Hydrangea aspera ‘Hot Chocolate’ is a deciduous shrub known for its distinctive foliage and unique floral displays. Its striking appearance and ease of care make it a desirable plant for many garden settings.
Unique Characteristics of ‘Hot Chocolate’
‘Hot Chocolate’ is distinguished by its unique foliage. New leaves emerge deep chocolate or dark burgundy, maturing to a darker green with a rich undertone. The undersides often retain a deeper reddish-purple or burgundy, providing a striking backdrop for its flowers and differentiating it from other hydrangeas.
This plant grows into a rounded, bushy form, reaching 2 to 4 meters (6.5 to 13 feet) tall and spreading 1.5 to 2.5 meters (5 to 8 feet) over 10 to 20 years if unpruned. Its leaves are lance-shaped to narrowly ovate with a velvety, slightly hairy texture. From mid-summer to early autumn, ‘Hot Chocolate’ produces large, flattened lacecap flower clusters up to 30 cm (12 inches) across. These blooms feature tiny, violet-blue fertile florets surrounded by larger, cup-shaped soft pink or lilac sterile ray florets. The contrast between the dark foliage and the lighter blooms creates a visually appealing display. In autumn, the foliage displays warm reddish-bronze, amber, or golden tints before leaf drop.
Optimal Growing Conditions
Light Requirements
‘Hot Chocolate’ thrives in partial shade, particularly benefiting from morning sun followed by afternoon shade. While it can tolerate full sun in cooler climates, intense, direct afternoon sun can scorch its leaves and affect flower development. Insufficient light may lead to less vibrant foliage color.
Soil Preferences
This hydrangea prefers moist, well-drained soil rich in organic matter. An ideal pH is slightly acidic to neutral (6.0-7.0). Unlike some hydrangeas, ‘Hot Chocolate’ flowers maintain consistent color regardless of soil acidity. Incorporating well-rotted manure or compost improves soil structure, fertility, and moisture retention. For heavy clay soils, adding organic material enhances drainage, while for sandy soils, it improves water-holding capacity.
Watering Needs
Consistent moisture is important for ‘Hot Chocolate’, especially during its establishment period and dry spells. Deep watering at least once a week is recommended, increasing frequency during hot, dry weather. Water at the plant’s base to ensure roots receive moisture and to avoid wetting foliage, which can encourage fungal issues. Mulch helps retain soil moisture and regulate temperature. While this hydrangea appreciates moisture, it does not tolerate waterlogged conditions, so well-draining soil is crucial.
Temperature and Climate
‘Hot Chocolate’ is a hardy shrub, suited for USDA Hardiness Zones 7-9, though some sources indicate hardiness to Zone 5 (-29°C). In colder climates, a heavy layer of mulch around the base provides winter protection. Shelter from cold, drying winds is also beneficial. In regions with very cold winters, container-grown plants may require additional protection or relocation to a sheltered area.
Fertilization
Feed ‘Hot Chocolate’ in early spring with a balanced, slow-release fertilizer to support healthy growth and bloom production. A second application in mid-summer can encourage further blooming. Avoid fertilizing after late July or early August, as late-season fertilization can promote new growth vulnerable to winter damage. An annual application of a granular or slow-release fertilizer formulated for woody plants is usually sufficient. Over-fertilization can lead to excessive foliage growth at the expense of flowers.
Planting and Landscape Use
The optimal times for planting ‘Hot Chocolate’ are fall or early spring. This allows the shrub time to establish a robust root system before summer heat. When preparing the planting hole, dig it twice as wide as the root ball, ensuring the plant sits at the same level or slightly higher than the surrounding soil. A slight mound can aid water drainage away from the crown.
This hydrangea’s striking foliage and flowers make it suitable as a specimen plant, in mixed borders, woodland gardens, or city and courtyard gardens. Allow for its mature size of 2 to 4 meters tall and 1.5 to 2.5 meters wide to ensure proper air circulation and prevent overcrowding. ‘Hot Chocolate’ can also be grown in large containers, providing flexibility for smaller spaces or patio displays, though container plants may require more frequent watering and feeding.
Pruning for Health and Shape
Pruning ‘Hot Chocolate’ is minimal, as it blooms on old wood. The best time to prune is immediately after flowering or in late winter to early spring, before new growth begins. Removing spent flower heads encourages new growth.
Focus pruning on removing dead, damaged, or crossing branches to maintain the plant’s health and structure. For overgrown plants, a significant reduction of stems can be done in mid-summer without significantly impacting the following year’s blooms. If a more compact size or specific shape is desired, cut branches back by about one-third to a healthy bud. Regular pruning also helps improve air circulation within the plant.
Addressing Common Challenges
‘Hot Chocolate’ is a robust plant, but can encounter issues. Common pests include aphids and spider mites, which feed on plant sap and can distort leaves. Capsid bugs and vine weevils can also be occasional pests. Regular inspection helps early detection, allowing for prompt intervention with insecticidal soap or neem oil if needed.
Hydrangeas can be susceptible to powdery mildew and leaf spot. Powdery mildew appears as white fungal growth on leaves, especially in humid or crowded conditions. Leaf spot presents as tan spots with reddish-brown borders. Ensuring good air circulation through proper spacing, avoiding overhead watering, and cleaning up fallen leaves can help prevent these fungal issues. Environmental stresses like leaf scorch can occur from too much intense, direct sun, leading to browning or crisping leaves. Providing adequate shade, especially during the hottest part of the day, helps mitigate this. Consistent watering prevents wilting, while yellowing leaves might indicate overwatering.