Many beginners may feel intimidated by the showy hydrangea. Fortunately, we're here to help you grow hydrangeas and to help you feel confident in your ability to care for these beautiful heirloom flowers!
There are many varieties that differ in size and flower color. You can even grow pink or purple flowers depending on the pH of the soil, and each has unique requirements.
Most people do not realize that hydrangeas have been in the wilds of Japan and Indonesia for millions of years. Some hydrangea fossils are almost 60 million years old! The Japanese were the first to cultivate the hydrangea, with the plant mentioned in poems dating back to 710 AD.
The hydrangea flowers are said to represent love, understanding, and gratitude, which can motivate many to plant hydrangeas in their garden. Let's dive into this in-depth guide to learn all about growing hydrangeas in your own garden!
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Brief instructions for care
If you know how to grow hydrangeas, you'll enjoy perennial blooms. Source: Timothy Valentine
|Common names||Hydrangea, hydrangea|
|Scientific name||Hydrangea spp.|
|Height & Spread||Up to 15 feet tall and 6-10 feet wide|
|Bright||Partly sun to shade|
|floor||Well-drained and moist soil|
|water||Deep watering in hot weather|
|Pests & Diseases||Aphids, Japanese beetles, spider mites, root rot, powdery mildew, bacterial leaf spot|
Everything about hydrangeas
Hydrangea macrophylla. Source: Mauro Halpern
There are around 70 species of hydrangeas in Asia and it wasn't until the 18th century that hydrangeas were planted in England. The botanical name of the hydrangea is Hydrangea spp., Known simply as hydrangea or hydrangea. Each species will have a common name, like French hydrangeas and Oakleaf hydrangeas.
Hydrangeas are deciduous perennials when they are not exposed to extreme temperatures. Hydrangeas are evergreen in the Mediterranean. Hydrangeas are dicotyledonous leaves with simple leaves that have serrated edges and reticulate veins. The attributes vary depending on the type of hydrangea, but the flowers are at the heart of hydrangea plants.
The flower cluster ranges in color from white and lime green to pink and blue. Each star-shaped flower has four to five petals. Blooming flowers produce a sweet fragrance that is pleasant and distinctive. Hydrangeas make great ornamental plants and can attract pollinators such as bees and butterflies to the garden.
The most common hydrangeas are shrubs, but there are also climbing plants and trees so you can find one that will fit your landscape. Mature size varies by species, but some can grow up to 15 feet tall and 10 feet wide. You can also find a strain that will thrive in containers to add beauty to your outdoor space.
Types of hydrangeas
Hydrangea arborescens, variety "Pink Annabelle". Source: byb64
While there are many types and varieties of hydrangeas, we'll limit ourselves to a few of the most popular hydrangeas. H. arborescens, H. paniculata, H. quercifolia, H. macrophylla, and H. serrata are the five that we will highlight in this section.
H. arborescens ‘Smooth hydrangea’
The smooth hydrangea is native to the eastern United States and has a white flower color that blooms from early summer through fall. The stem bark is textured and peeling, and is usually wider than it is tall, reaching three to five feet in height. Compared to its cousin, the hydrangea macrophylla, the leaves are thinner and rougher. It prefers partial shade and a lot of moisture.
H. paniculata ‘Panicle hydrangea’
Also known as Peegee hydrangeas, they are one of the easiest to grow because they love the sun and are resistant to the cold. The flower color of H. paniculata ranges from lime green to white to pink with elongated racemes. Panicle hydrangeas bloom in early summer and reach heights of up to two meters.
H. quercifolia & # 39; Oakleaf Hydrangea & # 39;
The Oakleaf hydrangea is also native to the eastern United States. It gets its name from the oak leaf shape of its leaves, which turn purple or red in autumn. The immature flower is white and turns purple with age. These plants need a sheltered location in the garden for the winter months so that they do not die. Optimal conditions ensure that she grows up to 4-6 feet tall with healthy flowers and a flowering period in early summer.
H. macrophylla ‘Bigleaf hydrangea
Of the many types of hydrangea, this one is one of the most popular because of the hydrangea flowers it produces. A common variety is Endless Summer, as the flowering time extends into early autumn. The large mophead flowers come in a wide variety of flower colors. To make it a blue hydrangea, you need acidic soil. More susceptible to the cold than other varieties, with a preference for shade to partial sun, it grows three to six feet tall.
