Smooth Hydrangea Care: Learn About Wild Hydrangea Shrubs

Smooth Hydrangea Care: Learn About Wild Hydrangea Shrubs

By: Teo Spengler

Wild hydrangea shrubs are more often called smooth hydrangeas (Hydrangea arborescens). They are deciduous plants native to the southeastern United States, but can be cultivated in U.S. Department of Agriculture plant hardiness zones 3 through 9. The wild hydrangea plant flowers from June until the first frosts. Read on for information about growing smooth hydrangeas.

Wild Hydrangea Shrubs

This species of hydrangea forms a low mound of heart-shaped green leaves and sturdy stems that turn dark yellow in the fall. The plant foliage has a coarse texture, and grows to about 3 to 4 feet (0.9 m. to 1.2 m.) tall with an even wider spread by the time fall comes around.

The flowers are fertile and of a uniform height, slightly flattened and displayed atop sturdy stalks. When they open, they are slightly green. The color changes to creamy white as they mature and then to brown as they wilt. Don’t try to change the color by changing the acidity of the soil; this species of hydrangea does not alter the blossom shade according to soil pH.

Various cultivars are available in commerce offering different flower shapes and colors. For example, the “Annabelle” cultivar bears pure white blossoms, round like snowballs and 8 to 12 inches (20 cm. to 30 cm.) in diameter. Some newer cultivars produce pink flowers.

Growing Smooth Hydrangeas

Smooth hydrangea care starts by selecting an appropriate planting location. A wild hydrangea plant won’t perform well in full sun in a hot location. Choose a location that gets sun in the morning but has some shade during the heat of the afternoon.

When you are planting wild hydrangeas, find a spot with well-drained, moist, acidic soil. Work in a few inches of organic compost before planting to enrich the soil.

Smooth Hydrangea Care

Once you finish planting wild hydrangeas and after they are established, irrigate them occasionally if the weather is very dry. These wild hydrangea shrubs do not support extended drought without suffering.

If you need to rejuvenate a wild hydrangea plant, prune the shrub to 6 inches (15 cm.) in springtime. It blooms on new wood and should produce stems and new blossoms by summer.

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Read more about Hydrangeas

Growing Hydrangeas

The Spruce / Claire Cohen Bates

Hydrangeas have been popular garden plants for decades. Older varieties add sentimental charm and new hydrangea shrubs can bloom from mid-summer through fall. Hydrangea flowers now come in an even wider variety of colors, including bright blue, deep red, and pale green. These versatile shrubs will thrive in both sandy coastal soils and in shady woodland sites and almost everything in-between.

To ensure hydrangea shrubs have time to establish a healthy root system before blooming, it is best to plant them in the fall or early spring at the latest. Once planted, hydrangeas are rapid growers averaging 24 or more inches of growth per year.

Botanical Name Hydrangea spp. (including H. macrophylla, H. serrata, and others)
Common Names Hydrangea
Plant Type Shrub
Mature Size Up to 15 feet
Sun Exposure Full sun to partial shade
Soil Type Any
Soil pH Any
Bloom Time Mid-summer through fall
Flower Color White, blue, green, red, pink, purple
Hardiness Zones 5 to 9
Native Area Asia and the Americas

Watch Now: How to Grow and Care for Hydrangeas

Description of hydrangea flowers

In the wild hydrangeas flowers are presented by shrubs up to 9.8 ft in height, small trees and lianas, able to climb tree trunks up to a height of 98.4 ft. In addition, depending on the species, they can be either evergreen or deciduous, and in cold climate zones flower growers prefer to grow deciduous hydrangea. The leaves of hydrangea are usually large, opposite, oval with an acute tip, often with serrated margins and well-defined venation. Hydrangea blooms from spring to frost with large spherical inflorescences, corymbose or paniculate, consisting of flowers of two types: small fertile (fruiting) flowers that are usually in the middle of the inflorescence, and large sterile (infertile) flowers blooming around the edges. There are, however, species in which all flowers in the inflorescence are fertile. Most of the hydrangeas bloom with white flowers, but, for example, bigleaf hydrangea (or French hydrangea) blooms not only with white and cream flowers, but also with red, blue, lilac and pink flowers, and the color directly depends on the hydrogen index of the soil (pH level): hydrangeas with beige and cream flowers grow in neutral soil, hydrangea with lilac or pink flowers grow in alkaline soil, hydrangeas with blue flowers grows in acidic soil as the plant absorbs the aluminum contained in the soil. The hydrangea fruit is a subglobose capsule with small seeds. Sometimes hydrangea is confused with plants from the closely related Schizophragma genus, but one should know that the so-called climbing hydrangea does belong to schizophragma genus.

