How to Grow and Care for Hydrangeas

Sai Nursery offers a diverse selection of hydrangeas with expert care advice. Our varieties, including bigleaf and climbing hydrangeas, thrive with proper watering, partial shade, and well-draining soil. Visit us for quality plants and personalized tips to ensure your garden flourishes beautifully.

Hydrangea, a genus of erect or climbing woody shrubs in the family Hydrangeaceae, is native to the Western Hemisphere and eastern Asia, with about 23 known species. Several species are cultivated in greenhouses and gardens for their showy, often ball-like flower clusters. The French hydrangea, or hortensia (Hydrangea macrophylla), is widely cultivated in many varieties for its large globular flower clusters in colors of rose, lavender, blue, and occasionally white. These florist’s hydrangeas are often forced for holiday use. The flower color varies depending on the acidity of the growing medium: rose-pink under neutral to low soil acidity and blue under stronger acidity, with blue flowers produced by adding chemicals to increase acidity early in the growing process. Another notable species is the Hills-of-snow, or wild hydrangea (Hydrangea arborescens), a shrub slightly more than 1 meter (4 feet) tall with rounded clusters of white flowers.Hydrangeas are well-suited to the climate in Sydney, where they thrive due to the moderate temperatures and ample rainfall. Here's a brief guide to growing hydrangeas in Sydney:

Growing Conditions:

Sunlight: Hydrangeas in Sydney benefit from morning sun and afternoon shade. They do best in dappled sunlight or partial shade to protect them from the intense midday sun.

Soil: They prefer well-drained soil that is rich in organic matter. Slightly acidic to neutral soil is ideal.

Watering: Consistent moisture is crucial, especially during the hotter months. Ensure the soil remains moist but not waterlogged.

Planting :

Timing: The best time to plant hydrangeas in Sydney is during the cooler months, either in early spring or autumn.

Location: Choose a location with partial shade and good air circulation to prevent fungal diseases.

Care and Maintenance:

Watering: Regular watering is important, particularly during dry spells. Mulching around the base of the plant helps retain moisture.

Fertilization: Fertilize hydrangeas in early spring and again in late summer with a balanced, slow-release fertilizer.

Pruning: Prune dead, diseased, or damaged wood in late winter or early spring. For Hydrangea macrophylla, avoid heavy pruning as they bloom on old wood.

Flower Color Adjustment: To change flower colors, adjust the soil pH. For blue flowers, the soil should be more acidic (add aluminum sulfate), and for pink flowers, the soil should be more alkaline (add lime).

 

 

Condition Requirement:

Water and Hardiness:

Bigleaf hydrangea thrives in cool, moist environments with relatively small seasonal and day-night temperature variations. The ideal temperature range for growth is 18-29 °C, and winter temperatures should not drop below -1 °C. For flower bud differentiation, the plant requires temperatures of 4-7 °C for 6-8 weeks. Blooming is encouraged at temperatures around 19 °C, while flowers tend to fade more quickly at temperatures above 30 °C. Bigleaf hydrangea has specific soil requirements; the soil should be moist, well-drained, and free from water accumulation. Climbing hydrangea thrives in its native woodland habitats, where it benefits from the consistent moisture of a humid environment. This species prefers evenly moist soil and demonstrates moderate drought tolerance once established. To maintain optimal hydration levels, watering should adhere to a weekly schedule. Climbing hydrangea is best suited for outdoor cultivation due to its climbing habit, making it ideal for garden walls or trellises where rainfall can naturally supplement irrigation needs.

 

Sunlight Requirements for Climbing Hydrangea :

Preferred Sunlight:

• Partial Sun: Ideally, climbing hydrangea should receive about 3-6 hours of sunlight daily. This replicates its native environment under sparse forest canopies.
• Full Sun to Full Shade Tolerance: Although climbing hydrangea can tolerate more than 6 hours of sunlight, it prefers diffused light to prevent leaf scorching. It can also grow in full shade, but this may slow down its growth rate.

Optimal Placement:

• Morning Sunlight: The best outdoor location is where it can get full morning sun while being shaded during the hotter afternoon hours.
• Adjusting for Climate: In colder climates, climbing hydrangea may require more sunlight (at least 6 hours a day). In warmer climates, about 3 hours of sunlight is sufficient.

Indoor Sunlight Essentials

Artificial Lighting:

• When Natural Light is Insufficient: Use artificial lights to supplement natural sunlight, especially in winter or less sunny indoor spaces.
• LED Lights: These are effective for indoor plant lighting and can be customized to provide specific wavelengths.
• Wattage and Placement:
  • Full Sun Plants: 30-50W/sq ft
  • Partial Sun Plants: 20-30W/sq ft
  • Full Shade Plants: 10-20W/sq ft
  • Place light sources 12-36 inches above the plant.
• Duration: Mimic natural daylight hours, generally 8-12 hours per day.

Outdoor Sunlight Essentials

• Versatility: Climbing hydrangea can handle variable sunlight conditions, from full shade to full sun.
• Excessive Light: Though tolerable, too much light can cause leaf scorching.
• Seasonal Adaptation: The plant adapts well to seasonal changes in light availability.

Signs of Light Issues

Insufficient Light:

• Small Leaves: New leaves may be smaller than usual.
• Leggy Growth: Stems may become elongated and sparse.
• Faster Leaf Drop: Older leaves may drop prematurely.
• Slower Growth: Overall growth may halt or slow down.
• Lighter-Colored Leaves: New leaves may appear pale or have irregular color patterns.

