Hydrangeas include both deciduous and evergreen varieties that are native to the America’s and Asia with over 75 different species most being found in Asia.
Depending on the variety, they will need to be planted 3 – 10 feet apart and most varieties are between three to ten feet tall with the tallest being around 100 feet tall.
These shrubs are well known for their immensely large abundant blooms and versatile uses with differing foliage and blooms.
They are woodland and mountain shrub that do well in most soils, they are happy in both full sun and partial sun but may take longer to grow with fewer blooms.
If planted in full sun, they will require more water during the hot summer days.
Hydrangeas are fasting-growing shrubs that can grow more than two feet in a single growing season.
PLANTING HYDRANGEAS
Hydrangeas are best planted in the early spring or fall in hardiness zones 5 through 9 in well-drained soil with a pH range between 5.0 through 6.5.
When planting hydrangeas, it is best to dig a hole at least double the width of the root ball.
Using a hand trowel or garden knife, break up the bottom of the root ball, then mix some compost with the soil before filling in the hole.
After planting mulch should be added to help hold moisture in the soil.
FERTILIZING AND WATERING
Hydrangeas are best fertilized with a slow-release fertilizer that is meant for trees and shrubs once a year is the simplest solution.
Another way is to use an all-purpose fertilizer in March, May, and July or a homemade liquid fertilizer.
When applying fertilizer, it is best to apply it between the base of the plant to the tips of the branches. This area of the plant is known as the drip line.
It is best to give them around one inch of water per week and they become drought-tolerant when they are well-established.
MULCHING
Mulching hydrangeas will help the soil retain water which will reduce the amount of time it takes to water them.
The thickness of the mulch is best around 2 inches deep which will also help to prevent weeds from growing around your hydrangeas.
It is best to add new mulch every year as the older mulch breaks down.
BLOOMS
Their blooms appear in spring to early summer depending on the variety and stick around until the first frost with flower clusters that are up to 10 inches wide.
Their blooms are available in blue, red, purple, green, and white which attract butterflies and bees.
They typically contain two types of blooms, the first has small fertile blooms that are in the middle of the flowerhead. The second flower is a large sterile showy bloom with large sepals.
The pH of the soil will cause the color of the blooms to change color if you wish. Soil with a pH above 7.0 creates pink and red blooms.
Soil pH between 6.0 and 7.0 creates purple or bluish-pink blooms.
Adding aluminum sulfate or sulfur will decrease the pH of the soil while using lime will increase the pH of the soil.
Please take note that hydrangeas that produce white blooms can’t change their color with the pH of the soil.
Deadheading is the method of removing the dead blooms before it goes to seed. This will cause the shrub to produce more blooms in an attempt to produce seeds.
HOW TO PRUNE HYDRANGEAS?
Any new growth with blooms should be pruned back during the late winter or early spring before it comes out of dormancy.
In the spring, if there is any dead or damaged growth then it should be removed.
Any stems that have wildly grown much higher than the rest of the plant which is known as leggy growth should also be removed.
The older growth should be pruned back during the summer months after blooming.
When pruning, remember that the main stem that comes from the ground needs to be thick and strong enough to help support the weight of the plant.
Therefore it is not recommended to prune them too early and often.
When the main stems that come up from the ground start to produce fewer blooms then it is time to remove the stem just above the ground.
This will promote new growth but don’t remove more than one-third of the stems.
PROPAGATING
Propagating hydrangeas is done with four methods. The first method works best with varieties such as bigleaf and panicle hydrangeas.
The second method works best with varieties such as oakleaf and smooth hydrangeas.
The first is done by digging a small trench next to the shrub and in the direction you want new plants.
With a branch remaining on the shrub, lower it into the trench with 6 to 12 inches sticking out of the ground.
Scratch the bark of the branch where it will be making contact with the soil.
Replace the soil, water the area, and place paver stones, bricks, or stones on top to help hold in moisture.
The second method is done by removing a section of new green growth then dipping the cut section in water then root tone and wrapping the cut section with a paper towel.
The third method is to simply pull out some new growth from the underground stem by digging up the new growth and separating it from the main shrub.
The last method is to allow some blooms to go to seed, harvest them, dry and store them for sprouting the following growing season.
OVERWINTERING
Hydrangeas are hardy shrubs that are able to survive in temperatures as low as -10 degrees Fahrenheit.
Insulating your hydrangeas during the winter months should start in hardiness zones of five and above.
This is done to protect the shrub from freezing with a layer of mulch that is 3 to 5 inches thick to protect the roots from the cold winter temperatures.
If needed chicken wire, wood stakes, or small metal fence posts and baling wire can be used to encircle the plant before adding the mulch.
The mulch can be a mixture of leaves, pine straw, sticks, and wood chips if you want, but it doesn’t have to be completely wood chips if you want.
In hardiness zones above six, they don’t require any extra mulch for winter protection and if you don’t use mulch there still is no need to do anything.
If you have potted hydrangeas then it is best to bring them into a garage or indoors for the winter.
PESTS
For hydrangeas, pests are rarely an issue but it is something to watch out for if you see holes or brown spots.
DISEASES
Most plant diseases that affect hydrangeas are fungal based therefore extended high humidity with poor air circulation will create a breeding ground for a fungal breakout.
