How to Grow and Care for Hydrangeas

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Hydrangeas are easy to grow, require little maintenance, and are adaptable to soil conditions.

The plant is a timeless classic and a gardener’s favorite. With so many varieties to choose from, it is possible to enjoy their magnificent floral display from spring through to the summer. And the best bit is that many of the species require minimal intervention on your part to do well. 

The majority of hydrangeas are grown as shrubs of varying sizes. But you can adapt the H. arborescens into a hydrangea tree by simply keeping one strong central  “trunk” and removing all other leaders. There is also the beautiful climbing specimen, the H. petiolaris which once established will reward you with long-lasting and vigorous blooms.

All commonly grown hydrangeas are perennial, deciduous plants and are primarily native to Asia and to a lesser extent to America. The flowering period ranges from late spring to fall. Faded blooms left on the plant at the end of the season will create additional interest and color.

The flowers and leaves of the hydrangea are toxic as they contain an ingredient which breaks down to produce cyanide, which is extremely poisonous. 

History

hydrangea flowers

The name Hydrangea is derived from two Greek words: hydro (water) and angos (vessel). It comes as no surprise therefore to understand that hydrangeas do need a lot of water to do well. 

Hydrangeas didn’t appear in Europe until the 18th century when a native North American variety was introduced. 

During the Victorian era, the flowers were considered ostentatious because they are so large and prolific. Sometimes they were given to women who were accused of being frigid!

In Japan, the hydrangea has enjoyed continued success and has been revered since the 7th century. Hydrangea blooms were offered to young women by the emperors.  

Plant Facts

Scientific nameHydrangea macrophylla, H. quercifolia, H.paniculata, H.arborescens
Common namesFrench hydrangea, hydrangea, hortensia
GenusHydrangea
FamilyHydrangeaceae, Saxifragaceae
Height3 m or 10 feet tall
Width3 m (10 ft)
USDA Plant Hardiness ZoneZones 3 to 7
Native toChina, Japan, Mexico, South & Central America
Blooming seasonSpring and through the Summer
Flower colorsPink, red, lavender, purple, blue, white
Plant specific featuresBeautiful show of large flowers
growing hydrangeas

How to Plant and Grow Hydrangeas

Correct planting is the single most important part of growing hydrangeas. Getting it right will give the plant a good start in life, and you will reap the benefits with the annual blooms in your garden. There are three things to consider when planting a shrub such as a hydrangea – choosing the best site, preparing the soil for planting, and putting the plant into the ground.

You may wish to plant a single specimen plant, or a hedge of hydrangeas. You can even plant a single plant in a pot, although it needs to be a large pot to accommodate the root expansion.

If at all possible, don’t plant hydrangeas in pots because they won’t do nearly so well. If space is tight, it is much better to choose one of the smaller hydrangea species (dwarf hydrangea varieties) that will not overwhelm your available space.

Hydrangeas are an easy, non-demanding plant to grow, but to get the very best from your plants, you should follow the tips in the section below.  

planting hydrangea

Where to Plant Hydrangeas

To get the best from your hydrangea, choosing the best planting site is essential. Have a look around your garden and see if you have a suitable spot where they will be able to enjoy the warmth of the early morning sun but not be baked by the afternoon heat. 

So you need a location which quite probably will be on the north-facing side of your home. It should be sheltered from cold, damaging winds that can burn both leaves and flower buds. 

Existing trees with well-established root structures will be able to absorb water and nutrients far better than your newly planted hydrangea, so avoid planting under or too close to existing trees.

If you have selected one of the grander varieties, this will grow and quickly too! So you need to make sure that where you have decided to plant your hydrangea, there is sufficient space to accommodate the growing plant. 

Because hydrangea bushes lose their leaves during the winter, you may wish to plant them next to an evergreen shrub in order to retain some green leaf interest during winter. 

hydrangea bush

When to Plant

As with many shrubs, the fall is the best time to plant hydrangeas. Planting in the Fall enables the plant to become established and develop its roots before winter arrives, and the plant stops growing. A healthy and well-established root system will give the plant the ability to absorb essential nutrients and moisture from the ground to enable it to flower well once it bursts into life the following spring. 

