The size of the flower heads, alone, make hydrangeas a favorite perennial among gardeners. Hydrangea care involves control of sunlight, adequate moisture and proper pruning. These tips for growing hydrangea bushes will help you get the most out of your plants.
Cottage gardeners love the huge hydrangea flowers which have a lovely old fashioned charm. Fortunately, hydrangeas are easy to grow and are a trouble free plant in the garden.
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Types of Hydrangeas
Hydrangeas come in shrubs of all sizes and also in climbing styles. There are some dwarf varieties that are perfect for smaller garden spots. The plant grows from a rhizome, and this root is used to make medicine.
Hydrangea macrophylla or bigleaf hydrangea is the most commonly grown hydrangea plant. It has many different cultivars and two groups: mopheads (globe shaped flowers) and Lacecaps (flattened flower heads.)
The plants will grow to 10 feet tall in zones 6-9. They have very showy flower heads with loads of summer color and interest.
If you don’t have the room for a full sized hydrangea shrub, there are some dwarf hydrangea varieties available.
Most are hardy in zones 5-9 but will not grow much taller than 3 feet. Some varieties are:
This variety of hydrangea can grow in drier soil and does not like wet feet. The plant is a dramatic blooming variety with four seasons of interest. The flowers of oak leaf are often white but come in other colors too.
The plant gets its name from the shape of it’s large leaves which will turn brilliant colors in the fall months. Some varieties are:
Hydrangea bushes can get to be quite large and many people don’t have room for this size of plant in their gardens. You can still enjoy the lovely flowers by growing climbing hydrangeas. They are native to the woodlands of Japan.
This woody vine grows throughout the USA in zones 5-9. Climbing hydrangeas can grow up to 60 feet tall (or even taller)if let untrimmed, so regular pruning in necessary to keep it under control.
Even though they are larger, they have a smaller footprint.
Hydrangea paniculata, also known as panicle hydrangea can be grown to look like a small tree. The plant branches fairly low to the ground and sometimes has multiple trunks.
Be sure to check your hardiness zone if you want to grow this plant. Tree hydrangeas are cold hardy only in zones 5 through 8a. They can grow to a height of 25 feet high and become 20 feet wide.
Deer resistant hydrangeas
Nothing is worse that having your favorite plants ravaged by nibbling deer. Fortunately there are a few deer resistant varieties of hydrangeas. Some popular ones are:
- Oakleaf hydrangea – hydrangea quercifolia (white flowers, both dwarf and regular sized cultivars.)
- Climbing hydrangea – Hydrangea anomala petiolaris because the vines grow upward, they are taller than most deer can feast on.
Hydrangea Care Tips
Soil and planting needs for hydrangea bushes
Hydrangeas love a well draining soil that has been enriched by adding organic matter, such as compost. When planting, add a handful of organic matter to the planting hole and fill it with water.
Make sure the planting hole is the depth of the root ball and about 2-3 times as wide to give the roots room to spread out. Space hydrangea bushes 3-10 feet apart, depending on the variety, since most hydrangea bushes get quite large.
Sunlight needs for hydrangeas
Hydrangeas prefer relief from the hottest rays of the sun in the afternoon. An ideal spot is one which gets ample morning sun but afternoon shade.
They can also tolerate a shady spot for most of the day and will still flower, although not as profusely as a spot which gets morning sun. The photo above shows a hydrangea planted on the north side of our house which gets very little sunlight but still flowers well.
During the first few years after planting hydrangeas, be sure to keep hydrangeas well watered. The leaves wilt easily if the soil is too dry.
Once established, they are more drought tolerant, although I have found that I need to add extra water in the hottest days of summer.
If you took care to add compost or other organic matter at planting time and yearly in the spring, your soil will be fertile and the hydrangeas will probably not need additional fertilizing.
If your soil is sandy, you can use all an all purpose fertilizer in late winter or early spring. Be careful of too much fertilizer, or you will end up with a hydrangea which has lots of lush leafy grown and few blooms.
Cold Hardiness Zones
Most hydrangeas are hardy in zones 5-9. A few varieties can take the cold to as low as zone 3.
If you get a lot of snow, cover the plants to a depth of 18 inches with bark mulch, pin needles or straw to protect it from the cold.
