Hydrangeas grow up to be really large plants, so it is not advisable to place them very close to each other.
As a general rule of thumb, you should plant Hydrangeas at a distance of one foot more than the width of one plant.
Here is a quick look at how far apart you should plant some of the popular Hydrangea varieties.
| Name of Hydrangea | Width | Recommended Space between Hydrangeas |
|---|---|---|
| Big Leaf Hydrangeas | 6 to 10 feet | 7 to 11 feet |
| Endless Summer hydrangea | 3 to 5 feet | 4 to 6 feet |
| Edgy Hearts hydrangea | 2 to 4 feet | 3 to 5 feet |
| Mountain hydrangea | 2 to 4 feet | 3 to 5 feet |
| Hydrangea paniculate | 6 to 12 feet | 7 to 13 feet |
| Limelight hydrangea | up to 8 feet | 9 feet |
| Little Quick Fire & Strawberry Sundae | 3 to 5 feet | 4 to 6 feet |
| Smooth hydrangeas | 3 to 5 feet | 4 to 6 feet |
| Invincibelle Wee White | 30 inches | 40 inches |
| Oakleaf hydrangeas | 6 to 8 feet | 7 to 9 feet |
| Climbing hydrangeas | 5 to 6 feet | 6 to 7 feet |
How Far Apart to Plant Bigleaf hydrangeas
Bigleaf hydrangeas are also known as mophead Hydrangeas or Hydrangea Macrophylla. Compared to other varieties, this plant is medium in size.
The size of the Big Leaf Hydrangeas variety ranges from 6 to 10 feet. Accordingly, the distance between two plants of bigleaf hydrangeas should be 7 to 11 feet.
The Endless Summer hydrangea is a type of bigleaf hydrangea. This plant spreads 3 to 5 feet, which is quite less than most other plants in the Hydrangea variety. Therefore, the distance between these two plants should be 4 to 6 feet.
The Edgy Hearts hydrangea is one of the smallest types of Hydrangea Macrophylla. It only grows 2 to 4 feet. Being so small in size, the distance between two plants of this variety should be 3 to 5 feet.
Mountain hydrangeas
Mountain hydrangea, or hydrangea Serrata, is one of the most common species of hydrangeas. This plant reaches 2 to 4 feet in width. Therefore, the distance between two plants would be 3 to 5 feet.
This is one of the most compact varieties, which is why it is quite popular.
Panicle hydrangeas
Panicle hydrangeas, or hydrangea paniculate, is the largest species of hydrangea. This plant needs a lot of space around when you decide to plant it.
Hydrangea paniculate can reach anywhere between 6 to 12 feet in width. The distance between the two plants will need to be 7 to 13 feet depending on the size.
However, panicle hydrangeas have different varieties that range vastly in size from one to another.
The limelight hydrangea spreads up to 8 feet wide, so this variety needs to be planted at least 9 feet apart from each other.
Little Quick Fire and Strawberry Sundae, on the other hand, are some of the smallest varieties of panicle hydrangea. They grow 3 to 5 feet in width. So, the distance between these two plants should be 4 to 6 feet.
Smooth hydrangeas
Smooth hydrangeas are fairly small in size. They spread 3 to 5 feet in width. For the plants to have enough space between them, you need to plant them at a distance of 4 to 6 feet from each other.
Annabelle hydrangea will need slightly more space, at least 7 feet away.
The Invincibelle Wee White is one of the most compact varieties of smooth hydrangeas. It only spreads up to 30 inches in width. So, you can plant these hydrangeas 40 inches away from each other.
Oakleaf hydrangeas
Oakleaf hydrangeas extend 6 to 8 feet wide. To plant them next to each other, you will need to keep a space of at least 7 to 9 feet between two plants.
Climbing hydrangeas
Climbing hydrangeas grow upwards. That is why they do not need a large area when they are planted. You can keep a distance of 7 feet between climbing hydrangeas and other plants.
It doesn’t matter even if the plant is close to other plants, as it will grow only upwards. Also, ensure that you provide an external frame for the plant to grow properly.
What happens if you plant hydrangeas too close together?
If you plant your hydrangeas too close to each other, it can cause problems over time.
Fungal diseases
When you plant your hydrangeas too close together, it will restrict the movement of air among the shrubs. Without proper air circulation, the plant may not dry properly and can remain damp.