Smooth Hydrangea Care

Most hydrangea arborescens like slightly acidic soil that is nutrient rich. Make sure to plant these in an area that is well drained to prevent root rot. However, the soil does need to be moist. This type of hydrangea does not do well in extended periods without rain. So be sure to water frequently, especially mid-summer. These shrubs can handle full sun depending on the variety. However, most varieties prefer to have some relief from the sun mid to late afternoon. If the shrub is in full-sun, be sure to carefully watch the leaves for droopiness, which typically means it needs more water.

According to the Missouri Botanical Garden website, these plants have no serious insect or disease problems. Many species of hydrangea, including this one, are susceptible to bud blight, bacterial wilt, leaf spots, mold, rust and powdery mildew. Watch for aphids, mites, scale and nematodes.

Best Time To Plant Hydrangeas

Hydrangeas purchased from a garden center have been growing outdoors in a pot. They can be planted at any time of the year. However, to get good results, keep these considerations in mind:

Whenever possible, plant in early summer or fall. Don't plant in early spring when frosts are still possible. I've lost two leafed-out plants that were killed when a late frost hit them.

Don't plant a hydrangea during the hottest part of the summer unless it can't be helped.

After planting a hydrangea, DO NOT LEAVE IT ALONE. Too often we rush to get our shrubs planted before we leave on vacation. Be on hand to give it some TLC and to keep it well watered.

About Smooth Hydrangea

Smooth hydrangea is native to the southeastern United States, so it is right at home in the Southern states. This hydrangea can grow to 10 feet tall and wide. It has long-lasting blooms, and once it begins to flower in the heat of June, it continues on until the chill of the first frost sets in. It also brings fall foliage to the garden when its beautiful, oval, gray-green leaves turn gold in autumn.

The blooms of the smooth hydrangea are stunning additions to the garden, as most selections produce snowball-like white flowers. One of the South's favorites is Hydrangea arborescens ‘Annabelle,' which is small—it grows to only 4 feet—but has a showy flowering season and produces huge clusters of bright white flowers. Beyond the white blooms, some smooth hydrangeas produce blossoms in light blue and soft pink hues.

Diseases & Pests

Powdery Mildew affects bigleaf hydrangeas the most. It appears as a white powder looking fungus on the top of the leaves. Purple and yellow spots on the leaves may appear as well.

This disease is mostly aesthetically disruptive… but, being that this is often the main purpose of this plant… one can see how disruptive it can be. Root Rot can kill the entire hydrangea plant.

Visual signs include progressive wilting and little white fan-shaped mycelia mats just under the bark at the stem-base near the soil-line. Also, in fall season, after lots of rain, honey colored mushroom fungus appear in the soil above roots that have this.

Keeping your hydrangea in its proper habitat (correct soil, temperature, sun, moisture) are the best defense against this disease.

Blister rust, and virescence, and bacterial wilt are some diseases that can harm your hydrangea. Blister rust will be visible, in that it produces clusters of orange spores on the bottom side of its leaves.

Aphids are a pest (insect) that can grow to numbers that make it very uncomfortable for your hydrangeas. They appear on new growth, more commonly. They secrete a clear sticky sugar based liquid. This can cause a black mold to grow on it. The sugary substance may also attract ants. The aphids themselves may also cause yellowing of the leaves, or distortion.

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