Hydrangea
Hydrangea macrophylla
The only common garden plant whose flower color changes based on soil chemistry — anthocyanin pigments bind to aluminum in acidic soil to produce blue.
How to care for hydrangea
For blue flowers, acidify soil to pH 5.5 with aluminum sulfate; for pink, raise pH to 6.5+ with garden lime. Most macrophylla varieties bloom on old wood — prune only immediately after flowering, never in spring.
Garden uses & design ideas
Best garden use
Use it as structure near paths, fences, or foundation beds, leaving enough mature width so pruning stays light and natural.
Pair it with
Hostas, Astilbe, Ferns make easy companion choices because they share similar light, water, or visual texture needs.
Layout tip
Match it with part shade exposure, keep it in the same moist-bed zone as other thirsty plants, and check USDA zones 5-9 before planting. Use the garden planner to test spacing around its mature size: 3-6 ft tall and wide.
Gardener note — Double-check local invasive, edible, and toxicity guidance with your county extension office before planting around pets, children, or natural areas.
Companion plants
Hydrangea grows well alongside these — similar light, water, and texture needs.
Common pests & problems
Where it grows best
Native to Eastern Asia (Japan, Korea); thrives in USDA hardiness zones 5-9.
Frequently asked about hydrangea
What USDA zones does Hydrangea grow in?+
Hydrangea is hardy in USDA zones 5-9. Outside these zones, it can usually be grown indoors or as a seasonal annual.
How much sun does Hydrangea need?+
Hydrangea prefers part shade. Place it where it gets that light most of the day for best growth and flowering.
How often should I water Hydrangea?+
Hydrangea has high water needs. Water frequently — this plant prefers reliably moist soil. For blue flowers, acidify soil to pH 5.5 with aluminum sulfate; for pink, raise pH to 6.5+ with garden lime. Most macrophylla varieties bloom on old wood — prune only immediately after flowering, never in spring.
How big does Hydrangea get?+
Hydrangea reaches a mature size of 3-6 ft tall and wide. Growth rate is moderate, so plan spacing accordingly when planting.
What plants grow well with Hydrangea?+
Hydrangea pairs well with Hostas, Astilbe, Ferns, Boxwood, Heuchera. These companions share similar care requirements and don't compete aggressively for resources.
What pests affect Hydrangea?+
Common Hydrangea problems include aphids; spider mites; scale; powdery mildew. Catching early signs in routine inspection prevents most damage.
When does Hydrangea bloom?+
Hydrangea blooms in summer in blue, pink, white, or purple. Deadheading spent flowers (where applicable) often encourages a longer bloom window.
Design a garden with hydrangea in minutes
Drag plants into a 3D space, walk through it, or upload a photo and let AI redesign it. Test spacing around its mature size before you plant.
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