As a result, it gets easier for fungal diseases to develop on the leaves and branches of the plant.
Lack of moisture
Hydrangeas are plants that like moist soil. They are large plants with large leaves, so the water also evaporates faster, which is why they always need the soil to be moist.
However, if the plants are too close together, they will have to compete for moisture. This can result in the plants withering or even dying if the weather is too hot.
Smaller and fewer flowers
Just like competing for water, the hydrangeas will also have to compete for nutrients from the soil when they are planted too close together.
The soil can only provide so many nutrients, and the plants will not get sufficient nutrients. As a result, the number of flowers during the blooming season will be less, and the size of the flowers will be small.
What to do if you have planted your hydrangeas too close together?
Here are some steps that you can take if you have already planted Hydrangeas too close to each other.
Regular Pruning
If your plants are already planted too close together, one thing you can do to free up space is to prune your hydrangeas every year.
Prune the hydrangeas during the appropriate season according to the variety of hydrangea that you have. Remove the side branches to reduce the diameter of the hydrangea.
Prune the branches to the ground level so that they do not grow back. Also, do not remove more than one-third of the branches, or else the plant might get stressed.
Water more often
If your hydrangeas are planted too close together, you will naturally need to water the plants more frequently.
Check the moisture of the soil near the plants at least 2 inches inside the soil. When hydrangeas are planted too close, they will retrieve water from deep inside the ground.
So, sometimes the soil on the surface may appear moist, but underground, it could be dry. Water the hydrangeas as often as needed just so that the soil remains moist, but does not get soggy.
Use fertilizers
You will need to fertilize your hydrangeas to get good blooms. You can use slow-release fertilizers that have a high phosphorous content. This will ensure that your flowers grow large in size.
Transplanting
The above solutions can work well and you will be able to grow your hydrangeas in a compact space for a while.
But if none of the solutions work, the only option left would be to transplant your hydrangeas in a way that they are all appropriate distance away from each other.
How far to plant hydrangeas from the wall of your house or a fence?
If you are okay with your plant leaning on the walls of your house, you need to plant your hydrangea at a distance of at least half the width of the plant when it grows to its maturity.
For example, if your plant grows 6 feet wide, you need to plant it at least 3 feet away from the house.
To keep a gap between the wall and your hydrangea, add another foot. This will avoid the plant from shading the house and there will be less moisture on the walls as well.
Hydrangeas should preferably be planted on the east side of your house. This is because hydrangeas enjoy the morning sunlight and then prefer partial shade.
You can plant the hydrangeas on the west side of the house as well, but it could work well only for panicle hydrangeas.
Avoid planting your hydrangeas on the north and south sides of the house.
The plants will get very little light on the north side of the house and may not flower well as a result.
On the other hand, the south side will get too much sun and it will cause the soil to dry out quickly, as well as causing the plant to wither and burn.
Hydrangea hedges
Hydrangea hedges have become a popular idea among gardeners. Their hedges act as a border for the garden, building privacy, but at the same time creating a stunning visual of hydrangea blooms.
A lot of varieties of hydrangea do not grow very tall, but they establish themselves quickly and easily as hedges. Hydrangea hedges are also a great attraction because the blooms are beautiful and come in a range of colors.
How far to plant hydrangeas for hedges?
If you are planting hydrangeas in rows to make hedges, you need to plant them at a distance of the width they reach maturity.
For planting hydrangea plants normally, it is recommended that you plant the hydrangeas an extra foot apart from their width so that they have enough space to grow.
But for hedges, you need your plants to be grown very close together. So in this case, you do not need to add the extra foot. You can plant your hydrangeas at a distance of their width.
Prune your hydrangeas slightly every year to keep your hedge in shape.
Water them regularly on time. Provide plenty of water.
Use fertilizers for the hedge as well and treat the plants immediately when there is an issue.
How to plant a hydrangea hedge?
Once you select the hydrangeas you want to grow on your hedge, the rest of the procedure is simple.
Firstly, decide the spacing of the hydrangeas according to the species you have. Too much spacing between two plants can cause the hedge to look very sparse and empty.
Once you plant your hydrangeas accordingly, you can use drip irrigation to water your plants. Hydrangeas will need constantly moist soil, so you can water the plants at regular intervals so that the soil never gets dry.
Once the plants bloom, you will have a beautiful hedge of colored hydrangea blooms.