Excessive Light:

• Chlorosis: Leaves turn yellow due to chlorophyll breakdown.
• Sunscald: Leaves or stems show pale, bleached, or necrotic areas.
• Leaf Curling: Leaves curl or twist to reduce sunlight exposure.
• Wilting: Leaves and stems droop due to increased water loss.
• Leaf Scorching: Leaves develop brown, dry, and crispy edges or patches.

Solutions for Light Issues

Indoor Solutions for Insufficient Light:

• Gradual Adaptation: Move plants to sunnier spots gradually until they receive 3-6 hours of sunlight daily.
• Use Artificial Lights: Provide additional light with desk or ceiling lamps, or invest in professional grow lights.

Outdoor Solutions for Insufficient Light:

• Reduce Obstructions: Prune trees or branches blocking sunlight.
• Transplanting: Move smaller plants during the dormant period to a sunnier location.

Indoor Solutions for Excessive Light:

• Optimal Placement: Move plants to an east-facing window for gentler morning sunlight.
• Pruning: Trim off dehydrated or withered parts.

Outdoor Solutions for Excessive Light:

• Shade Nets: Use shade nets during hot weather to filter sunlight.
• Watering: Ensure plants are well-watered, especially in the morning and evening.
• Check Light Requirements: If necessary, transplant to a shadier location.
• Pruning: Remove any completely dehydrated or withered parts.

By following these guidelines, you can ensure your climbing hydrangea receives the appropriate amount of light, promoting healthy growth and vibrant blooms.

Temperature Range for hydrangea :

Climbing hydrangea prefers cool and moist environments with relatively small seasonal and day-night temperature variations. The optimal temperature range for growth is between 18 to 29°C, and winter temperatures should not drop below -1°C. For flower bud differentiation, temperatures of 4 to 7°C for 6-8 weeks are required. Blooming can be promoted at around 19°C, while temperatures above 30°C can cause the flowers to fade faster. Climbing hydrangea has strict soil requirements, favoring moist, permeable soil that is free of accumulated water.

 Best Soil for hydrangea:

Climbing hydrangea requires soil that is rich in humus and well-drained. It thrives in moist soil but is not resistant to waterlogging. To improve drainage and permeability in heavy soil, adding coarse sand or organic fertilizer is recommended, which also boosts the organic matter content. For soil that dries out easily, covering it with organic mulch helps retain moisture while ensuring proper ventilation.

The soil pH affects the flower colors of some varieties of bigleaf hydrangea. In acidic, aluminum-rich soils, they bloom in blue, while in alkaline soils, they bloom in pink. To control flower color, you can adjust the soil pH by adding aluminum sulfate for acidity or lime for alkalinity.

Care Guide for Bigleaf Hydrangea:

Planting

• Ideal Planting Time: Early spring or late autumn is best for planting bigleaf hydrangea. Transplanting after the plant has gone completely dormant ensures a very high survival rate.
• Alternative Planting Times: Late spring and early summer are also suitable, but it's crucial to maintain moist and well-draining soil during this period.
• Initial Care: During the initial stage of transplanting, provide proper shading to reduce evaporation and prevent sunburn. This helps the plant establish itself more effectively.

 

Watering Guide for Hydrangea:

Big leaf Hydrangea

• Water Demand: Bigleaf hydrangea requires a very large amount of water.
• Watering Frequency: At least three times a week.
• Seasonal Adjustments: Increase watering frequency in dry areas or during hot summers. Adjust based on the season to ensure soil remains moist but not waterlogged.
• Signs of Watering Needs: Quickly supplement water if the leaves begin to wither.

Climbing Hydrangea

• Native Habitat: Thrives in woodland environments with consistent moisture.
• Soil Preference: Prefers evenly moist soil and demonstrates moderate drought tolerance once established.
• Watering Schedule: Water weekly to maintain optimal hydration levels.
• Ideal Placement: Best suited for outdoor cultivation, ideal for garden walls or trellises where rainfall can naturally supplement irrigation needs.

Fertilizer :

Big leaf hydrangea requires a substantial amount of water, with a recommended watering frequency of at least three times a week. In dry areas or during hot summers, this frequency should be increased. The soil should always remain moist but free from standing water, and adjustments to the watering schedule should be made seasonally based on these criteria. If the leaves of the bigleaf hydrangea begin to wither, it's crucial to supplement water immediately. On the other hand, climbing hydrangea thrives in its native woodland habitats, benefiting from the consistent moisture of a humid environment. This species prefers evenly moist soil and shows moderate drought tolerance once established. Watering should follow a weekly schedule to maintain optimal hydration levels. Climbing hydrangea is best suited for outdoor cultivation due to its climbing habit, making it ideal for garden walls or trellises, where natural rainfall can help supplement irrigation needs.

 

Common Problems with Bigleaf Hydrangea

Why Are the Leaves Withering?

Bigleaf hydrangea often displays leaf withering during hot summers. While it enjoys sunlight, it cannot tolerate intense sunlight, especially in the summer. Its large leaves contribute to rapid water loss, and exposure to daylight after significant water loss can cause the leaves to wither.

Preventive Measures:

• Location: Select a planting location with filtered light and partial shade to protect the plant from intense sunlight.
• Soil: Use a loose, air-permeable, and well-draining soil medium to ensure proper hydration and avoid waterlogging.
• Watering: Maintain consistent watering to keep the soil moist but not waterlogged, adjusting the frequency based on weather conditions and plant needs.