Whether you are creating a dreamy English cottage garden or searching for the perfect potted plant for your porch, hydrangeas add a whimsical feel wherever you plant them. These beauties burst with clusters of blooms in various colors, such as pink, white, blue, purple, and green.
Plus, most hydrangeas are perennials, which means you will have gorgeous blooming bushes year after year. Although they are relatively low-maintenance, you need to know when to plant hydrangeas so they can establish strong roots and thrive.
We spoke with gardening experts to get the scoop on when to plant hydrangeas by zone and type so you can keep them healthy and enjoy their dazzling blossoms every year.
12 Stunning Hydrangea Varieties You Need to Know About
When to Plant Hydrangeas by Type
"When planting hydrangeas, time is of the essence, like with most plants. But you do have a pretty large window to play with. The key is to find a period when you don't risk frost and to avoid drought at the same time," says Amber Noyes, horticulture and gardening expert and executive editor of Gardening Chores.
Here are the common types of hydrangeas and when to plant them according to the experts.
Hydrangea Shrubs
Noyes says fall and spring are the best times to plant hydrangeas shrubs. You can technically also plant them in the summer, but it is not recommended. She says if you do, you must ensure that you keep watering the shrubs and avoid full sun because heat can stunt their efforts to set roots in the new soil.
"Transplant your hydrangea when it is dormant, and absolutely avoid it when the plant is in bloom. At this stage, it is at its weakest, and the least you can expect is that all the large blossoms wilt away, but foliage and growth will suffer as well," she explains.
Jen McDonald, certified organic gardener and co-founder of Garden Girls, says where you plant is also vital. "Because there are so many different varieties of hydrangeas, it's important to select the variety based on where you'd like to plant it," she advises. "Choose a location that favors the hydrangea you select."
Climbing Hydrangea
Should you plant climbing and shrub hydrangeas at different times? Noyes says the answer is no; the same timing applies to both types. Fall is typically the best time to plant, with spring being a close second.
"Planting in fall is often preferred because the hydrangea is approaching or already in its dormant phase and is therefore not using much energy. It is in the process of transitioning energy from the foliage back into its roots, minimizing the potential for damage," she explains.
There is a narrower window with spring planting, and it does come with potential risks. "At this time, the hydrangea is initiating new buds and shoots growth, transferring energy from the roots to the leaves. If the leaves have already started to open, the plant may suffer from transplant shock, potentially preventing flowering for that year or resulting in a weak bloom," she warns.
She also says that if you opt for spring planting, make sure that it is at the latest when you see tiny new buds growing on the branches and never past the first few leaves that have fully opened.
Potted Hydrangea
"When it comes to planting hydrangeas in pots, however, the opposite is true. It is better to do it in spring, and fall comes as a second choice, but not as close. The point is that plants in pots are not as sheltered from frost as they are in the ground, and you don't want to take a risk," Noyes says.
She advises taking some precautions if there is a chance of frost, such as wrapping up your container with something warm, like straw, for example. "However, in warmer climates, transplanting them in fall is quite feasible and usually successful."
Potted Hydrangea to In-Ground
If you are wondering when to plant hydrangeas from a pot into the ground, Tammy Sons, horticulturist and CEO of TN Nursery, always suggests transplanting them in the fall.
"The best time to transplant hydrangeas is in fall or early spring. Fall is the best time to plant anything because dormancy is approaching, and any kind of transplanting shock or stress the plant will have all winter to adapt and harden off before it starts its growth the following spring," she explains.
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When to Plant Hydrangeas by Zone
McDonald from Garden Girls says that regardless of what growing zone you live in, hydrangeas typically need six weeks of mild weather to establish strong roots. "Plant them in the spring once the danger of frost has passed. You can also plant in the fall when you are sure that the heat of summer is gone. Extreme temperatures, high or low, will put stress on hydrangeas and could affect future blooms," she explains.
Noyes explains that there is a difference in when you should plant hydrangeas according to USDA hardiness zones because the first and last frost days come at different times. Keep reading for the average frost dates and experts' advice on when to plant hydrangeas based on your gardening zone.
Zone 3
USDA Gardening Zones range from the coldest to the hottest. This zone covers a range of states such as Wyoming, Montana, Maine, and parts of Colorado. The lowest temperatures for zone 3 range from -40 and -30 degrees Fahrenheit.
In USDA zone 3, the first day of frost is between September 8 and September 15; the last day of frost is between May 15 and May 22.
Even though this zone has harsher winters, you can still have beautiful hydrangeas if you plant them at the right time. Noyes says no matter which zone you are in, you may want to keep on the safe side and plant your hydrangea a bit after the last day of frost, and well before the first day of frost.
Zone 4
This zone includes northern states of the U.S. and some parts of Alaska, so it also has frigid winters. The lowest temperatures for zone 4 run between -30 and -20 degrees Fahrenheit.
The first day of frost for this zone is between September 21 and October 7; the last day of frost is between April 21 and May 12. So, if you are opting for potted hydrangeas and spring planting, make sure to wait until after mid-May to prevent losing your precious plants.