Taking preventive measures is the best way to deal with fungal issues when the conditions are right for them to flourish.
- Powdery mildew
- Leaf spot
- Bud blight
- Bacterial wilt
- Rust
VARIETIES
There are around 75 different species of hydrangeas with six species that are typically grown by gardeners.
BIGLEAF HYDRANGEA
Bigleaf hydrangea is a deciduous shrub where it is native to Japan and is the most popular variety of hydrangeas that is divided into two groups.
Hortensias have a large cluster of blooms and lacecapes have a flat top on the large cluster of blooms with non-showy blooms at the center which are fertile.
- Shrub size – grows to about 10 feet tall and 10 feet tall
- Spacing – 6 to 10 feet apart
- Drought tolerant – yes
- Blooming colors – Pink and blue blooms that appear in early spring and last until mid-summer
- Foliage – green spade-shaped leaves with jagged edges
- Deer resistant – no
- Also known as – French, Japanese, and snowball hydrangea
OAKLEAF HYDRANGEA
Oakleaf hydrangea is a deciduous shrub that is native to the Southeastern U.S. as a woodland shrub.
During the fall, their green oakleaf-shaped leaves turn shades of red, purple, and bronze.
- Shrub size – grows to about 8 feet tall and 8 feet wide
- Spacing – 4 to 8 feet apart
- Sun requirements – partial shade with morning sun
- Soil pH – 5.0 through 6.5
- Drought tolerant – yes
- Blooming colors – white blooms that age into red or pink blooms that appear in early spring and last until mid-summer
- Foliage – oak leaf-shaped leaves
- Deer resistant – no, but this variety is more deer resistant that other varieties
PANICLE HYDRANGEA
Panicle hydrangea is a deciduous shrub that is native to Japan and China where it is one of the most winter-hardy and more droughts tolerant hydrangeas.
They are an easy-to-grow shrub that is one of the coldest and heat-tolerant hydrangea varieties.
- Shrub size – grows to about 20 feet tall and 8 feet wide
- Spacing – 6 to 10 feet apart
- Sun requirements – partial shade with morning sun
- Soil pH – 5.8 through 6.2
- Drought tolerant – yes
- Blooming colors – red, pink, green, and white blooms
- Foliage – oval-shaped green leaves with jagged edges
- Deer resistant – no
- also known as – limelight hydrangea, hardy hydrangea, and peegee hydrangea
SMOOTH HYDRANGEA
Smooth hydrangea is a deciduous shrub with wide branches that is native to the Eastern U.S.
Their blooms open with a lime green color, transform to a creamy white color, then transform into a tan color in the fall.
- Shrub size – grows to about 5 feet tall and 6 feet wide
- Spacing – 3 to 5 feet apart
- Sun requirements – partial shade with morning sun
- Drought tolerant – yes
- Blooming colors – pink, green, and white blooms that appear in early summer and last until the first frost.
- Foliage – wide oval-shaped green leaves with jagged edges
- Deer resistant – no
MOUNTAIN HYDRANGEA
Mountain hydrangea is a deciduous shrub that is native to Japan and Korea where it has evolved to live in mountainous areas.
Because they stay in a dormant stage for a longer period of time, they bloom later than most other varieties, and they are more winter-hardy than most other varieties.
- Shrub size – grows to about 4 feet tall and 4 feet wide.
- Spacing – 2 to 4 feet apart
- Sun requirements – partial shade with morning sun
- Drought tolerant – yes
- Blooming colors – blue and pink blooms
- Foliage – oval-shaped green leaves with jagged edges
- Deer resistant – no
CLIMBING HYDRANGEA
Climbing hydrangea is native to Asia and is a vine, therefore using a trellis is recommended.
- Shrub size – grows to about 40 feet tall and 2 feet wide
- Spacing – 5 to 10 feet apart
- Sun requirements – full sun to partial shade
- Drought tolerant – yes
- Blooming colors – white blooms
- Blooming time – blooming starts in late June to early July depending on the climate and lasts until the first frost
- Foliage – oval-shaped green leaves with smooth edges
- Deer resistant – no
LESSER KNOWN VARIETIES
Hydrangeas are probably the most popular shrub used in gardens and landscaping but most varieties are overlooked or unknown.
LITTLE LIME HYDRANGEA
Little lime hydrangea is a dwarf variety of panicle hydrangea that can grow in potting containers.
Their blooms start with a green color and transform into a pink color in the fall.
- Shrub size – grows to about 4 feet tall and 4 feet wide
- Spacing – 3 – 5 feet apart
- Sun requirements – full sun to partial shade
- Drought tolerant – yes
- Blooming colors – white blooms
- Foliage – oval-shaped green leaves with smooth edges
- Deer resistant – no
ENDLESS SUMMER CRUSH HYDRANGEA
Endless summer crush hydrangea is a low-growing shrub that can do quite well growing in containers.
This shrub is a variety of bigleaf hydrangea and does best with morning sun and afternoon shade.
- Shrub size – grows to about 2 feet tall and 3 feet wide
- Spacing – 18 to 24 inches apart
- Sun requirements – full sun to partial shade
- Drought tolerant – yes
- Blooming colors – intense pink, purple, or red-colored blooms that appear in early spring and will rebloom until the first frost
- Foliage – oval-shaped green leaves with jagged edges
- Deer resistant – no
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