The ‘Lanarth White’ Hydrangea is a popular choice for gardens, known for its elegant appearance and pure white flowers. This beautiful shrub provides abundant blooms throughout the summer, adding a classic touch to any landscape.
Meet the Lanarth White Hydrangea
‘Lanarth White’ is a cultivar of Hydrangea macrophylla (bigleaf hydrangea). It features unique lacecap flowers: flattened clusters of large, sterile white sepals surrounding tiny, fertile florets that can be mauve-pink or blue. Unlike many other Hydrangea macrophylla varieties, its white blooms remain consistently white regardless of soil pH. This deciduous shrub typically grows to 1 to 1.5 meters (3 to 5 feet) in height and spread, forming a rounded, bushy habit with broadly ovate, green leaves.
Ideal Growing Conditions
For ‘Lanarth White’ Hydrangea to thrive, specific environmental conditions are required. Partial shade is ideal, especially in hotter climates, as intense afternoon sun can cause wilting or scorching. Morning sun is beneficial, followed by afternoon shade to protect the plant from harsh heat. While it tolerates full sun, consistent soil moisture becomes critical.
The soil should be rich, well-drained, and consistently moist, with ample organic matter. ‘Lanarth White’ prefers soil with a pH from slightly acidic to neutral. While these hydrangeas require substantial water, prevent waterlogging. Consistent watering is essential, particularly during dry or hot periods, often needing water two to three times per week.
‘Lanarth White’ is winter hardy in USDA Zones 6 through 9. In colder regions, such as USDA Zone 5, provide additional winter protection to safeguard flower buds from extreme cold and sudden temperature fluctuations. Applying a thick layer of mulch around the root zone can help insulate the plant.
Essential Care and Pruning
Fertilization can be done with a balanced slow-release fertilizer, such as a 10-10-10 or 12-4-8 NPK formula, applied in early spring. A second, smaller application might be beneficial in mid-summer, but avoid fertilizing late in the growing season, as this can encourage tender new growth vulnerable to winter damage. Water the plant thoroughly before and after applying granular fertilizer.
Understanding its blooming habit is crucial: ‘Lanarth White’ flowers on old wood, meaning flower buds for the next season form on stems from the previous year’s growth. Therefore, prune immediately after the plant finishes flowering in late summer. This timing allows sufficient time for new growth to mature and produce buds for the following year’s blooms. When pruning, remove any dead, weak, or crossing stems to maintain plant health and shape. Faded flower heads can be left on the plant through winter, as they offer some protection for dormant buds.
Troubleshooting Common Issues
A common concern is a lack of blooms. This can often be attributed to improper pruning, especially if stems bearing next year’s flower buds are removed at the wrong time. Late spring frosts can also damage tender new growth and developing flower buds, hindering blooming. Ensuring the plant receives adequate light, particularly morning sun, is also important for flower production.
Wilting, another common issue, indicates a watering imbalance. Underwatering, especially during hot and dry periods, causes the plant to droop as it struggles to take up enough moisture. Conversely, overwatering can lead to root rot, which also impairs the plant’s ability to absorb water, resulting in wilting. Yellowing leaves can signal several problems, including chlorosis, often due to nutrient deficiencies or excessive soil moisture. Maintaining consistently moist, well-drained soil and ensuring proper fertilization can help prevent these issues.
Beyond the Basics: Uses and Safety
‘Lanarth White’ Hydrangea is a versatile plant for various garden designs. It serves well as a specimen plant, in mixed borders, or for mass plantings. Its compact size also makes it suitable for container gardening on patios or balconies. The lacecap flowers attract pollinators.
All parts of the hydrangea plant contain cyanogenic glycosides and are toxic if ingested by humans or pets (dogs, cats, horses). Ingestion can cause mild stomach upset, vomiting, diarrhea, and lethargy. Contact with foliage may also cause skin irritation.