If it isn’t possible to plant in the Fall,  then the early spring is a viable alternative. Once again, there is time for the roots to grow before the plant starts to flower.

Planting should take place once the danger of frosts has passed. However, spring planting can be risky for a new hydrangea if there are late frosts or cold winds as they can stress the plant, stunt its growth and reduce subsequent flowering. So be prepared to provide a bit of protection around a spring-planted hydrangea if inclement weather is predicted.  

Ideally, plant late in the afternoon when temperatures have cooled. This will help to retain the moisture around the newly planted hydrangea. The soil around the new plant must be kept damp until it has established a strong and healthy root system. Until then, the plant can’t seek out moisture from deeper in the ground.  

How to Plant

It’s very easy to plant hydrangeas. You just need to dig holes that are 2 feet (0.61 m) larger than the roots in the pot or the root ball if the plant is bare-rooted. The hole needs to be larger than the roots to give the roots a bit of help when they first start to grow. Backfill the hole around the roots of the plant with soft soil or compost.

The depth of the hole should be approximately the same as the root ball, so the plant is just a little higher than the soil. This will aid the drainage from around the plant.

hydrangea bush care

See more: Transplanting hydrangeas and propagating hydrangeas

Hydrangea Bush Care and Maintenance

Here are some important hydrangea care tips:

Soil

The basis for good growing conditions lies in the growing medium in which your plant is going to grow. Hydrangea bushes like well-drained soil, enriched with plenty of organic matter.

Good drainage is essential as hydrangeas are not tolerant of being in waterlogged, heavy, or poorly draining soil. Their roots will rot in just a few weeks, and you will have lost your plant.

If you do have heavy, clay soil, then you need to improve the quality and condition of the soil before planting with an abundance of compost. A mulch placed at the plant’s base helps to keep the soil around the roots moist and cool.  

One of the wonderful things about certain types of hydrangeas (the H. macrophylla) is that you can change the color of the blooms by adjusting the pH (acidity) of the soil. The more acid the soil, the bluer the flowers and with an alkaline soil, the flowers will be pink. You can’t change the color of white varieties though, their flowers will always be white whatever the soil pH level.

hydrangea plants

Water

During the flowering season, the plants should be kept well watered. Frequent watering is essential and this needs to be of a sufficient quantity for the plant to be able to continue to expand its root system. 

It doesn’t matter which variety of hydrangea shrub you have, all varieties need consistent and adequate watering. 

An easy way to make sure your plant has received ample moisture is to use a soaker hose, and this will also help to keep the water off the leaves and flowers. 

On hot days, the hydrangea bush is prone to wilting from the effect of the heat on its foliage. By providing ample watering in the early morning on hot days, you will help to reduce this wilting. 

A good way to retain moisture levels around the base of your plants is to apply a mulch under the hydrangea. As well as reducing moisture loss, the plant will keep cooler too. You can use grass clippings, straw, newspaper, well-rotted compost, or any organic matter as the mulch.  The benefits of using organic mulch over plastic or old carpet, are that the organic material will break down over time and provide additional nutrients for the hydrangea, as well as improving the condition of the soil. 

Make sure that the hydrangea shrub receives a  thorough watering at least once a week, and more frequently during spells of extreme heat.  

white green hydrangea

Fertilizer

Although by no means essential, hydrangeas will benefit from a specialist fertilizer application. Check carefully that the fertilizer is designed for your variety. Hydrangea varieties have different needs in both the quantity and composition of the fertilizer. 

The macrophylla varieties will appreciate monthly fertilizer applications during the growing and flowering season.  

Other varieties benefit from just one or two applications of fertilizer, which should be applied during spring and summer.  

Sunlight

The hydrangea needs some sunshine to do well but also appreciates shade. By providing a planting site that receives morning or perhaps late afternoon sunshine is ideal. 

