Bringing the gorgeously large blooms of a hydrangea inside might seem like a fool’s errand.
Can you grow hydrangeas indoors, I hear you ask?
Yes! It is entirely possible to grow hydrangeas indoors, if they are given the correct care.
Enjoying a hydrangea bloom (also known as Hortensia) year after year makes the minimal effort required to care for one well worth it. With the right tools and know-how, it is possible to keep potted hydrangeas indoors alive – and even see them thrive – in your home.
Pulling together extensive research, this article will answer all your questions about hydrangea care indoors.
Table of Contents
- Which Variety of Hydrangea Grows Best Indoors?
- Where Should I Put It?
- Why Does It Need Different Conditions in Different Seasons?
- How Often Should I Water?
- How Will I Know If I Am Overwatering or Under Watering My Hydrangea?
- How Much Humidity Do They Need?
- Should I Be Fertilizing?
- What Soil Is Best?
- How Do I Help My Plant Re-Bloom Next Year?
- How Do I Maintain or Change the Color of My Hydrangea?
- How Do I Keep It Looking Bushy and Healthy?
- How Large Can a Hydrangea Grow Indoors?
- How to Prevent Dry Soil?
- How to Avoid Scorching and Burning?
- Why Aren’t My Hydrangeas Flowering?
- Dealing With Pest Infestations
Which Variety of Hydrangea Grows Best Indoors?
Not all hydrangeas can flourish indoors.
The Hydrangea macrophylla is one of the best varieties for indoors and also for novice owners.
The hydrangea macrophylla (aka the Mophead hydrangea) is very hardy and is easy to grow. The mophead is especially suited to indoor life because it can thrive in a container or pot.
A Hydrangea macrophylla would make a lovely contribution to any houseplant collection as they come in lots of beautiful colors and their blooms can last for months. The combination of their huge blooms and lush green leaves make them a great addition to any interior space.
Where Should I Put It?
Finding the perfect location can make the difference for your plant’s health and beauty.
These plants like sunny spots with lots of bright, indirect light (at least 4 hours per day). They also love being taken outdoors to enjoy the morning sun in the summer.
The vast majority of hydrangeas like moderate to cool rooms (around 16°C or 60°F will be fine). If the leaves begin turning brown or start to look crispy, the room might be too warm for your hydrangea.
During hibernation, they prefer cooler, darker spots.
In the winter move your hydrangea to an unheated room (around 7°C or 45°F), like a porch, garage or north-facing room away from the window. Though be careful to keep your hydrangea away from frost.
Make sure your hydrangea is away from heat sources and drafts at all times. Hydrangea can be very susceptible to shock from abrupt changes in temperature and humidity.
Why Does It Need Different Conditions in Different Seasons?
In order to bloom, hydrangeas need to go through a dormant period (or hibernation).
Reducing the temperature, light conditions, watering and fertilizing ensures that the plant goes dormant and can then prepare itself for a beautiful bloom in the spring.
If you keep it in the same temperature and light conditions all year, it is unlikely to rebloom.
Avoid changing the temperature and light conditions abruptly as hydrangea can respond negatively to sharp shocks. Instead, gradually increase (or decrease depending on the time of year) the temperature and light.
You could try placing your hydrangea in an in-between room for a few weeks to give it time to adjust.
Remember to reduce watering and fertilizing when your plant is dormant and enjoying cooler temperatures and to increase them in the bloom seasons.
How Often Should I Water?
They like moist but not waterlogged soil. Finger test the top 2-3 cm of soil every day and water before that top soil dries out.
Avoid using cold water as this can shock the roots and hinder your plant’s health, especially when it is in bloom.
Semi-regular plant baths will keep your hydrangea especially happy.
Submerge the bottom fifth of the pot in a water tub. Try to bathe your plant weekly if you are keeping it in a particularly bright and warm location.
Your hydrangea will need more frequent watering when it is in bloom and much less water when it is not. Using the finger test, rather than a constant watering schedule, will help you to adapt your watering frequency to the particular needs of your plant throughout the year.
Ensuring your pot has drainage holes will help to prevent waterlogged soil and root rot, which can be detrimental for your plant baby.
Watering your hydrangea with distilled water or rainwater will help avoid some of the problems of tap water – especially the slight pH level variations and presence of chemicals like chlorine.
How Will I Know If I Am Overwatering or Under Watering My Hydrangea?
Finding the balance between overwatering and underwatering can be tricky.
Especially as hydrangeas are moisture-loving plants (hence the prefix hydro-, meaning water). But watching out for these signs will help you to avoid overwatering your hydrangea:
- Yellowing leaves
- Rotting lower leaves
- Premature leaf drop
- Loss of flowers or buds
- Root rot
Underwatered hydrangeas tend to show at least some of the following signs:
- Premature flower loss
- Dry leaves
- Stunted growth
- Severe wilting
As with many moisture-loving houseplants, it is wise to experiment with water levels and watch carefully for the warning signs listed above.
