With generous blooms of ever-changing intense colors, hydrangeas have always had a unique place in the hearts and landscapes of garden lovers.
If you know when to plant hydrangeas, you’ll enjoy their famously colorful blooms for years to come with very little maintenance. Here’s a quick look at the best planting times for each type.
When to Plant Hydrangeas: Ideal Planting Times
Picking the right time of day and the right season to plant your hydrangeas will give them the best possible odds. Take a look at this breakdown of the ideal planting times.
Time of Day: Early Morning or Around Dusk
Early morning or around dusk is when you should start soaking your hydrangea before removing it from the pot.
Hydrangeas thrive in cooler temperatures and don’t do well in the heat, so avoid planting your beautiful specimen at any other time of day.
Time of Year: Fall or Spring
Fall is the best time of year to plant hydrangeas. If you miss the fall window, wait until it’s early to mid-spring to plant them.
Planting in the fall gives your plant about six weeks before the first frost. You want your plant to get accustomed to its new surroundings and form a healthy root system before it’s time for it to bloom.
The more tender cultivars of hydrangea, like mophead hydrangea, are best planted in spring or by early fall at the very latest. You need to give your hydrangea time to establish its roots before the cold weather starts.
Less-Than-Ideal Planting Times
Time of Day
Avoid planting hydrangeas in the hot midday or afternoon sun. You don’t want the leaves to blister or the blooms to wilt.
Time of Year
Hydrangeas aren’t finicky plants, but planting them in the summer should be avoided. They can’t handle a lot of heat and will even wilt if they remain in the sun for over three to four hours.
Some people will plant most hardy hydrangeas all over the year as long as the ground’s not frozen, but it’s not the norm and is quite harsh on the plant.
Even cold-hardy cultivars like Ice Crystal Oakleaf won’t thrive if planted in winter.
Hydrangeas by Hardiness Zones
When it comes to the climate a particular cultivar of hydrangea can handle, the USA is divided into zones. Each zone is determined by the lowest average winter temperature.
You’ll notice the same variety of hydrangeas in several zones. That means it’s safe to plant it in these various temperatures. Here’s a quick look.
Zone 3
Panicle or PeeGee hydrangeas
This type offers the highest variety of cultivars for zone 3. These include:
- Bobo
- Firelight
- Little Lime
- Little Lamb
- Pinky Winky
- Quick Fire
- Ziinfin Doll
- Tardiva
- Unique
- Water Moth
Annabelle Hydrangeas
Blooming from June through September, this type includes:
- The Invincibelle series
- The Incrediball series
Zone 4
Panicle Hydrangeas
Some Panicle hydrangeas are zone-4 hardy. These include:
- Grandiflora
- Limelight
- Compacta
- Pink Diamond
- White Moth
Hydrangea Arborescens
This type is also zone-4 hardy and includes the following varieties:
- White Dome
- Haas’ Halo
- Incrediball Blush
- Grandiflora
Zone 5
Panicle Hydrangeas
These include the following varieties:
- Bobo
- Firelight
- Quickfire
- Little Quickfire
- Limelight
- Little Lime
- Little Lamb
Bigleaf Hydrangeas
These are famous for their vividly blue blooms.
- Cityline series
- Edgy Series
- Let’s Dance series
- Endless Summer series
Zone 6
Oakleaf Hydrangeas
These are ideal for zone 6. They go from soft green to ivory and finally, turn to rose-purple in July.
- Snowflake
- Harmony
Panicle Hydrangeas
Again, these do well in zone 6.
Zone 7
These include a number of interesting varieties:
- PeeWee dwarf variety
- Snow Queen
- Harmony
- Alice
Zone 8
Bigleaf Hydrangeas
- Mopheads
- Lacecap
Oakleaf Hydrangeas
Zone 9
Many popular hydrangea varieties can be grown in zone 9, but it’s ideal to start with a variety that can handle the heat.
Oakleaf Hydrangeas
These are ideal because they retain water and don’t need to be watered as often as other types.
Climbing Hydrangeas
These can handle hot, dry locations well.
Bigleaf Hydrangeas
Another type well-suited to arid environments.
The Planting Process
Regardless of type, planting hydrangeas is a pretty straightforward process. There are, however, a few important considerations to keep in mind before you decide on a cultivar.
Check Your Soil Acidity
Unless you go for something that will stay white like the Hydrangea Arborescens Annabelle cultivar, you’ll probably pick a type of hydrangea that will change color over the years.