The most important consideration is to protect your plant from searing heat at the height of the day.  Hydrangea bushes do not like too much heat and will wilt if exposed to direct sunshine during mid afternoons in the summer.

hydrangea pruning

Pruning

The most commonly grown types of hydrangeas with the large, showy blooms are the mophead and the lacecap (H. macrophylla). 

Pruning is very important to many varieties of this plant. Delaying this process will cause hydrangea not blooming.

Pruning hydrangeas needs to take place at the end of the summer, once the flowers have finished. This is because next year’s flowers will be formed on new wood. So the plant needs to have time to develop this new growth before the period of dormancy begins.

To prune, cut off the faded blooms and then remove any dead branches. Finally, cut back and thin out the hydrangea.

A climbing hydrangea (H. peliotaris) doesn’t need pruning unless you need to tidy up or control the growth of new shoots.

The oakleaf hydrangea (H. quercifolia) and the hydrangea “tree” (H. arborescens) develop their blooms on old wood. These types should be pruned in the early spring. To carry out the pruning of these types, you should deadhead hydrangeas and then cut back the plant.  

Pests and diseases

hydrangea leaves turning brown

Hydrangea shrubs are not plants that suffer unduly from pests and disease. Modern cultivars often have integral resistance.

Nevertheless, fungal disease, wilt, brown spots on leaves and mildew are all potential threats to the health of your plants.

If you do have a pest issue, the likely culprits are aphids and red spider mites. The most likely reason that you will have a problem with pests with your hydrangea plants is if they become stressed. 

Stress can be caused by a prolonged spell of poor weather or watering inconsistencies. Prevention is better than cure, and good care for your plants is always the best course of action.

Temperature and Humidity

A period of cool weather with temperatures not exceeding 18 °C and lasting around two months is essential for the production of flower buds. The hydrangea plant is not tolerant of frost and shouldn’t be subjected to temperatures below 4 °C. Different species can successfully overwinter in USDA hardiness zones between 3 and 8.

Although the plant shouldn’t sit in wet soil, it does require plenty of humidity. Copious and frequent watering is essential.

Preserving Hydrangea Flowers

small purple hydrangea

The gorgeous blooms of the hydrangea flowers will make you want to keep them all through the year. The good news is that you can preserve the flowers by drying them so that you can enjoy them during the dark winter days. There are several methods for drying the blooms, which vary in complexity.

However, the best dried blooms will be obtained when they are picked at the correct time.  Timing is far more important than the drying method used. Leave the flowers on the plant to dry naturally.  

The colors will fade, but if you try to cut them when they are in full color, you will be disappointed with the results. The result of naturally dried hydrangeas will give you a super, vintage look as the petals age and take on hues of deep red and pink. 

If you are determined to have dried blooms which have a fresh color, then use silica gel to dry freshly cut flowers.  

Other Uses for Hydrangeas

Although the roots and the rhizome of the hydrangea are sometimes used to treat urinary tract and kidney infections as well as certain pollen allergies, it is essential to seek professional, medical advice before ingesting any parts of the plant. The flower buds, flowers and leaves should be avoided as they contain a compound which decomposes to produce cyanide.

Despite this, certain Buddhists believe in the hydrangea’s health benefits. They produce an infusion made from the leaves of hydrangeas, drinking the tea which is produced.

purple green hydrangea

Types of Hydrangeas You Can Grow

There are many hydrangea types you can choose, we recommend these common and beautiful varieties:

Conclusion

It is not surprising to learn that given its beauty and majesty, the hydrangea flower has become a revered and much loved plant. Pink blooms are a frequent choice for wedding flower arrangements. Large white flowers are much loved by florists and used to create spectacular floral displays.

One thing is certain, due to its size, sweet smell and color variations, the hydrangea will always leave a lasting impression. Everyone will be impressed by the blooms, whether displayed in your garden, a container or as a cut flower in a vase.

See more: Hydrangea Flower Meaning and Symbolism