Smooth Hydrangea 'Incrediball' (Incrediball Hydrangea) care

Light

In the wild smooth hydrangea 'incrediball' grows on the bright edge of a forest canopy, not in the canopy and not in the open. Indoors, that translates to within a metre of an unobstructed window, sheer curtain optional. Part sun to full sun; morning sun with afternoon shade is ideal. It takes more shade than panicle types, but too much shade weakens stems and reduces bloom. The fastest test: a hand held at the leaf casts a soft-edged shadow at noon — sharp shadow means too much sun, no shadow means too little light.

Watering

Aim for when the top 3-4 cm of soil is dry, often every 2-4 days in summer for smooth hydrangea 'incrediball', but treat that as a starting point rather than a rule. A south-facing summer windowsill will dry the pot twice as fast as a north-facing winter room. Lift the pot; if it feels noticeably lighter than it did wet, water it. Moisture-loving; keep the root zone consistently moist, watering deeply in heat. The large leaves wilt quickly when dry. Mulch well to conserve moisture.

Soil and pot

Smooth Hydrangea 'Incrediball' grows best in rich, moist, well-drained soil. Fertile, humus-rich, free-draining soil. Adaptable to most pH levels; unlike bigleaf hydrangeas the white flower colour is not affected by soil pH. A pot with a working drainage hole is non-negotiable for this species — even free-draining mix will turn soggy in a closed planter. If you love the look of a decorative pot without a hole, use it as a cachepot around an inner nursery pot you can lift out to water.

Humidity and temperature

Smooth Hydrangea 'Incrediball' sits happiest at around 50-70% humidity and -37 to 30°C (-35 to 86°F). A North American native shrub at home in the moderate to moist air of woodland-edge plantings; tolerates ordinary garden humidity well. If you keep the room above year-round and avoid placing the plant near a cold draught, a hot radiator, or an air-conditioning vent, you have already handled the two biggest indoor stressors.

Fertilising

Feed smooth hydrangea 'incrediball' sparingly. Feed once in early spring with a balanced slow-release shrub fertiliser as growth begins. Light feeding plus correct pruning keeps stems strong enough to hold the giant heads. Skip fertiliser entirely on a stressed, recently-repotted, or actively wilting plant — fertiliser salts make damage worse, not better. Wait for a round of healthy new growth before resuming a feeding rhythm.

Common problems

Below are the issues we see most often on smooth hydrangea 'incrediball' in the Growli community. Each is annotated with the most common cause so you know where to start.

• Flopping heads (less than older types) — Bred for stronger stems than 'Annabelle' but the huge heads can still bend in heavy rain; cut back to about 15-25 cm in early spring to build a sturdy framework.
• Wilting in sun and drought — Big soft leaves and flowers wilt fast when dry; site with afternoon shade, mulch and water deeply during heat.
• Weak stems from over-shade or over-feeding — Too little light or excess nitrogen gives lax stems; grow in part to full sun and feed lightly.
• Late frost damage to new shoots — Blooms on new wood so it recovers, but a hard late frost can nip early growth; it will reflush and still flower that summer.

Propagation

Easy from softwood cuttings in early summer or by division of the clump; also self-suckers. 'Abetwo' is patent-protected, so commercial propagation is restricted. Propagation is the cheapest, most satisfying way to expand a collection — and it doubles as insurance against losing a mature plant to an accident. Take a backup cutting once the parent is established and healthy.

Toxicity to pets

Smooth Hydrangea 'Incrediball' is toxic to pets. ASPCA lists Hydrangea as toxic to cats, dogs and horses. The leaves, buds and flowers contain cyanogenic glycosides; ingestion of significant amounts can cause vomiting, diarrhoea and lethargy. If you keep cats, dogs, or curious children in the house, weigh placement carefully — a high shelf or a hanging planter is enough for casual safety. For severe ingestion incidents, call your local vet and the ASPCA Animal Poison Control Center (in the US, 888-426-4435).

Pet-safety status is sourced from the ASPCA Toxic and Non-Toxic Plant List, which catalogues the most-asked-about plants for cats, dogs, and horses.

Smooth Hydrangea 'Incrediball' deep-dive guides

Every aspect of smooth hydrangea 'incrediball' care, each with its own calibrated guide:

• Smooth Hydrangea 'Incrediball' watering schedule
• Smooth Hydrangea 'Incrediball' light requirements
• Best soil mix for smooth hydrangea 'incrediball'
• Smooth Hydrangea 'Incrediball' fertilizing guide
• When to repot smooth hydrangea 'incrediball'
• How to propagate smooth hydrangea 'incrediball'
• Smooth Hydrangea 'Incrediball' growth rate & size
• Smooth Hydrangea 'Incrediball' cold hardiness
• Smooth Hydrangea 'Incrediball' temperature & humidity
• Is smooth hydrangea 'incrediball' toxic to cats & dogs?
• Is smooth hydrangea 'incrediball' toxic to cats?
• Is smooth hydrangea 'incrediball' toxic to dogs?
• Getting smooth hydrangea 'incrediball' to bloom

Featured in these plant shortlists

Smooth Hydrangea 'Incrediball' qualifies for 6 curated Growli shortlists — each one filtered objectively from our structured plant-care library, so the selection is consistent and checkable:

• Best plants for a north-facing window — Houseplants for a north-facing window: bright, even, indirect light and no scorching direct sun. Each pick verified against its documented light needs.
• Best drought-tolerant houseplants — Houseplants that prefer to dry out — forgiving of forgotten watering and ideal for travel or busy weeks.
• Best humidity-loving houseplants — Houseplants that thrive in a bathroom, kitchen, or by a humidifier — selected by documented humidity preference.
• Best flowering houseplants — Indoor plants grown for their blooms — selected from the flowering species in Growli’s plant-care library.
• Houseplants toxic to cats & dogs — The common houseplants the ASPCA lists as toxic to cats and dogs — the ones to keep out of reach, each with its symptoms and a safe alternative.
• Best houseplants for a cool room — Houseplants that tolerate cool conditions down to about 10°C — for an unheated spare room, hallway, porch or a home kept cool.
• Browse all 29 plant shortlists — pet-safe, low-light, drought-tolerant and more

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Smooth Hydrangea 'Incrediball' is also commonly called Incrediball Hydrangea.

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