Hydrangeas – Variety to Delight
Pruning, Drying, Changing Color & Winter Care
Hydrangeas are divas — beautiful, but they like things just right. Here’s how to keep them happy.
Hardly any other flower has seen such a rise in recent years as the hydrangea. In bridal bouquets, on Instagram, in every other garden — hydrangeas are everywhere. And rightly so: when they bloom, it’s a spectacle. But hydrangea care does have a few quirks you should know about.
What you’ll find here: when and how to prune hydrangeas, how to change hydrangea color, how to dry them, and how to keep a hydrangea bouquet fresh in the vase for as long as possible.
Hydrangea at a glance
Botanical: Hydrangea
Origin: Japan, China, North America
Species: approx. 80 species, hundreds of varieties
Most popular: bigleaf hydrangea (H. macrophylla)
Blooming season: June – September
Cut flower: June – October
Vase life: 7 – 14 days
Difficulty: medium
Where do hydrangeas come from?
Most hydrangea species come from East Asia — Japan and China. In Japan, they have been revered for centuries. The name “Hydrangea” comes from Greek and means “water vessel” — a reference to how thirsty this plant is.
In the 18th century, plant collectors brought the first specimens to Europe. In Austria, they have been popular since the 19th century — both in the garden and as cut hydrangea flowers at the florist.
Meaning of hydrangeas
The meaning of hydrangeas varies depending on the culture. In Japan: gratitude and sincere feelings. In Europe: grace, abundance, sometimes vanity.
- Blue hydrangeas: loyalty, constancy
- Pink hydrangeas: romance, warmth
- White hydrangeas: purity, elegance — perfect for weddings
- Purple hydrangeas: understanding, spirituality
For bridal bouquets with hydrangeas, white and soft pink varieties are used. They give the bouquet volume and a romantic fullness that hardly any other flower can offer.
Changing hydrangea color — how does it turn blue?
The most common question: “How do I make my hydrangea blue?” The answer is chemistry — the soil pH.
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Blue
Acidic soil (pH 4.5–5.5) + aluminum
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Pink
Neutral to alkaline soil (pH 6+)
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White
Always stays white — cannot be changed
Add alum (potassium aluminum sulfate) to the watering water — 5 g per liter, every 2 weeks from March to June. At the same time, mulch with rhododendron soil. This only works for pink varieties — white hydrangeas always stay white.
Pruning hydrangeas — when and how?
When pruning hydrangeas, most people make the biggest mistake of all: they prune at the wrong time.
Important: Mophead hydrangeas and lacecap hydrangeas form their flower buds the previous year. If you cut them back drastically in spring, you cut off the blooms! Only remove frozen and dead shoots.
Panicle hydrangeas (H. paniculata) and smooth hydrangeas (H. arborescens) bloom on new wood — these can be cut back hard in spring.
Drying hydrangeas — three methods
Dried hydrangeas last for months as decoration. The three best methods for drying hydrangeas:
1. Water evaporation method (recommended): Place hydrangeas in a vase with 3–5 cm of water and let it slowly evaporate without refilling. The blooms dry gradually and keep their shape.
2. Hang upside down: Tie the stems together and hang them upside down in a dry, dark place. Leave for 2–3 weeks. Gives a slightly more rustic look.
3. Glycerin preservation: 1 part glycerin, 2 parts hot water. Place the stems in the mixture and leave for 2 weeks. The blooms stay supple.
Best time: late August to September, when the blooms start to feel slightly papery. If cut too early, they will wilt as they dry.
Hydrangeas in a vase — care tips
Hydrangeas in a vase are more demanding than other cut flowers — their thick, woody stems do not absorb water well.
How to make hydrangeas last:
- Cut the stems at an angle and peel away 3–4 cm of bark at the bottom end
- Also cut a cross into the end of the stem
- Use plenty of fresh, lukewarm water with flower food
- Mist the flower heads regularly with water
- Keep in a cool spot, out of direct sunlight
If a hydrangea starts to droop: recut the stem and fully submerge the entire flower head in cold water for 30 minutes. It often recovers completely.
Winter care for hydrangeas
Most garden hydrangeas are winter hardy, but the flower buds are sensitive:
- In November, cover the root area with leaves or brushwood
- Mophead hydrangeas: protect shoots with fleece (this is where the buds are)
- Potted hydrangeas: place against the house wall, wrap the pot with bubble wrap
- Water occasionally in winter too, when the weather is frost-free
Fertilize hydrangeas
Hydrangeas are heavy feeders. Fertilize hydrangeas with hydrangea fertilizer or rhododendron fertilizer. Twice: in April and June. Do not fertilize after August.
Bouquet with hydrangeas
A hydrangea bouquet makes a statement. A single hydrangea can fill a vase. Especially popular: hydrangea flower bouquet combined with roses, baby's breath, or eucalyptus. For bridal bouquets with hydrangeas, we recommend white or soft pink varieties.
Hydrangeas at MoBlumen Vienna
Fresh hydrangeas in season — single stems or in a bouquet. Also with expert advice for wedding floristry.
Frequently asked questions about hydrangeas
Add alum to the watering water (5 g/liter) every 2 weeks from March to June. Keep the soil acidic with rhododendron soil. This only works for pink varieties, not white ones.
Mophead hydrangeas: only remove frost-damaged shoots in spring. Panicle hydrangeas and smooth hydrangeas: cut back to 2–3 pairs of buds in spring.
The woody stems do not absorb water well. Solution: peel back the bark at the end of the stem, cut a cross into it, and submerge the entire flower in cold water — 30 minutes is often enough to revive it.
Fresh flowers at MoBlumen Vienna
Hydrangeas, roses, bouquets, and more — hand-tied and delivered fast.
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Also read: Flowers for Allergy Sufferers - Guide