If you want your blooms to be blue, you’ll need acidic soil or a pH of 5.5 or lower. Pink flowers require alkaline soil or a pH of 6.5 or higher.
Checking the acidity levels of your soil enables you to know the necessary additions to your soil for the color that you’d like to see.
Know Your Zone
If you’re in a colder zone and you plant a hydrangea that belongs to a warmer zone, your plant may grow but it will probably yield only leaves without ever flowering.
Choose the Right Spot
The first thing you should do is to survey your garden carefully. Hydrangeas cannot handle full sunlight or high temperatures in the mid-90s, so you need partial shade. There are two ways to do that.
First, you can emulate Mother Nature and plant your hydrangea under the deep shade of tall trees.
In forests, hydrangeas grow underneath trees. A spot like that gives your hydrangea its ideal gentle, filtered sunlight. In addition, tree leaves that fall and rot provide your plant with nutrient-rich soil, another Mother Nature emulation.
Alternatively, you can pick that part of your garden that only gets the early morning sun and is afterward in the shade. This ensures your hydrangea won’t be exposed to the rest of the day’s harsher light and heat.
Planting several hydrangea plants provides a delightful swathe of color. If you’ve decided on planting lots of hydrangeas, make sure you space them in a way that leaves ample room for the roots of each plant to grow.
Digging
The hole you dig to plant your hydrangea should be double the depth and the width of the pot. Avoid digging a hole deeper than that. Get rid of the subsoil.
What to Add to the Soil
There are a few staples you generally add to the soil when you plant hydrangeas.
- Fertilizer or bone meal
- Acid compost, which doubles as mulch
- Aluminum sulfate for blue blooms
- High-phosphorus fertilizer for pink blooms
- The top layer of soil that you dug up
- Organic pellets
Keep in mind that the amount of fertilizer depends on the season you’re planting.
When Planting in the Fall
Use less fertilizer if you’re planting in the fall.
Fertilizer helps shoots grow faster, which is not the goal here. You want to help the roots, not the shoots, grow faster. When the cold starts, your plant will have a good root system ready to face the winter.
When Planting in the Spring
Be generous with the fertilizer if you’re planting in the spring.
Now that you’ve left the cold weather behind, your hydrangea has enough time to create a good root system without sacrificing shoot growth.
Choose Your Plant’s Good Side
Before you start backfilling, remember to turn the pot so that the prettier side of the plant is visible.
The First Backfilling
Mix all your ingredients together and add shovelfuls until you’ve filled half the hole.
The First Watering
Soak your hydrangea thoroughly. Leave it alone for about an hour until the water has drained completely.
The Final Backfilling
Add more shovelfuls of your soil mix until you’ve covered the roots.
After you’ve completely backfilled the hole, lightly tamp the soil without making it too compact. You need to leave room for your plant to grow roots.
The Second Watering
Water your plant thoroughly.
Pruning
Like all flowering perennials, hydrangeas need to be pruned once they’ve finished flowering. If you prune them correctly, they’ll grow to more than double their post-pruning height in a year.
Feeding
To ensure your hydrangea gives you those rich hues, make sure you feed it every two weeks throughout the summer.
Unique Hydrangea Types
There’s a hydrangea for everyone. If you’re unsure which type to pick, take a look at these special cultivars. Each type is hardy all the way down to zone 3, so they can withstand substantially cold temperatures.
Lime Rickey
An exceptionally sturdy type, the Lime Rickey can withstand rain for hours without snapping.
Invincibelle Wee White
This dwarf plant is ideal if you’d love to plant hydrangeas but don’t have room for a cultivar that will keep growing.
Invincibelle Spirit II
This pretty deep-pink hydrangea is an excellent standalone in your garden. It also keeps on blooming through fall. Even better, for every plant sold a dollar is donated to the Breast Cancer Research Foundation.
Limelight
This type is so easy to grow even a black thumb couldn’t kill it. It’s also remarkably heat-tolerant and can thrive all the way up to zone 9.
Final Thoughts
Changing from pink to blue or the other way around, with some blooms even reaching the size of a human head, hydrangeas come in enough shapes, sizes, and colors to make the possibilities seem endless.
Hydrangeas not only provide intense splashes of color in your garden; they also make excellent container plants and centerpiece arrangements whether fresh or dried.
As long as you know your zone and soil and pick the suitable cultivar and the right time to plant it, you’ll have a beautiful, delightfully low-maintenance garden plant to enjoy for years to come.