There are many factors which determine how much water your plant will need, from the room temperature and humidity to the size of the pot.
How Much Humidity Do They Need?
High humidity is preferable, ideally between 40-45% relative humidity, especially during the bloom season and for bud growth.
If the humidity is too low (or the temperature too high), your hydrangea’s leaves may start to turn brown or curl over.
Regularly dusting your hydrangea’s leaves and misting its foliage will help to keep it happy. Using a humidifier or a pebble tray will help your hydrangea thrive in a dry room.
Want to learn more about caring for humidity-loving houseplants? Read our article on the Best Humidifiers for Plants.
Should I Be Fertilizing?
The simple answer is that these house plants require more fertilizer than outdoor ones. Using a half strength fertilizer solution once per week while the plant is blooming should satisfy your hydrangea.
Use a generic houseplant or potassium-based fertilizer during its bloom. Tomato fertilizer also works very well.
Remember to dilute your chosen solution to avoid root burn.
By the end of August you can reduce your fertilizing regime to once a month (and with a much weaker solution) to allow your plant to hibernate. At this time stick to a generic houseplant fertilizer, rather than a potassium-heavy solution.
The more complex answer is that how much you should fertilize depends on the type of hydrangea. See our fertilisation schedule to help meet your plant’s needs:
- Big leaf varieties (the most common): fertilize every 10 days between March and June
- Smooth hydrangeas: fertilize once in late autumn
- Oakleaf hydrangeas: fertilize once in April to encourage a lovely bloom and once in June
- Panicle hydrangeas: fertilize once in April to encourage a lovely bloom and once in June
What Soil Is Best?
Most varieties of indoor plant soil will be satisfactory. For the best outcomes add a thin layer of shredded bark across the top to aid water retention.
Acidic lime-free soil is best for blue hydrangeas. Use alkaline soil for pink ones.
See our section on how to maintain or change the color of your hydrangea’s bloom.
How Do I Help My Plant Re-Bloom Next Year?
When you ask hydrangea owners what their favorite thing about hydrangeas are, they will most likely say their beautiful blooms. So let’s look at how you can help keep your hydrangea at its most beautiful, year after year.
As hydrangeas are perennials, it is possible to get a vibrant bloom each year.
But matching that stunning first-year bloom can seem tricky at first. This is especially true if your potted hydrangea was kept in a greenhouse at the start of its life to speed up the growing process.
But it is perfectly possible to enjoy beautiful reblooms in the following years.
Take action during your plant’s dormant period, which begins around early autumn. Following these simple steps can help you enjoy a wonderful hydrangea bloom every year:
- Trim back your hydrangea after the bloom. Don’t worry about giving it a brutal trim – cutting it back by half will help you get a lovely bloom the next year. Remember to cut the stems at a 45° angle to improve water absorption.
- Repot your hydrangea in a pot that is 5-10 cm deeper than the old pot.
- Use a high quality potting soil for best results. Add perlite if the mix feels too thick and heavy.
- Separate out the roots and press the soil firmly around the roots to limit air pockets and promote even growth.
- Add a thin layer of shredded bark over the top of the soil to boost water retention.
- Keep your hydrangea in a brightly-lit room, but away from direct sunlight. If this is not possible, use an artificial growth light (but watch out for any artificial heat!)
- Put your hydrangea out in the sunshine during the spring and summer months. Hydrangeas especially love morning sunlight, which isn’t as hot as in the afternoon.
- Remember to water and fertilize regularly. (See our sections on ideal watering schedules and fertilization for tips.)
- Help your plant’s hibernation by moving them to a cooler, darker spot in the winter months. Gradually increase the light and heat six weeks before you want your hydrangea to rebloom.
How Do I Maintain or Change the Color of My Hydrangea?
Once you have selected a beautiful hydrangea after admiring its vivid color, the fact that soil acidity levels can change its color can be quite irritating.
Luckily, there is a solution for maintaining your hydrangea’s color.
Changing the soil pH level can transform your hydrangea’s flowers from blue to pink and maintaining the level will keep them the same. Also, they have an advantage over outdoor ones because it is easier to maintain the acidity in potted soil.
Blue hydrangeas (whether inside or outside) need acidic soil to remain blue. Adding sulphur to your plant’s soil while it is blooming will help (you are aiming for pH 5.5 or lower).
Or perhaps you would like to transform the color of your plant? Increasing the alkaline content of your soil to above pH 7 will turn the flowers pink. Use lime-water to make the soil more alkaline. And a neutral pH level (somewhere between pH 5.5 and pH 7) can result in a unique mix of pink and blue, or even a pretty shade of purple.
