Bigleaf hydrangea (Hydrangea macrophylla 'Lanarth White')

Overview

The Hydrangea macrophylla ‘Lanarth White’, a prized cultivar of the Bigleaf hydrangea, brings reliable summer color to shaded garden spots. This specific variety is valued because its pure white sterile florets stand apart, remaining white regardless of minor fluctuations in soil pH, unlike many other colored mopheads and lacecaps. As a compact, deciduous shrub, it forms a neat, rounded shape perfect for smaller landscapes or foundation plantings.

Gardeners appreciate the extended bloom period of Hydrangea macrophylla ‘Lanarth White’, typically flowering from July through August with attractive, flat, lacecap flower clusters. While it is generally a medium-maintenance shrub, providing consistent moisture and appropriate part shade ensures healthy growth and prolific flowering well into summer.

This beautiful Bigleaf hydrangea adds essential texture and contrast to shaded borders, offering interest long after spring bloomers fade. Its glossy foliage and distinct flower form make Hydrangea macrophylla ‘Lanarth White’ an excellent specimen plant, enhancing any space that receives dappled sunlight.

Fast Facts

• Plant Family: Hydrangeaceae
• Plant Type: Deciduous shrub
• Hardiness Zones: USDA Zones 6-9
• Size at Maturity:
  • Height: 2-3 ft
  • Spread: 2-3 ft
• Bloom Time: July to August
• Bloom Description: White
• Sun Exposure: Part shade
• Water Needs: Medium
• Maintenance Level: Medium

How to Grow

Planting the Hydrangea macrophylla ‘Lanarth White’ is best achieved in spring after the danger of hard frost has passed, ensuring rich, well-drained soil enriched with organic matter. While it prefers part shade, this Bigleaf hydrangea can tolerate full sun if the soil remains consistently cool and moist throughout the growing season. Proper soil preparation is critical for long-term success.

Maintain medium water needs by providing consistent, deep watering, especially during dry spells; hydrangeas wilt quickly when moisture levels drop too low. These plants generally require little pruning. If removal of old growth is necessary, prune immediately after flowering by cutting faded stems back to a pair of healthy, outward-facing buds. Avoid excessive pruning, as this removes next year’s potential flower wood.

Mulching is highly recommended for all Hydrangea macrophylla cultivars to help regulate soil temperature and maintain consistent moisture necessary for the best performance of Hydrangea macrophylla ‘Lanarth White’. In colder reaches of Zone 6, providing winter protection ensures flower buds survive harsh freezes; use heavy mulch or consider temporary wraps for maximum protection against bud loss.

Landscape Uses

The sturdy, compact growth habit of this Bigleaf hydrangea makes Hydrangea macrophylla ‘Lanarth White’ exceptionally versatile. It excels when grouped or massed within a shrub border, providing an excellent mid-layer of foliage and summer bloom. Due to its moderate height of 2-3 feet, it works beautifully near building foundations or patios where a large, unruly shrub would overwhelm the space.

Consider using this white-flowering cultivar as a bright accent plant against dark green or variegated evergreens, which offer excellent contrast for the blooms during July and August. The clean white flowers of the lacecap form complement almost any color palette, pairing well with hostas, ferns, and Astilbes, all of which share similar moisture and light requirements. It also performs admirably as a formal or informal hedge or as a standout feature in a large container where its need for moisture can be easily managed.

Standout Features

Flower Qualities

• Showy

Noteworthy Characteristics

Hydrangea macrophylla, commonly called big leaf hydrangea, is a deciduous shrub with a rounded habit that, in the St. Louis area, typically grows 3-6’ tall and as wide unless damaged by harsh winters or pruned smaller. It generally features serrate, obovate to elliptic, dark green leaves (4-8” long) and large clusters of long-blooming summer flowers in either lacecap form (flattened flower clusters of small fertile florets with scattered showy sterile florets often forming a marginal ring) or mophead form (globose flower clusters of mostly showy sterile florets). ‘Lanarth White’ is part of the lacecap group and features flattened flower clusters (corymbs) consisting primarily of small, fertile florets, with a few scattered, showy, pure white sterile ones often forming a marginal ring. It is a compact, deciduous shrub with a rounded habit which typically grows to 2-3’ tall and blooms for up to two months starting in July.

Tolerances

• No data provided

Potential Problems

This Bigleaf hydrangea faces some common issues that gardeners should monitor for proactive management. Potential problems include susceptibility to bud blight, bacterial wilt, leaf spot, and mildew, which are often exacerbated by poor air circulation or overly wet conditions. Aphids are occasional visitors that can usually be controlled with a strong jet of water or insecticidal soap if infestations become heavy. Maintaining good garden hygiene, ensuring adequate spacing between plants, and avoiding overhead watering can minimize fungal diseases common to this group.

Frequently Asked Questions

What hardiness zones is Bigleaf hydrangea suitable for?

Hydrangea macrophylla ‘Lanarth White’ is reliably hardy in USDA Zones 6 through 9, though extra winter protection is recommended for Zone 6 plantings.

How large does Hydrangea macrophylla ‘Lanarth White’ grow?

This compact variety typically reaches a mature height between 2 and 3 feet tall, with a proportionate spread of 2 to 3 feet wide.

What sun exposure does this Bigleaf hydrangea need?

For best results, plant Hydrangea macrophylla ‘Lanarth White’ where it receives part shade, as intense afternoon sun can scorch the foliage unless moisture is perfectly maintained.

When does Hydrangea macrophylla ‘Lanarth White’ bloom?

This shrub produces its distinctive white lacecap flowers from July right through August, providing substantial summer color.

Companion Planting

When planning your shaded garden beds alongside Hydrangea macrophylla ‘Lanarth White’, select plants that thrive in similar medium moisture and part shade conditions. Hostas provide varied foliage texture and color underneath the structure of the hydrangea, creating a lush, woodland feel. Groundcovers like Vinca minor or Pachysandra work well by suppressing weeds and keeping the soil cool near the base of the shrub.

For complementary vertical elements, consider Japanese Forest Grass (Hakonechloa macra) or tall, shade-tolerant native ferns. These companions won’t compete aggressively for nutrients while offering visual interest when the Bigleaf hydrangea is not in bloom. Always ensure good air circulation around the hydrangeas, even when grouping moisture-loving species together.

Seasonal Care Calendar

Spring preparation is vital for encouraging robust flowering on your Hydrangea macrophylla ‘Lanarth White’. Prune out any obviously winter-damaged or crossing stems in early spring just as buds begin to swell; avoid heavy pruning until after the first initial flush ends. Apply a fresh layer of mulch (about 3 inches deep) in late spring after the soil has warmed slightly to lock in moisture retention.

Summer care is focused almost entirely on consistent hydration; never let the shrub completely dry out during periods of heat. If you are growing this Bigleaf hydrangea in a location that received afternoon sun, water deeply during the morning hours. As summer ends, reduce fertilization, allowing the plant to harden off naturally in preparation for its first winter.

Conclusion

The Hydrangea macrophylla ‘Lanarth White’ offers dependable, elegant white summer blooms in a manageable, compact size, making it an exceptional choice for shaded garden design. Its distinct lacecap form and reliable flowering ensure it remains a favorite among Bigleaf hydrangea enthusiasts. Before planting, confirm that your location falls within USDA Zones 6-9 and plan to amend your soil to ensure excellent drainage for this beautiful shrub.