Hydrangea bloom time
Most hydrangeas bloom in early summer in the Southern areas, and in mid summer to early fall in the Mid West.
Panicle hydrangeas bloom from late spring to early summer but keep their blossoms on the plant until late fall or early winter, when they shatter.
Size of hydrangea plants
The size of your hydrangea bush will depend on the variety that you have planted. Dwarf varieties usually top out at 3-4 feet, and normal big leaf hydrangea bushes will grow to about 10 feet tall and wide if left unmanaged.
The tree form of hydrangea (panicle hydrangeas) are the largest variety and will grow up to 25 feet tall.
The flowers are also usually quite large. My big leaf hydrangeas routinely get flower heads that are at least 10 inches wide and are just magnificent.
When should hydrangeas be pruned?
Tips for pruning hydrangeas
Pruning hydrangeas will make the shrub more manageable in size. It can also make for a more vigorous plant and can increase the size of the already large flowers.
Most hydrangeas are best pruned in the summer months after the plant has bloomed. The buds for next years plants start out on old wood and these set in late summer and early fall.
If you prune the plant after those buds have set, you’ll be cutting off next year’s blooms.
Old wood stems have been on the plant since the previous summer. New wood are those that develop during the current growing season. The exception is the variety known as Endless Summer.
This type produces flower buds on both old and new wood. It will bloom in early spring and then again later on new wood. Cut off faded flower stems to encourage new growth and new buds. Then prune after the last blooms fade in the fall to control the size and shape of the plant.
How much to prune?
If you are trying to just tidy up the plant, simply remove the old blooms. Just snip them off below the flower head. You can also remove any straggly looking canes at the soil line.
When a hydrangea gets old and has mainly woody canes, it will produce smaller blooms. To make for a more vigorous plant, regular removal of a few of the oldest canes will encourage lots of new growth and will result in larger flowers.
Removing old canes will also help in keeping the overall size of the hydrangea bush under control. Simply remove the tallest canes, in this case.
Any flopped over canes should be removed to make sure the base of the plant is stable and secure. Flopped branches will tip root if not removed.
Climbing hydrangea pruning
The best time to prune a climbing hydrangea is late summer when the vine has finished flowering.
You can trim the vine to control either (or both) its height or its width. To prune a climbing hydrangea, remove dead branches and make pruning cuts at the leaf nodes so that it will encourage the plant to fill out and become more bushy.
Trimming just above the leaf node will make the plant to branch out at that just below that point, making the vine look fuller and more lush.
If the vine has become damaged or very woody, heaving pruning may be necessary. This is best done in early spring. For heavy pruning, trim back most of the vine to about 3-4 foot lengths. You will lose flowers that year but the plant will be better long term.
Propagation of Hydrangeas
The most common method of propagation is from cuttings. There are a few ways that this can be done. The best time to take cuttings is in the spring.
Growing Hydrangeas from cuttings
Cuttings of hydrangea will root easily in soil, water, or from the tips of the plant if they touch the ground and start to root, which happens naturally in nature.
Whichever method you try, be sure to take cuttings from thick, fleshy stems just above the leaf node. (area where the leaf attaches to the stem.)
Most of the leaves will be removed to allow the stem to devote all its energy into producing roots, rather than maintaining the stem.
Roots will develop in 2-3 weeks and you can then plant the rooted cuttings in potting soil.
Air Layering and Tip Rooting Hydrangeas
Two other methods of rooting cuttings are air layering (rooting the plant as an aerial shoot while it is still attached to the mother plant) and tip rooting (allowing the tip to come in contact with the ground so that it will root.
Both of these methods allow the cutting that is rooting to receive nourishment from the mother plant, since is not removed from it.
Can you grow hydrangea from seed?
Even though cuttings are the most commonly used ways to propagate hydrangeas, they will also grow from seed. You can purchase hydrangea seed from your local gardening center or collect your own.
The seeds of hydrangeas are found in the the flower heads. The best time to collect them is in the fall when the flowers are dying off.
Hydrangea seeds are very tiny and look almost like dust.
When a hydrangea has become very large and overgrows its spot in the garden, you can divide the root ball into two sections and remove one to plant in another area of your yard.
Both plants will take a few weeks to send out new growth and extra watering is necessary during the period of time when they are recovering.
Divide hydrangeas in the early spring or late fall.