However it is important to note that not all varieties can change color. It is often easier to buy the color you want and maintain it, rather than changing the color.
How Do I Keep It Looking Bushy and Healthy?
Regularly removing dying leaves, as well as any dropped leaves or petals, will improve the growing conditions. Also pluck any flowers past their bloom.
Prune your hydrangea (with sharp tools) to help it grow more bushy. Between late winter and early spring trim spindly off-shoots to promote thicker growth.
Avoid cutting through yellowing tissue or using unclean pruning tools as this can increase the risk of infections.
How Large Can a Hydrangea Grow Indoors?
A well looked after hydrangea can grow up to 3 feet in height and 2.5 feet in width.
Hydrangeas are moderate-speed growers and can reach their full growth height in 4-6 years, if their basic needs are met.
Common Issues and How to Avoid Them
Here is a short and sweet summary of the most common problems and some simple tips for avoiding these issues.
How to Prevent Dry Soil?
Although hydrangeas can withstand mild droughts, a persistent lack of moisture will endanger the plant.
The plant will begin to wilt and flowers may be lost. It will stop growing and, if the wilting becomes severe, may not recover.
How to Avoid:
- Keep your plant away from direct sunlight.
- Water whenever the top 2-3 cm of soil are dry.
- Keep the soil constantly moist during the growing period.
How to Avoid Scorching and Burning?
Too much direct sunlight can scorch and burn your entire plant.
The signs to look out for include brown or crispy leaves, dry leaf-edges and stunted growth.
How to Avoid:
- Select a location which will give your plant at least 4 hours of indirect sunlight each day.
- Remove sun-damaged leaves.
- Increase watering.
Why Aren’t My Hydrangeas Flowering?
If your beautiful houseplant is failing to flower, or not producing many flowers, it may be because the dormancy or hibernation period was insufficient.
How to Avoid:
- Reduce the temperature your plant experiences during autumn and winter.
- Water and fertilize your plant less often during this dormant period.
- Increase the temperature and access to indirect light during spring and summer.
- Regularly water and fertilize your plant during the bloom season.
Dealing With Pest Infestations
Hydrangeas are quite susceptible to insect infestations because their large beautiful foliage hides infestations until it is too late.
Mealybugs (small, white critters) burrow into the hidden nooks of hydrangeas and quickly infect the entire plant.
Spider mites are also common and are hard to locate due to their semi-transparent color. If left, they will slowly extract the chlorophyll from a hydrangea’s leaves.
How to Avoid:
- Regularly check under your hydrangea’s leaves and along the stems to locate any infestations early on.
- Look out for small webs and yellow bumps which may indicate a spider mite infestation.
- Take preventative action by keeping your hydrangea away from doors and windows. Maintain air circulation in the room to reduce pest outbreaks and diseases.
- Thoroughly inspect your hydrangea before bringing it back indoors after it has enjoyed some summer morning sun.
- Also watch out for the development of root rot and powdery mildew.
FAQ About Hydrangea Care
How long can an indoor hydrangea last?
The answer to this question is solely dependent on how you take care of them. If their living conditions are perfect and their care routine is immaculate, then they have a great chance of lasting for 50 years!
Will an indoor hydrangea bloom again?
Most people buy these plants at their local garden center or even perhaps at some grocery stores and shopping centers. Unfortunately, after the first bloom most people end up throwing away these beauties. If you follow our care tips here, you won’t end up having this problem and can count on blooming hydrangeas every year.
How big will it get?
A fully mature potted hydrangea will do well in a 16”-24” pot and can reach above three feet tall if no pruning takes place. It will take roughly four to six seasons for it to reach its full size in a pot. So when you receive your first foil wrapped hydrangea and plan to keep it for many years, make sure you plan a good spot for it in your home.
Hydrangea Care is Both Easy and Rewarding
Caring for this particular type of houseplant can be very rewarding. They are not too demanding and produce a truly beautiful bloom which lasts for much of the spring and summer season.
Key Tips to Remember
- Avoid overwatering or underwatering – hydrangeas love moisture but are susceptible to root rot if over watered.
- Reduce temperature, light exposure, watering and fertilization during the dormant months of autumn and winter.
- Increase watering (using the finger test to identify when your plant needs more water) and fertilize every 10 days or so during spring and summer. Keep your hydrangea in a light spot, but avoid direct sunlight which can scorch your plant.
Watch out for what they hate most: dry soil, too much direct sunlight, infestations and the belief that hydrangeas can only survive outside.
Liked What You Read?
Who knew hydrangeas came in so many different colors? Needless to say, they’re awesome! Want to discover more surprises about houseplants that could be yours one day? Check out one of the articles below or be blown away with our growing collection of houseplant care tips. Don’t forget to pickup the best houseplant care gear to ensure that your green babies stay happy, healthy and fabulous!
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