How to Grow Hydrangea Penny Mac
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Hydrangea Penny Mac
Hydrangea macrophylla 'Penny Mac'
shrubPenny Mac is a compact bigleaf hydrangea cultivar known for its ability to bloom on both old and new wood, providing reliable flowering even after harsh winters or pruning. It produces large, showy mophead flowers that can shift from pink to blue depending on soil pH. This deciduous shrub reaches 3-4 feet tall and wide, making it ideal for smaller landscapes and containers.
When should you plant Hydrangea Penny Mac in your zone?
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Example Hydrangea Penny Mac timeline · Pittsburgh, PA (Zone 6b)
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Plant Hydrangea Penny Mac
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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Harvest Hydrangea Penny Mac
Late summer into fallBefore the first fall frost (≈ Nov 8)
Sample dates for Pittsburgh, PA. Sign up to get exact Hydrangea Penny Mac dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 5-9, with best performance in zones 6-8
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Get my Hydrangea Penny Mac timeline →Growth Stages
Spring Emergence
4-6 weeksNew shoots emerge from buds on previous year's wood and new canes; foliage is bright green and tender
Wait until danger of late frost passes before pruning; apply mulch to regulate soil temperature; avoid late-season nitrogen fertilizer that encourages tender new growth
Vegetative Growth
6-8 weeksRapid leaf and stem development; plant reaches full size; deep green foliage with prominent veining
Maintain consistent moisture; apply balanced or low-nitrogen fertilizer (10-10-10); prune lightly if needed for shape; monitor for pests
Bud Formation & Flowering
2-4 weeks for bud formation, 4-8 weeks for active bloomingLarge flower buds form at stem tips; flowers open in mid to late summer in pink, blue, or purple hues depending on soil pH and aluminum availability
Continue regular watering; feed with phosphorus-rich fertilizer to support blooms; remove faded flowers to encourage continued blooming; deadhead spent flowers but leave stems for winter interest if desired
Late Summer to Fall
8-12 weeksFlowers fade but retain ornamental papery texture; foliage may show fall color (burgundy or bronze tones); wood hardens and buds set for next year
Reduce watering slightly as temperatures cool; do not fertilize; leave faded flowers on plant to help harden wood for winter; apply mulch in late fall in colder zones
Winter Dormancy
12-16 weeksPlant goes dormant; leaves drop; stems show brown coloration; flower buds remain visible at branch tips
In zones 5-6, protect with burlap or mulch mound to protect flower buds from extreme cold; no watering needed unless soil is bone dry; prune only in late winter if needed
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Spray with horticultural oil in late winter before growth begins; prune out heavily infested branches; monitor regularly
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Increase humidity with misting; spray with water forcefully to dislodge; use insecticidal soap if severe; avoid over-fertilizing with nitrogen
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and
(Erysiphe cichoracearum)
Improve air circulation by pruning interior branches; avoid overhead watering; remove infected leaves; apply fungicide in severe cases; water at soil level only
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Hand-pick beetles in early morning; use Japanese beetle traps away from plant; avoid insecticides that harm beneficial insects; neem oil may help
Uses
Cut & Dried Flowers
HouseholdPenny Mac's large mophead flowers are excellent for fresh floral arrangements and dry beautifully for long-lasting dried arrangements. The flowers retain color and structure well when dried properly. [source]
Ornamental Landscaping
HouseholdThe compact size and reliable blooming habit make Penny Mac ideal for hedges, foundation plantings, container gardens, and mixed shrub borders. Its extended bloom time provides summer and fall color. [source]
Pollinator Support
WildlifeHydrangea flowers attract bees, butterflies, and other beneficial insects throughout the blooming season, supporting local pollinator populations in the garden. [source]
Floral Design & Crafts
CraftThe large, showy flowers are prized by florists and craft enthusiasts for wedding arrangements, wreaths, and other decorative projects. Their color-changing ability allows customization based on soil chemistry. [source]
Harvest Tips
Hydrangea Penny Mac is grown for ornamental flowers, not harvest. Cut flowers for arrangements once they have fully opened and hardened; early morning cutting preserves freshness. Cut stems at 45-degree angle above a set of buds. Flowers can be dried by hanging stems upside down in a warm, dry location for 2-3 weeks.
Fun Facts
- 🌱 Penny Mac's flower color is determined by soil pH and aluminum availability: acidic soils (pH below 6.0) with available aluminum produce blue flowers, while neutral to alkaline soils (pH above 7.0) produce pink flowers. You can shift colors by amending soil with aluminum sulfate or lime.
- 🌱 Unlike many bigleaf hydrangeas, Penny Mac is noted for its ability to bloom on both old and new wood, making it more reliably floriferous even in colder climates where winter damage might kill flower buds on wood-bloomers only.
- 🌱 Hydrangea flowers were historically used in traditional medicine in Asia, and the plant's name comes from Greek words 'hydro' (water) and 'angea' (vessel), referring to the plant's water-loving nature and cup-shaped seed pods.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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