Hydrangea envy is a reality, particularly when some people grow enormous, glorious plants with massive blooms, seemingly without effort. The good news is anyone can have them at their home, even if the only space you have is a corner on your patio. When you have the right variety and provide conditions they prefer, be ready to enjoy big blossoms outside your door. Amy Grisak is the PlantersPlace.com blogger who writes Pest Patrol. In this article, she explains how to grow hydrangeas in containers.

Choose the right variety

Many of the standard garden types of hydrangeas grow 5 – 8 ft. tall, but to find one that fits in a container look for cultivars of Hydrangea serrata or Hydrangea macrophylla such as ‘Bloomstruck’ by Endless Summer. One plant will easily fill a large container. For extra show, try tucking in a few annuals around the base of the plant for a pop of color.

Pick a pot

Hydrangeas require more water than many other container plants, so choose at least an 18 – 20 inch pot. It will keep the plant from wilting during even the hottest summer days. Hydrangeas are perennials, so by providing a larger container from the start, you won’t have to transplant it to larger one quite as often.

I do not recommend placing gravel or another substrate in the bottom of the pot. At one time, doing this was believed to allow proper drainage, but in reality, it tends to promote root rot. Make sure the container has adequate holes in the bottom for drainage. Fill the pot with soil and then give it a good soak. If the water runs out the bottom, the holes are adequate.

Use a high quality potting mix, and for gardeners in particularly arid climates, opt for the moisture-retaining types. Such soils help to hold onto water by not allowing it to evaporate quite as readily as a standard potting mix.

Plant and place your hydrangea

When planting your hydrangea in a container, simply tap the plant out of its existing pot and bury it so the top of the soil is at the level it was in the original container. Water it well. If you are not using a potting mix that already has fertilizer in it, give it a dose of fertilizer. You might want to try sprinkling a slow-release fertilizer like Osmocote® around it. Mix it into the first 1/2 inch of the soil. With Osmocote, you don’t have to think about it for the rest of the summer, which is always the easiest way to go.

Planting the hydrangea – photo by Amy Grisak

Unlike so many other brilliantly colored flowers, hydrangeas do not do well in full, blazing sun. Choose a location that receives morning sun with relief from the afternoon heat in dappled shade. If the plants are in the sun all day, they simply won’t bloom. This is particularly important in southern regions where the heat can quickly send the plants into dormancy.

For most of us, this means an eastern exposure is the best. Of course, that can change to some degree throughout the summer. But, that’s the beauty of growing them in a container. Simply move them to where they are the most happy. If a hot spot is your only option, one way to mitigate the situation is to place other tall plants in between the sun and your hydrangea. Or you can use a trellis of some type to create your own shade. The trellis can also serve as double duty to grow sweet peas, moon flowers, or any number or ornamental climbing plants.

Keeping your hydrangea producing throughout the season

To keep your hydrangea happy make sure it is well-watered. If it wilts on a regular basis, the stress will reduce the number of blooms. How much and how often mostly depends on your climate. To determine if water is needed, push your finger into the soil. If it feels dry a half inch below the surface, give the plant a good drink.

While hydrangeas bred specifically for containers typically grow extremely well in their given environment, if the summer is too hot and dry, it will practically shut them down until conditions change. That is major drawback of these particularly cultivars, although it’s still nice to have a hydrangea nearly anyone can grow. Stay ahead of the game by being vigilant on watering, and if it appears the sun is too much for them, move them or shade them as much as possible. If that doesn’t work, be patient. Sometimes, but not always, they’ll produce again when the conditions improve.

Pruning a hydrangea – photo by Amy Grisak

How to change the color of hydrangea blossoms

One of the amazing aspects of hydrangeas is how they can change the color of their blossoms depending on their soil acidity level. There are certain varieties of hydrangeas with pure white or lime green flowers, and those will not change in color. But for many other varieties, particularly the container cultivars, the blooms start out pink, but can turn different shades, including the true blue that is so difficult to find in the garden.

Developing the beautiful blue takes a bit of chemistry to accomplish. Pink flowers appear when the soil has a pH of 6.5 or higher. They’ll look more along a purplish hue when the level is between 5.5 – 6.5. For that gorgeous blue, aim for a pH of 5.5, or less.

