When to plant
Plant in spring or fall. Most hydrangeas are perennial in zones 3–9 (varies by species). Bloom time varies: bigleaf types (H. macrophylla) bloom in summer on old wood — protect from winter dieback. PeeGee and Annabelle types bloom on new wood — easier to grow in cold climates. Prune at the right time for your variety to avoid cutting off next year's blooms.
Soil & site
Rich, well-drained soil with high organic matter. pH 5.5–6.5 produces blue flowers in bigleaf hydrangeas; pH 6.5–7.0 produces pink flowers. Neutral to slightly alkaline soil turns flowers pink or red; acidic soil turns them blue. Add aluminum sulfate to acidify, garden lime to raise pH. Work in generous amounts of compost.
Feeding
Apply a balanced slow-release fertilizer in spring when new growth begins. A second feeding in midsummer encourages continued bloom. Avoid fertilizing in late summer or fall — this stimulates tender new growth that frost can damage. High-phosphorus fertilizers can reduce aluminum uptake and shift blue flowers toward pink.
Common problems
Powdery mildew in humid, crowded conditions (improve air circulation). Cercospora leaf spot (brown leaf spots — avoid overhead watering). Scale insects. Iron chlorosis in alkaline soils (yellowing leaves with green veins). Flower buds killed by late spring frost (site in a protected location). Deer browse foliage heavily.
When to harvest
For fresh cut flowers: harvest when blooms are about three-quarters open. For dried arrangements: harvest when the blooms are fully open and the petals feel slightly papery to the touch — this is the point at which they will dry most successfully without shrivelling too much. For seeds: collect seed heads in late fall when completely dry and brown.
How to harvest
Cut stems at a 45-degree angle in the early morning, removing at least 12 inches of stem. Strip all leaves below the waterline immediately. For drying: cut fully opened blooms on a dry day, remove all leaves, and hang upside down in a warm, dark, airy room for 2–3 weeks. Alternatively, place stems in an inch or two of water and let them dry slowly in place — many hydrangeas dry beautifully this way.
Storage & use
Fresh cuts last 5–7 days in a vase — condition in cold water for several hours after cutting. Dried hydrangeas keep 1–2 years if stored away from direct sunlight (sun bleaches the color quickly). Protect from humidity in storage. Some varieties hold their color better than others when dried — Annabelle (white), Limelight (green-white), and Incrediball are excellent dryers.
Useful for growing hydrangea
A few things that make this one easier — chosen for this plant, not a generic list.
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