Smooth Hydrangea Hydrangea arborescens 'Grandiflora'
ABOUT
Hydrangea arborescens 'Grandiflora', commonly known as 'Hills of Snow' hydrangea, is a perennial shrub well-admired for its distinctive floral display. This cultivar produces large, showy flower heads that can give the appearance of snowy mounds – hence the name. The blooms are composed of numerous small, tightly packed flowers, and they emerge in a pristine white hue which may gently age to a pale green as the season progresses. These impressive flower heads sit atop sturdy, upright stems and create a visually stunning contrast with the plant's broad, deep green leaves. The leaves themselves have a slightly toothed edge and a velvety texture, and they are typically heart-shaped. This variety of hydrangea is deciduous, meaning that it sheds its leaves in the fall. In addition to its flowers and foliage, 'Hills of Snow' hydrangea may occasionally produce small capsule-like fruit that contributes little to the ornamental qualities of the plant. The robust blooms and lush vegetation combine to give the plant a classic, rounded, and dense overall appearance that is particularly popular in ornamental gardens.
About this plant
NamesFamily
Hydrangeaceae
Synonyms
Smooth Hydrangea, Wild Hydrangea, Sevenbark, Hills Of Snow, Snowball Hydrangea, Annabelle
Common names
Hydrangea arborescens var. grandiflora.
ToxicityTo humans
Smooth hydrangea contains compounds that may release cyanide when ingested. While poisoning in humans is rare and typically occurs only if large amounts are consumed, it can lead to symptoms such as nausea, vomiting, diarrhea, and stomach pain. In severe cases, cyanide toxicity could lead to more serious symptoms, including dizziness, a rapid pulse, respiratory problems, lethargy, and seizures. Always exercise caution and refrain from eating any part of this plant.
To pets
Smooth hydrangea is also toxic to pets due to the same compounds that are harmful to humans. If pets consume parts of this plant, they might exhibit symptoms like vomiting, diarrhea, depression, and sometimes more intense reactions such as cyanide poisoning which can lead to difficulties in breathing, increased heart rate, and even seizures. It is important to prevent your pets from ingesting any part of the smooth hydrangea due to its potential toxicity.
CharacteristicsLife cycle
Perennials
Foliage type
Deciduous
Color of leaves
Green
Flower color
White
Height
4 feet (1.22 meters)
Spread
6 feet (1.83 meters)
Plant type
Shrub
Hardiness zones
3
Native area
Eastern United States
Benefits
General Benefits- Aesthetic Appeal: Hydrangea arborescens 'Grandiflora', commonly known as Smooth Hydrangea, is valued for its large, showy flower heads that enhance the visual appeal of gardens.
- Versatility: It can be grown in a variety of soil types and is tolerant to different levels of sunlight, making it suitable for many garden settings.
- Wildlife Attraction: The flowers attract pollinators such as bees and butterflies, contributing to the biodiversity of the garden ecosystem.
- Seasonal Interest: Smooth Hydrangea provides interest throughout the seasons with its flowers in summer and fall, and peeling bark in the winter.
- Erosion Control: The extensive root system of Hydrangea arborescens 'Grandiflora' can help stabilize soil and prevent erosion in sloped areas.
- Low Maintenance: Once established, this plant requires minimal care, needing only occasional pruning to maintain shape and size.
- Durability: It is a hardy plant that can withstand colder climates, making it appropriate for many temperate regions.
- Cultural Significance: Hydrangeas are often used in floral arrangements and have cultural importance in various societies, adding to their desirability for planting.
Medical Properties- Traditional Diuretic: Often used by Native Americans to promote kidney and bladder health.
- Root and Rhizome Uses: Historically for treating kidney stones and other urinary conditions.
- Anti-lithic Property: Believed to aid in preventing and dissolving calculi or stone formation.
- Gravel Root: The common name for a variety derived from its use in urinary gravel (small stones).
Air-purifying QualitiesThis plant is not specifically known for air purifying qualities.
Other Uses- Pressing Flowers: The blossoms of the Annabelle Hydrangea can be pressed and used in crafting to create bookmarks, cards, or framed botanical art.
- Landscape Lighting: The large, white blooms of Annabelle Hydrangeas reflect garden lights well, making them a good choice for planting around outdoor lighting features for night-time aesthetics.
- Erosion Control: Annabelle Hydrangea can be used on slopes or banks to help prevent soil erosion, thanks to its relatively extensive root system.
- Fabric Dye: The flowers, when dried, can be used to create a natural dye for fabrics, giving them a soft, antique hue.
- Holiday Decorations: Dried Annabelle Hydrangea flowers can be sprayed with festive colors and used for Christmas or other holiday decorations.
- Cut Flower Arrangements: Due to their voluminous and robust flower heads, they are widely used in cut flower arrangements for events and home décor.
- Backdrop for Photography: The lush flowers and foliage make a picturesque backdrop for garden photography and weddings.
- Garden Borders: When planted in a row, these plants create an attractive and thick hedge border for gardens and walkways.
