Bigleaf hydrangea (Hydrangea macrophylla 'Pia')
Dwarf pink mophead Bigleaf hydrangea, Hydrangea macrophylla 'Pia', offers 2-3 ft mounds, perfect for borders. Requires medium water and thrives in part shade.
Complete Plant Information
Overview
Hydrangea macrophylla ‘Pia’ is a valued deciduous shrub, specifically a dwarf mophead cultivar of the popular Bigleaf hydrangea. It offers gardeners a manageable size, typically forming a neat mound reaching 2 feet tall and wide, ideal for smaller garden spaces where its showy summer blooms create significant impact. This specific variety is prized for its reliable pink summer coloration, which contrasts beautifully against its dark green foliage.
As a member of the Hydrangea macrophylla group, ‘Pia’ benefits from rich soil and consistent moisture, making it a robust addition to shaded borders and foundation plantings. While it provides excellent long-season interest, understanding its cultural needs, especially concerning winter protection in colder zones, will ensure the best flowering performance each subsequent year.
The classic appeal of the Bigleaf hydrangea lies in its substantial, globose flower clusters that appear mid-summer. Hydrangea macrophylla ‘Pia’ brings this beauty in a compact form, offering a medium-maintenance shrub that rewards proper care with reliable summer color, enhancing patio areas or shaded woodland gardens.
Fast Facts
- Plant Family: Hydrangeaceae
- Plant Type: Deciduous shrub
- Hardiness Zones: USDA Zones 5-9
- Size at Maturity:
- Height: 2-3 ft
- Spread: 2-3 ft
- Bloom Time: July to August
- Bloom Description: Pink
- Sun Exposure: Part shade
- Water Needs: Medium
- Maintenance Level: Medium
How to Grow
Hydrangea macrophylla ‘Pia’ performs best when planted in rich, well-drained soil that maintains medium moisture levels. Aim for a location receiving part shade; while it can tolerate full sun, this requires diligent attention to keeping the soil consistently moist throughout the growing season to prevent wilting and scorch. Soil pH treatments, which influence color in many Bigleaf hydrangeas, are less critical for ‘Pia’ as it is selected for pink blooms, though you may adjust pH in late autumn or early spring if aiming for subtle shifts.
Watering should be regular, especially during establishment and dry spells, given its medium water needs. Mulching is highly recommended; apply a 3-inch layer of shredded bark, compost, or peat around the base annually to help stabilize soil temperature and conserve moisture. Pruning is minimal for this shrub. If pruning is necessary, perform it immediately after flowering concludes by cutting back the flowering stems only to a strong, healthy set of buds.
Winter care is crucial, particularly in USDA Zone 5. While generally hardy to Zone 6, plants in Zone 5 benefit from sheltered siting. In harsh winters, flower buds may be lost or stems may die back to the ground. If die-back occurs, prune stems back in late winter or early spring before new growth begins. Be aware that even with protection, weather inconsistencies can sometimes cause poor flowering results in volatile years.
Landscape Uses
The compact stature of Hydrangea macrophylla ‘Pia’, reaching only 2 to 3 feet tall and wide, makes it exceptionally versatile in landscape design. It excels when used for grouping or mass planting within a shrub border, creating a substantial block of color. Its neat, rounded habit also qualifies it as an excellent specimen or accent shrub near homes, patios, or walkways where its summer mophead blooms can be easily admired.
For structured settings, consider using Hydrangea macrophylla ‘Pia’ as a low, informal hedge along property lines or screening low utility boxes. Due to its adaptability to containers, it serves wonderfully as a focal point on decks or balconies, provided containers are large enough to support its moisture demands and are insulated during harsh winters to protect the root ball.
Pair this Bigleaf hydrangea with plants that share similar cultural needs, such as hostas, astilbes, or other shade-loving perennials. Its dense form provides an excellent mid-ground layer beneath taller flowering trees or broadleaf evergreens, showcasing the signature blooms of the Hydrangea macrophylla series.
