding aluminum sulfate. 

Adding a fertilizer with low phosphorus and high potassium will also help. The numbers should be around 25/5/30 with the 5 being the phosphorus and 30 being the potassium.

Changing the colour will take time and won't happen over night. It could take up to a year for you see the new colour emerge.

PINK Hydrangea Flowers

Getting blue Hydrangeas to turn pink is a little harder to do but with a little patients it can happen.

You need to add a gardening lime to the soil several times a year. The PH for pink Hydrangeas should be around 6.0 - 6.2. 

Fertilizer with higher phosphorus will help keep the aluminum out of the soil. The numbers should be around 25/10/10.

If your having problems changing the colour of your flowers, you might want to consider this:

• Concrete foundations and/or sidewalks will have an effect on the flower colour. The lime from the concrete will seep into the soil and make pink flowers instead of blue.

• Another thing that might affect the flower colour is the water you use to water your plants. You should have it tested to see what the PH might be as it will effect the blue or pink colour.

BTW if you get purple flowers, know that it means your PH level is exactly between blue and pink. 

How To Dry Hydrangeas

If you want to dry your Hydrangea blooms, here is a great video from Patti Elhoff the author of Upcycle with Decoupage.

She shows you how to dry and dye the flower blooms and I think you will enjoy it.

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