Uses for hydrangeas
The blossoms of hydrangeas are very large and one bloom can look fabulous as a cut flower in a vase.
Hydrangeas make a great focal point in a garden bed. Their showy flowers and lush, green flowers make a great back drop for smaller plants and perennials. Be sure to place it in the middle of large beds, or at the back of smaller beds.
Rows of hydrangeas can easily cover an unsightly chain link fence if you plant them every 3 feet or so along the perimeter.
Plant hydrangeas along the edges of a drive for a relaxing entry to a property.
Hydrangea Macrophylla, the bluish-bloomed flowering hydrangea is used for its aesthetic and health-promoting qualities.
Many of the popular hydrangeas are only cold hardy to zone 5, so enjoying the beautiful flowers farther north can be a challenge. There are some varieties that do will in colder zones though.
- PInky Winky Panicle Hydrangea – Zones 3-8
- Annabelle Smooth Leaf Hydrangea – Zones 3-9
- Little QuickFire Dwarf Hydrangea – Zones 3-9
Colors of hydrangeas
We tend to think of hydrangeas as either pink, blue since the two colors can change in a garden, or white which never changes.
But hydrangeas come in a wide range of colors from the well know blues and vibrant pinks lavender, and rose colored blooms. It is even possible for one hydrangea plant to have more than one color bloom on it!
- Hydrangea Endless Summer – These are repeat blooming mophead flowers that may be blue or pink.
- Hydrangea Nikko Blue – A very cold hardy hydrangea that will turn pink in alkalilne soil. It has a mophead.
- Hydrangea Purple Tiers – Lacecap type with double flowers. The flowers are deep purple when the soil is acid and pink when it is alkaline.
- Hydrangea Emile Mouillere – This vigorous variety is one of the most popular whites. It will rebloom in the right conditions and has a mophead
- Hydrangea Glowing Embers – a pink mophead that blooms from summer through fall
Color Changing Hydrangeas
Have you had a hydrangea plant which started out with one color flower and changed to something totally different? This is not unusual. I planted a big leaf hydrangea and it was filled with blue blossoms the first year. This year, the blooms are about 3 times the size and the color is pink!
Many hydrangea blossom will change color depending on the soil pH. Acidic soils with a pH of less than 5.5 will result in blue flowers; soils with a pH greater than 5.5 produce pink flowers.
White flowers on hydrangeas are not affected by soil pH so they do not change and are always white.
How to change hydrangea colors yourself
It is possible to change the color of hydrangeas yourself although this can take many months.
To increase acidity (for deeper-blue flowers): Apply a solution of 1⁄4 ounce aluminum sulfate per gallon of water three times per year.
Hydrangea pests and diseases
Hydrangeas are relatively trouble free, but are sometimes affect by aphids, powdery mildew, Japanese beetles and spider mites.
Disease include brown spots, brown leaves and fading colors of flowers (usually the latter means too much sun.)
Two types of fungal diseases affect hydrangeas:
- cercospora leaf spot (begins as brown or purple spots on the leaves near the base of the plant)
- anthracnose (produces large brown spots on the leaves that turn lighter brown or tan in the center)
Natural remedies for fungus on hydrangeas include using compost tea, hydrogen peroxide or garlic oil. Also remove the diseased leaves from the plant as soon as you see them. This will help to prevent the diseases from spreading further to more of the plant.
Rust is another common problem. This fungal disease looks like round, orangey spots on the underside of hydrangea leaves. Using soaker hoses rather than sprinklers or spray nozzles can help.
Drying Hydrangea Flowers
The large blossoms of hydrangea plants are very easy to dry indoors. Drying hydrangea flowers will bring the outdoors into your home for use in dried flower arrangements.
There are several ways to do this. You can let the flowers dry on the plant, or dry them indoors by hanging them upside down. The blooms can be dried using borax to preserve them (Which will keep their color), or mixing glycerin with water. As the stems drink up the water, the blooms will dry and turn color.
For tips on how to water dry hydrangea flowers, see this post.
If you would like a reminder of this post later, pin this image to one of your Pinterest gardening boards, so that you can easily find the tips for drying, propagating and growing hydrangeas when you need them.
Now it’s time to hear from you. What is your favorite type of hydrangea to grow? Have you tried taking cuttings from the plant to root? I’d love to hear your comments below.
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