Bigleaf Hydrangea Hydrangea macrophylla 'Altona' (H)

Water

Bigleaf hydrangeas, including the 'Altona' variety, should be watered deeply enough to moisten the soil around the roots, typically requiring about 1 gallon of water per plant. The watering frequency depends on the weather and soil moisture levels, but on average, providing water once or twice a week during active growth periods is sufficient. In hot and dry conditions, increased watering may be necessary, while in cooler or rainy periods, less frequent watering is needed. Ensure the soil is well-draining to prevent waterlogging. Monitor the top inch of soil for dryness as an indicator for when to water next.

Light

Bigleaf hydrangeas such as 'Altona' prefer bright, indirect sunlight or partial shade. They thrive best in a location where they can receive morning sunlight and afternoon shade to avoid the intense heat of the day. An east-facing spot that gets sun in the morning and protection from the harsh afternoon rays is ideal for these plants.

Temperature

Bigleaf hydrangeas like 'Altona' are best suited to temperatures between 65 to 75 degrees Fahrenheit during the day and not below 50 degrees Fahrenheit at night. They can typically withstand a minimum temperature of around 20 degrees Fahrenheit, but frost or prolonged exposure to temperatures below freezing can damage the plant. Ideal growing conditions ensure that temperatures remain within the specified range for most of the year.

Pruning

Pruning bigleaf hydrangeas like 'Altona' is done to remove dead wood and encourage bushier growth. Prune right after the blooms fade in late summer but before new buds form, usually by mid-August. Do not prune in spring, as you may remove the current year's flowers. Remove only dead and spent flowers, leaving live stems as these will bear the next season's blossoms.

Cleaning

As needed

Soil

The best soil mix for Bigleaf Hydrangea (H) should be rich, porous, and well-draining with an addition of organic matter, such as compost or peat moss, to retain moisture. The soil pH should be around 5.5 to 6.5 for optimal growth, however, acidic soil with pH below 6 will encourage blue flowers, while more alkaline soil above 7 will lead to pink flowers.

Repotting

Bigleaf Hydrangea (H) should be repotted when it becomes root-bound or the soil is exhausted, typically every 2-3 years. It's crucial to choose a slightly larger pot each time to allow for root growth.

Humidity & Misting

Bigleaf Hydrangea (H) thrives best with high humidity, around 50-60%. To maintain optimal humidity levels, consider placing a humidifier nearby or grouping it with other plants to create a microclimate with higher moisture in the air.

Suitable locations

• Indoor

  Place near bright window, keep soil moist.

• Outdoor

  Plant in morning sun, well-drained soil.

• Hardiness zone

  6-9 USDA

Life cycle

The life of the Bigleaf Hydrangea (Hydrangea macrophylla 'Altona') begins with germination, where the seed, given proper conditions of moisture and temperature, sprouts and develops roots and shoots. The seedling phase follows, characterized by slow growth as the young plant establishes a root system and initial leaves. Vegetative growth continues as the plant matures, developing a robust structure of stems and leaves, with the foliage often displaying a broad, serrated edge characteristic to the species. Flowering occurs typically in early summer, with the 'Altona' cultivar producing large, showy blooms that may change color based on soil pH, ranging from blue to pink. After pollination, if it occurs, the plant produces small capsules containing seeds, although many cultivars propagate more reliably via cuttings. The plant then enters a period of dormancy during colder months, with reduced growth and energy conservation, before re-emerging in the spring to repeat the cycle.

Propogation

• Propogation time

  Spring-Early Summer

• The most popular method of propagation for the Hydrangea macrophylla 'Altona', commonly known as the Bigleaf Hydrangea, is through softwood cuttings. This process is typically done in late spring to early summer when new growth is still tender. To propagate, a healthy stem with several sets of leaves is chosen. The cutting, about 5 to 6 inches (approximately 12.7 to 15.2 cm) long, is made just below a leaf node. Leaves near the bottom of the cutting are removed to reveal a section of stem, which is then dipped into a rooting hormone. The prepared cutting is placed into a pot filled with a well-draining soil mixture, ensuring the node where the leaves were removed is buried in the soil. The pot is placed in a warm, bright area out of direct sunlight, and the soil is kept consistently moist until roots begin to grow, which can take several weeks.