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 or mophead form (globose flower clusters of mostly showy sterile florets). ‘Pia’ is a dwarf mophead cultivar that typically grows in a mound to 2’ tall by 2’ wide and features pink flowers.
Tolerances
Potential Problems
Bigleaf hydrangeas, including Hydrangea macrophylla ‘Pia’, face a few potential issues requiring gardener vigilance. Susceptibility exists for bud blight, bacterial wilt, leaf spot, and mildew, often exacerbated by overly humid conditions or poor air circulation. Managing these foliar diseases involves ensuring proper spacing between shrubs and watering at the base rather than overhead.
Aphids are occasional visitors to the new growth, especially in the spring. If an infestation becomes noticeable, treatment with insecticidal soap or simply blasting them off with a strong stream of water is usually sufficient. Avoid heavy nitrogen fertilization late in the season, as this encourages soft, tender new growth that is more vulnerable to pests and winter damage.
The most unpredictable problem for the Bigleaf hydrangea is winter injury in zones near the minimum hardiness threshold. Low temperatures, sudden freezes, or icy conditions can damage or kill flower buds, leading to fewer or no blooms, regardless of the protective measures you take.
Frequently Asked Questions
What hardiness zones is Bigleaf hydrangea suitable for?
Hydrangea macrophylla ‘Pia’ is hardy in USDA Zones 5 through 9. Gardeners in Zone 5 should take extra measures to protect stems from harsh winter die-back.
How large does Hydrangea macrophylla ‘Pia’ grow?
This specific cultivar is valued as a dwarf mophead, typically growing into a mound 2 to 3 feet tall and spreading 2 to 3 feet wide.
What sun exposure does Bigleaf hydrangea need?
It thrives best in part shade. To maintain good health and bloom quality, avoid intense afternoon sun unless you can guarantee consistently moist soil throughout the day.
When does Hydrangea macrophylla ‘Pia’ bloom?
This Bigleaf hydrangea produces its showy pink flowers during the peak summer months, typically blooming from July through August.
Conclusion
Hydrangea macrophylla ‘Pia’ stands out due to its reliable, compact form and the classic beauty of its summer mophead blooms, making it an indispensable choice for smaller, shaded garden spots. Ensuring consistent moisture and providing protection in colder zones helps maximize the vibrant pink display of this Bigleaf hydrangea. Before planting, confirm your location falls within USDA Zones 5-9 and plan your site preparation during the cooler shoulder seasons for the best results.
Companion Planting
When positioning Hydrangea macrophylla ‘Pia’, focus on companions that appreciate similar part shade and rich, moist soil conditions. Hostas provide excellent textural contrast with their broad leaves, thriving beneath the higher canopy of the shrub. Similarly, woodland perennials like Astilbe or Bleeding Heart (Dicentra spectabilis) enjoy the filtered light offered by the Bigleaf hydrangea and share its need for consistent moisture.
Avoid planting water-hungry companions too close, as competition for deep soil hydration can stress the hydrangea, particularly during summer heat waves. For groundcover around the base, consider using shade-tolerant, shallow-rooted plants like Vinca minor or Pachysandra terminalis, which will complement the dwarf size of Hydrangea macrophylla ‘Pia’ without disrupting its feeding zone.
Seasonal Care Calendar
Spring is the ideal time to prune out any weak or winter-damaged stems from the previous year on your Hydrangea macrophylla ‘Pia’, done just as new buds begin to swell. Apply fresh mulch in early spring to help conserve water as temperatures rise. Summer requires monitoring moisture levels; deep, infrequent watering is better than frequent shallow sprinkles.
In the late autumn or very early spring, consider implementing any established soil pH adjustments if flower color is a primary concern for next season, remembering that ‘Pia’ naturally trends toward pink. Avoid heavy fertilization near the end of summer to allow the plant to properly harden off its wood growth before winter dormancy sets in.