Zone 5
This zone spans across the United States and includes states such as Virginia all the way to Alaska. The lowest temperature ranges between -20 and -10 degrees Fahrenheit. The first day of frost is between October 13 and October 21; the last day of frost is between April 7 and April 30.
"Most hydrangeas will only grow well in zones 3-9. Colder and very hot and dry zones are extremely difficult to grow in," Sons of TN Nursery explains. She says that when to plant depends on when dormancy starts. "For example, in the northern lower zones 3-5, dormancy (fall) season is 3-4 weeks earlier than in warmer zones. In zones 3-5, the best time to plant is in September," she says.
Zone 6
Zone 6 is the most expansive zone across the U.S. and stretches from parts of New York all the way to Oregon and even into parts of Alaska. The temperatures range from -10 and 0 degrees Fahrenheit. The first day of frost is between October 17 and October 31; the last day of frost is between April 1 and April 21.
So take Noyes' advice and plant a bit before the first day of frost if you are planting in the fall rather than the spring.
Zone 7
As you get into warmer climates, you have less time for frigid temperatures and a longer planting season. This zone covers a wide range of states from the east to the west coast. Some states included in this zone are Alabama, Georgia, Nevada, Oregon, Idaho, and Utah. In USDA zone 7, the first day of frost is between October 29 and November 15; the last day of frost is between March 22 and April 3.
The average winter temperature ranges between 0 and 10 degrees Fahrenheit. If you live in this zone, you can start planting earlier in spring and later in the fall.
Zone 8
If you live in a state within zone 8, you have a longer window during which you can plant hydrangeas. It covers states such as South Carolina, Texas, and even the Oregon coast. The lowest average temperatures range between 10 and 20 degrees Fahrenheit.
The first day of frost is between November 7 and November 28; the last day of frost is between March 13 and March 28. That means you can plant a bit later into fall because it doesn't frost until November.
Zone 9
States such as Arizona, Florida, New Mexico, Washington, and others in the warmer regions are found in this zone. It is in the top five warmest USDA zones, with the lowest average temperatures ranging between 20 and 30 degrees.
The first day of frost is between November 25 and December 13; the last day of frost is between February 6 and February 28. This is the shortest span between frost dates until you get into zone 10 and beyond.
Remember, McDonald says that you need roughly six weeks of mild weather when planting hydrangeas, so this zone offers warmer winter months, giving more time to plant.
Zone 10
In USDA zones 10 and above, there is no frost at all. Only a handful of states are in this zone, including Florida, Hawaii, Nevada, Texas, and a couple of other areas. For this zone, you may even be able to plant hydrangeas during winter.
Noyes says that it is actually a good idea to plant during winter in frost-free climates, because this way, you will make sure that the plant is dormant and that it has all the time it needs to settle in the new soil before it starts growing again.
"To avoid transplant shock, make sure that you keep as much of the original radical system as possible and water your hydrangea regularly till you see it has settled," she advises.
Frequently Asked Questions
Where should you not plant hydrangeas?
Noyes from Gardening Chores says you should never try to plant hydrangeas in zones 1 and 2 due to extremely cold temperatures. "Similarly, it is hard to grow hydrangeas in very hot areas of the country; their heat tolerance ranges from zones 8 and 11 (but it is usually 9), according to the variety. If you are at the upper end of the heat tolerance of your chosen hydrangea, plant it in partial shade rather than full sun."
She also stresses that you should never plant hydrangeas in poor quality soil or where it lacks sufficient drainage. They need soil that's fertile and well-drained.Should hydrangeas be planted in full sun or shade?
"Hydrangeas thrive in both full sun and partial shade conditions. However, in warmer climates, they tend to prefer the second, especially if they can be provided with some shade and coolness during the afternoon hours," Noyes says.
How do you prepare soil for hydrangeas?
Noyes advises preparing the soil with loam, clay, or sand-based soil, avoiding chalk, with loam being the optimal choice. "Regardless of the soil type, remember to enrich it with a generous amount of compost, steering clear of manure which could burn the roots. Incorporating coarse sand will help improve drainage," she advises.
Do hydrangeas need to be cut back for winter?
"No, you don't cut them back in winter. But you do need to prune them, if only to get rid of dry, ill, or rotting branches," Noyes says.
She advises pruning hydrangeas before the plant produces new buds and far before it opens any new leaves. Therefore, fall is the most suitable period for pruning because it is when the plant enters its dormant stage.Do hydrangeas like lots of water?
"Hydrangeas, far from being drought-tolerant, are always on the lookout for a good watering. Their verdant leafy mounds are telltale signs of their thirst. These plants do appreciate regular, moderate hydration, but remember, they're not fans of water-logging," Noyes explains
The larger the hydrangea, the greater its thirst. An adult plant's needs can span between 1 to 2 gallons of water per week, with seasonal heat being a decisive factor. You will water less frequently during the cold winter months. They also call for more frequent watering after transplanting.