To be truly scientific about it, take a pH measurement, which is easy enough to do using a simple kit from the local nursery, to see where your soil level looks on the scale. This will help you understand what and how much you need to add to achieve the desired effect.

For some gardeners, adding coffee grounds, peat moss, a sulfur amendment, and other organic materials to the soil is enough to give it a big enough acidic boost to develop the beautiful blues, but it often takes a much longer period of time since these materials do not assimilate rapidly.

A better method is to directly amend the acidity level by using a product containing aluminum sulfate, such as Garden Select™ from the makers of Osmocote. The beauty of Garden Select is it is as simple as the Osmocote fertilizer since you apply it and allow the soil chemistry to work its magic with the coated aluminum sulfate pellets that release the proper amount throughout the season. It is best applied before the plant sets buds, but you can start the process of changing the soil pH at any time of the season.

Another option for those who use a water soluble fertilizer is to use one specialized to boost the acidity level of the soil for plants such as hydrangea, azaleas, and some orchids. This needs to be applied during regular feedings every 7-10 days. The results are often good in many areas, although be aware that if you live in a region where the water is naturally alkaline, it might not drop the pH level as low as needed for the blue blooms. In this case, use a more neutral water source.

On the flip side, if you have naturally acidic soil and wish to have pink flowers, choose a soil amendment to increase the alkalinity. There are a number of possibilities, including basic lime, that will do the trick.

Keep in mind that while it seems like magic to be able to turn a flower a different color, it doesn’t happen overnight. It can take weeks, and in some cases, an entire season to be able to tweak the soil to achieve the color you want. Fortunately, hydrangeas are perennials so you have the time to create the color you love.

Enjoying the blooms

Hydrangea blossoms are stunning in a container on the porch or patio. Sometimes they are simply irresistible. There’s nothing more classic than an opulent bouquet of hydrangea blossoms. When you cut the flowers, give them enough stem to fit in a vase. Just don’t trim them too severely.

This holds true even if you wish to hang them upside down to dry. Hydrangea blossoms are known to dry beautifully. In this case, snip them, fashion a paper clip into a hook and such it through the end. Then, hang them in an area out of the sun. Within a couple of weeks, you’ll have a dried flower that will be beautiful for years.

Pruning at the end of the season

Deadhead blossoms as they are spent throughout the summer. For most hydrangeas try not to prune them much beyond the first part of August. Hydrangeas, including the container varieties, bloom on old and new wood. If the pruning is too heavy, you may be eliminating potential flowers for next year.

The best plan for pruning is to shape your hydrangea the way you like the best. If there are particularly long stems, trim them back to fit into the style with the others. But, be cautious. This means you will probably have spent blooms on your plant through the winter. It won’t hurt anything. It might even add a little winter interest and a bit of protection going into the cold months.

Overwintering your container hydrangea

To keep your container hydrangeas alive during the winter, bring them into a basement or garage before there is a hard freeze (in the 20s). Protect the base of the plant from drying out or excessive freezing and thawing cycles by placing some sort of mulch, such as shredded bark or straw, inside of the container because additional flower buds will grow at this level next year. Keep them moderately moist, but not over saturated.

Another option, depending on your location and the type of container you use, is to bury the entire pot and plant. Dig a hole deep enough to have the top of the container level with the soil level and set the pot inside. Mulch at least a foot thick with straw or shredded bark. The ground is an exceptional insulator. With enough mulch on top, the hydrangea should pull through beautifully, particularly if you live in an area with heavy snow cover.

In the spring, don’t place them outside until the danger of frost is passed. If you just can’t wait, at least be ready to bring them inside when there is a threat of cold. This is the same for the containers you place in the ground. Don’t be too quick to expose them to the erratic spring conditions unless you are ready to save them during a cold night.

So worth the effort

Growing hydrangeas in containers brings a bit of an old fashioned garden directly to the porch or patio. They do, however, require consistency in watering. If so inclined, tweak the soil conditions to obtain different colored flowers. Whatever you decide on color, hydrangeas in containers will provide a consistent source of beautiful blooms throughout the season.

Hydrangea lover – photo by Amy Grisak