Hydrangea macrophylla (Thunb.) Ser.
Hydrangea macrophylla, commonly known as Bigleaf hydrangea, French hydrangea, or mophead hydrangea, is a flowering plant species belonging to the family Hydrangeaceae. The plant is native to Japan, Korea, and China, but it is now widely cultivated worldwide as an ornamental plant for its beautiful and showy flowers.
General Appearance
Hydrangea macrophylla is a deciduous shrub that can grow up to 2 meters in height with a similar spread. The plant features large, dark green leaves that are broadly elliptic or ovate in shape with serrated edges. The leaves measure around 7–20 cm long and 5–15 cm broad and are arranged in pairs opposite each other on the stem. The plant bears large and beautiful flowers that are typically pink, blue, or white in color.
Common Names
The plant is commonly known by various names, including Bigleaf hydrangea, French hydrangea, mophead hydrangea, hortensia, penny mac, and lacecap hydrangea. These names reflect the varied colors, shapes, and sizes of the plant's flowers.
Uses
Hydrangea macrophylla is mainly grown as an ornamental plant in gardens, parks, and landscapes. The plant's showy flowers and lush foliage make it an ideal choice for adding color and texture to any garden. The plant is also valued for its ability to grow in shady areas, making it a perfect plant for landscaping in areas with limited sunlight.
However, the plant also has medicinal uses. The leaves and roots of the plant have been used in traditional Chinese medicine to treat various ailments, including inflammation, pain, and urinary tract infections. The plant is believed to have diuretic, antipyretic, and anti-inflammatory properties.
As it grows best in a rich, moist, and well-drained soil, Bigleaf hydrangea requires regular maintenance and pruning to keep it healthy and beautiful. Overall, this plant is a beautiful addition to any garden, with both ornamental and medicinal benefits.
Light Requirements
Hydrangea macrophylla requires either partial shade or full shade depending on the climate. In excessively hot and dry regions, it should be grown in partial shade. Whereas, in areas with milder climates, it grows splendidly in full shade. Direct sunlight can cause the leaves to burn and flowers to wilt prematurely, so it should be avoided.
Temperature Requirements
Hydrangea macrophylla prefers moderate temperatures and is sensitive to both excessive heat and frost. It thrives best in USDA Hardiness Zones 5 to 9 and grows the most in temperatures ranging from 60°F to 70°F (15.5°C to 21.1°C). High temperatures can result in wilting and yellowing of the leaves, while cold temperatures can cause damage to the roots and the flowers.
Soil Requirements
The soil in which Hydrangea macrophylla is planted plays a crucial role in its overall growth and development. The plant thrives best in well-draining soil that is rich in organic matter. The ideal soil pH level for this plant is between 5.5 to 6.5. Hydrangea macrophylla grows best in loamy soil that retains moisture and drains well. It requires a regular supply of water, but not to the point where the soil becomes waterlogged as the roots can become prone to rotting.
Cultivation Methods
Hydrangea macrophylla (Thunb.) Ser. is a versatile flowering plant that can thrive in a range of conditions, from full sun to part shade. It is hardy in zones 6-9 and prefers moist, well-drained soil. When planting, dig a hole twice the width of the pot and mix in organic matter to improve soil quality. Space the plants 3-4 feet apart to allow for adequate air circulation.
Watering Needs
Hydrangea macrophylla requires consistent moisture to thrive. Water deeply once per week, or more frequently in hot, dry weather. Avoid getting water on the foliage, which can lead to fungal diseases. Mulching around the base of the plant can help retain moisture and regulate soil temperature.
Fertilization
Hydrangea macrophylla benefits from regular fertilization throughout the growing season. Apply a balanced fertilizer, such as a 10-10-10, every 4-6 weeks from spring until mid-summer. Avoid fertilizing in late summer or fall, as this can promote new growth that may not have time to harden off before winter.
Pruning
Pruning is an essential aspect of Hydrangea macrophylla care. To maintain a healthy and tidy plant, remove any dead, damaged, or diseased wood as soon as it appears. Supplemental pruning depends on the desired shape and size of the plant. For larger blooms, prune in late winter or early spring, cutting back old wood to a pair of healthy buds. For a more compact shape, trim lightly in summer after flowering.