- Support for Climbing Plants: The strong woody stems of mature Annabelle Hydrangeas can provide support for lightweight climbing plants.
- Artistic Inspiration: The unique shape and size of the blooms can serve as inspiration for artists and designers working in various media.
Interesting Facts
Feng ShuiThe smooth hydrangea is not used in Feng Shui practice.
Zodiac Sign CompitabilityThe smooth hydrangea is not used in astrology practice.
Plant Symbolism- Heartfelt Emotions: The lush, rounded blooms of the hydrangea represent the fullness of emotion, often used to express genuine, deep feelings.
- Gratitude and Apology: Due to their bountiful appearance, hydrangeas can symbolize both thankfulness and remorse, making them appropriate for apologies or expressions of gratitude.
- Understanding: The hydrangea's intricate patterns of smaller flowers within larger blooms are sometimes taken as a symbol of comprehensive understanding or enlightenment.
- Abundance and Prosperity: As the hydrangea can produce many flowers and has a lavish look, it can also represent abundance or prosperity in one's life.
WaterSmooth hydrangeas need consistent moisture, especially in the first few years and during the height of summer. It is essential to water these shrubs deeply, aiming for the root zone rather than just wetting the foliage. Water about once a week, providing roughly 1 inch of water each time. However, always adjust your watering frequency based on rainfall, as too much water can lead to root rot. During hot and dry spells, you may need to water twice a week, and less frequently during cooler, wetter periods. On average, this translates to around 0.5 to 0.75 gallons per week, ensuring the soil remains moist but not waterlogged.
LightSmooth hydrangeas grow best in partial shade, though they can tolerate full sun if they are kept moist. The ideal spot offers morning sunlight and afternoon shade, protecting the plant from the intense midday heat. They can also thrive in dappled sunlight under the canopy of open trees, which naturally replicates their native woodland habitats. Avoid deep shade, as it can reduce the robustness of the blooms.
TemperatureSmooth hydrangeas thrive in a range of temperatures, with ideal growth occurring between 65°F and 75°F. They are hardy in USDA zones 3 through 9, tolerating minimum winter temperatures down to -40°F and maximum summer temperatures up to around 95°F. It is important to protect these shrubs from late spring frosts that can damage new growth, as well as from extremely high temperatures which can stress the plant.
PruningPruning smooth hydrangeas is done to encourage robust blooms and maintain a tidy plant shape. They bloom on new wood, so the best time to prune is late winter or early spring before new growth begins. Removing old blooms and about one third of the oldest stems each year will promote healthier and larger flower heads. Dead, damaged, or crossing branches should be pruned to improve air circulation and overall plant health. Prune annually for best results.
CleaningAs needed
SoilSmooth hydrangea prefers rich, moist, well-draining soil with a pH between 5.5 and 6.5. A good mix consists of peat, compost, and regular garden soil to ensure adequate nutrition and drainage. Monitoring the soil pH is essential as it affects bloom color and overall health.
RepottingSmooth hydrangea, typically grown as a garden shrub, does not require frequent repotting. If grown in containers, repotting every 2-3 years or when root-bound is sufficient to maintain its health and vigor.
Humidity & MistingSmooth hydrangea thrives in environments with average humidity levels. While adaptable, it does well with morning dew and some additional atmospheric moisture, reflecting its natural woodland habitat.
Suitable locationsIndoor
Provide bright light, keep soil moist, and ensure high humidity.
Outdoor
Plant in partial shade, ensure moist, well-drained soil.
Hardiness zone
3-9 USDA.
Life cycleThe life of the Hydrangea arborescens 'Grandiflora', commonly known as the smooth hydrangea, begins with seed germination, which occurs with the right balance of moisture and temperature. Following germination, the plant enters the seedling stage, developing roots and the first shoots that push through the soil surface. It then transitions into the vegetative stage where rapid growth of foliage takes place, and the plant establishes a sturdy root system and stem structure. The hydrangea reaches maturity and enters the flowering stage, typically in early to mid-summer, presenting large, white, showy flower heads that attract pollinators. After pollination, seeds develop, and once mature, they disperse, completing the reproductive cycle. At the end of the growing season, the plant goes into dormancy, shedding leaves and conserving energy to survive the winter, to then regrow and restart the cycle in the spring.
PropogationPropogation time
Summer
Hydrangea arborescens 'Grandiflora', commonly known as the smooth hydrangea, is most effectively propagated through stem cuttings. This method is usually done in late spring to early summer when the plant is actively growing and the stems are new and pliable. To propagate, a cutting approximately 6 inches (around 15 centimeters) long is taken from a healthy branch, ensuring at least three sets of leaves are present. The lower sets of leaves are removed, and the cut end is dipped in rooting hormone to encourage root development. The cutting is then planted in a moist potting mix, ideally in a container that will allow for sufficient drainage. Keeping the cutting in a warm, well-lit environment, but out of direct sunlight, watered consistently until roots have established often yields a well-rooted plant in a few weeks.