H. serrata ‘Mountain hydrangea’
Similar to the bigleaf hydrangea and requiring the same hydrangea care, it has smaller leaves and flowers. It will reach heights of 2-4 feet. The flower color can be blue or pink with a flowering time in midsummer. To get a blue hydrangea, plant it in acidic soil, and for the pink hydrangea flowers, plant it in alkaline soil.
Hydrangea quercifolia, the oak leaf hydrangea. Source: intheburg
Once you've learned the basics, hydrangeas aren't difficult to care for. You will find that growing hydrangeas is fun and worthwhile. This next section describes what to do when planting hydrangeas in your garden.
Light & temperature
Plant hydrangeas in partial shade in a protected spot. Typically where they can get warmth from the morning sun and protection from full sun in the afternoon shade. You can use full sun if it's not too hot; Some varieties are more heat tolerant. USDA growth zones 5-7 are best for these ornamentals.
They grow best in temperatures between 50 and 60 degrees Fahrenheit. Unless you are growing a hardy variety, consider protecting your plants from the cold. To do this, cover the roots with a thick layer of mulch and plant them in a sheltered place. To protect them from strong winds, cover them with a wire cage wrapped in a burlap sack or plastic bag.
Water & moisture
Hydrangeas prefer even moisture and need to be watered at least three times a week until the roots are formed. Once established, water at the rate of 1 inch per week to keep the soil moist. Watering the base of the plant in the morning will keep the leaves from withering in the hot sun and prevent fungus from growing. Soaking hoses or drip irrigation can help with watering.
Overwatering can cause root rot, stunted growth, and yellowing of the leaves. They can tolerate humid climates if they are protected from the scorching sun. To prepare your hydrangea for winter, water it deeply before it freezes. If the soil doesn't freeze, pour deeply and sufficiently to prevent it from drying out.
Fertile soil that is alkaline or acidic is ideal for optimal hydrangea care. If you have a clay or sand type of soil, remove some soil and add plenty of compost to allow the water to drain through the soil enough to prevent root rot while still holding enough to keep the plant happy. Otherwise, your plants will thrive on soil that is high in organic matter.
No specific soil pH is required to grow these plants. However, if you have a large-leaved hydrangea (H. macrophylla), you can change the flower color by adjusting the pH of your soil. Acid soil below 6.5 will color the flowers blue, while neutral to alkaline soil will produce pink flowers. Add lime to make alkaline soil or aluminum sulfate to get the blue hydrangeas.
For the healthiest plant, fertilize your hydrangea regularly. Use an all-purpose compost once a month during the growing season. Then add a slow release fertilizer during the winter months in late winter or early spring so that it has food to grow and flower buds and flowering time when it wakes up.
Repot your hydrangeas in early spring before they get upset. Examine the root ball for rot and carefully realign any roots surrounding the root ball. Use organic potting soil in your new pot that will allow good drainage to prevent water damage to the roots.
There are a few ways to propagate hydrangeas, one choice no better than the other. Let's look at a few so you can decide which method is right for you.
When sowing, you can either sow directly as soon as the danger of frost has passed, or you can start sowing indoors for 6-8 weeks before planting outdoors. Keep in mind that it can take up to two seasons for your new hydrangea to bloom. Some hydrangeas will also self-seed, but this is not an effective method of ensuring more hydrangeas.
Another option is to divide an existing hydrangea plant. Do this in the fall, just before your plant goes to sleep. Divide a plant with at least two stems, then use a shovel to separate the stem from the root. Fertilize and water your severed plant deeply.
The most popular method of propagation is to take a cutting from one or more hydrangea bushes. Choose a new branch with no flowers and make sure there are three to four pairs of leaves on the branch. Remove a pair of leaves and dust the root hormone on the leaf node. Next, put the branch in moistened potting soil and place it in a warm place with indirect sunlight.
Pruning hydrangeas is easy and the technique will depend on the variety of hydrangea you are growing. Pruning hydrangeas will help control their mature size and prepare them for the next growing season.
The large-leaved hydrangeas (H. macrophylla), Oakleaf and Mountain (H. serrata) should be cut back after the flowers have faded in late summer, as the flowers bloom on old growth, also known as old wood. That way, you can better see which is the old wood and which is newer growth. The pruning of these varieties is only used to remove dead or diseased wood. Do not prune in the fall, winter, or spring to prevent accidental removal of flower buds.