Propagation of Hydrangea macrophylla
Hydrangea macrophylla (Thunb.) Ser., commonly known as bigleaf hydrangea, is a beautiful flowering plant that is often propagated to create more plants. There are different propagation methods that can be used to propagate Hydrangea macrophylla, and these include:
Propagation by Softwood Cuttings
Hydrangea macrophylla can be easily propagated through softwood cuttings. Softwood cuttings are taken in late spring or early summer when the stems are still green and have not yet become woody. The cuttings are usually about 4 to 6 inches long and should be taken from the tips of the stem.
The cuttings are then dipped in rooting hormone and placed in a pot filled with a well-draining potting mix. The pot should be covered with a clear plastic bag to create a humid environment, which will help the cuttings develop roots. The pot should be kept in a warm and bright location, but out of direct sunlight. After a few weeks, the cuttings should start to develop roots, and the plastic bag can be removed.
Propagation by Division
Hydrangea macrophylla can also be propagated by division. This method involves dividing an existing plant into several smaller plants, each with its own roots and stems. The best time to divide hydrangeas is in late winter or early spring when they are still dormant.
To divide a hydrangea, start by digging up the plant carefully, making sure not to damage the roots. Once the plant is out of the ground, use a sharp spade or knife to carefully divide the plant into smaller sections, each with its own roots and stems. The smaller sections can then be replanted in new locations, and they should start to grow and develop new foliage in a few weeks.
Propagation by Seeds
Hydrangea macrophylla can also be propagated by seeds, but this method is not commonly used as it can be slow and unpredictable. However, if you do want to propagate Hydrangea macrophylla by seeds, start by collecting the seeds from a healthy and mature hydrangea plant in the fall.
The seeds should be sown in a pot filled with a well-draining potting mix and covered lightly with soil. The pot should be covered with a clear plastic bag to create a humid environment, which will help the seeds germinate. The pot should be kept in a warm and bright location, but out of direct sunlight.
It's important to note that plants grown from seeds may not have the same characteristics as the parent plant, and it can take several years for them to mature and produce flowers.
Common Diseases and Pests Affecting Hydrangea macrophylla
The Hydrangea macrophylla, also known as bigleaf hydrangea or French hydrangea, is a popular flowering shrub in many gardens and landscapes. However, like many plants, it is vulnerable to different diseases and pests that may attack it. Knowing some of the common ones and how to manage them is key to keeping this plant healthy and thriving.
Diseases
Bacterial wilt: This is a disease caused by the bacteria Pseudomonas solanacearum that can rapidly kill the plant. Symptoms include wilting, yellowing, and browning of leaves, usually starting from the lower part of the plant. Management strategies include planting disease-free plants, avoiding overwatering, and removing and destroying infected plants.
Leaf spot: This disease is caused by the fungal pathogen Cercospora hydrangeae and appears as small, brownish spots with yellow halos on the leaves. Severe infections can lead to defoliation and overall plant decline. Management involves removing infected leaves, improving air circulation, and avoiding overhead watering to reduce humidity.
Powdery mildew: This is a fungal disease causing white, powdery patches on the leaves and stems. Infected plants can have distorted growth, reduced flowering, and premature leaf drop. Management involves improving air circulation, avoiding overhead watering, and applying fungicides as needed.
Pests
Aphids: These are tiny insects that suck sap from the plant, causing stunted growth, distorted leaves, and honeydew excretion that attracts ants. Management involves controlling ant populations, using insecticidal soap or oils, and introducing natural predators like ladybugs.
Spider mites: These are very tiny pests that feed on the sap, turning the leaves yellow and causing them to drop. Management includes removing infested leaves, avoiding over-fertilizing, and applying miticides or insecticidal soaps.
Japanese beetle: This pest feeds on the leaves, flowers, and buds, causing skeletonization of leaves and reduced flowering. Management techniques include handpicking, using pheromone traps, and applying insecticides.
With good horticultural practices and these disease and pest management strategies, you can enjoy the beautiful flowers of your Hydrangea macrophylla for years to come.