Flowers that bloom on new growth (also known as new wood), such as smooth hydrangea (H. arborescens) and panicle hydrangea (H. paniculata), are pruned back in late winter before new growth begins. Prune these varieties all the way to the ground if you want larger flowers for the next season. For sturdier stems with smaller flowers, cut the stems to a height of 18 to 24 inches.
Deadhead spent a flowering season during the growing season, taking care not to cut any new buds. Stop dying by late summer as the old flowers that remain through the winter can protect new buds from the wind and cold.
Hydrangea serrata. Source: UBCgarden
Fortunately, hydrangeas don't have many pests and diseases, but there are a few worth mentioning that affect the health of this ornamental plant. Caring for hydrangeas involves learning about common problems.
The most common problem is have no flowers on your hydrangea. Pruning new wood instead of old wood (which removes flower buds), inadequate winter protection, and poor sun exposure and nutrients are common factors to consider if your plant is not blooming.
Aphids are small green (sometimes black) insects that are more likely to interfere with new growth because it is easier for them to pierce the stem and leaves to extract the sap. They secrete a substance called honeydew that attracts ants. If the aphids continue to feed on your hydrangea, the leaves will curl and wither. The best way to get rid of aphids is to blast them with water. If that doesn't work, neem oil or insecticidal soap are effective treatments. Consider a pyrethrin spray if the infestation is extremely severe.
Japanese beetles arrive in the middle of summer and can devastate hydrangea plants within a few days. They often feed on the Oakleaf hydrangeas. Fortunately, they don't kill the plant, but it will look unsightly when done. Japanese beetles are easy to spot because they are metallic green and have brownish / copper colored wings with small white tufts under the wing covers. Hand-pick the beetles and place them in a bucket of soapy water or sprinkle them with neem oil. Adding milky spores or beneficial nematodes to the soil can prevent their return.
Spider mites feed on the plant cells and cause yellow spots on the leaves and deformed stems. Since spider mites are tiny, you'll know they're there when you see webs on your hydrangeas. It's best to try the least invasive method first, so spraying off with water may be enough. Ladybugs are a natural enemy of spider mites, as well as aphids, so these beneficial insects can be purchased or otherwise brought into your garden. Neem oil is effective on these too.
Root rot often occurs in plants stressed by drought and affects oak hydrangea (H. quercifolia) more than other varieties. This fungal infection causes the leaves to turn yellow or brown, the plants wither, and / or the root ball and stem turn brown. The best treatment is prevention. Don't water your hydrangeas and plant them in well-drained soil. If they are already infected, you may be able to use an organic copper fungicide if the disease has not progressed.
Powdery mildew is another fungal disease that can affect the hydrangea. It can be seen more on the bigleaf hydrangea (H. macrophylla). Signs are white powder on the leaves or yellow and purple leaf spots. If you catch it early enough, you can remove the affected leaves and make sure there is enough airflow between the plants to prevent it from spreading. Otherwise, natural neem oil can be effective.
Bacterial leaf spot is caused by a bacterial infection that causes purple or red spots to form on the leaves. It can often be seen on smooth-leaved hydrangeas (H. arborescens). It usually starts at the base of the plant and works its way up. Remove affected leaves as soon as possible to prevent this infection from spreading. If the disease is severe, remove the affected hydrangea. Copper-based fungicides are sometimes recommended but are not 100% effective.
frequently asked Questions
Hydrangea paniculata, also called pannicular hydrangea. Source: wallygrom
Q: where is the best place to plant a hydrangea?
A: The best place to plant a hydrangea shrub is in a sheltered area, where it gets full morning sun and shade on those hot midsummer afternoons.
Q: Do hydrangeas grow back every year?
A: Hydrangeas are perennials (i.e. they grow back every year). However, if you plant a variety that is not hardy, it can die in the cold winter months.
Q: How long does it take for a hydrangea to reach full size?
A: Hydrangeas grow quickly in optimal conditions. Knowing the average mature size of your specific hydrangea shrub will give you a starting point. Plant hydrangeas in the best growing conditions as detailed in this guide and you can see your hydrangea grow up to two feet per year until it is mature.
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