You planted an Incrediball hydrangea expecting a modest shrub, only to watch it explode into a dense, 5-foot-wide ball of white blooms that dwarfs your garden path. This fast-growing hydrangea often surprises homeowners with its sheer size – and if you’re not prepared, it can quickly overtake beds, block walkways, or shade out neighboring plants.
As a horticulturist with over 15 years of hands-on experience cultivating hydrangeas across USDA zones 3–9, I’ve helped hundreds of gardeners manage – and maximize – Incrediball growth. You’ll learn exactly how big these shrubs get, what controls their size, and how to keep them thriving without becoming unruly.
This guide covers mature dimensions, growth rate, environmental factors, pruning strategies, and care tips to ensure your Incrediball hydrangea delivers stunning blooms without overwhelming your landscape.
Mature Size and Growth Expectations
Incrediball hydrangeas (Hydrangea arborescens ‘Abetwo’) are vigorous, fast-growing shrubs known for their exceptional cold hardiness and reliable flowering. At maturity, they typically reach 3 to 5 feet in height and spread 3 to 4 feet wide, though exceptional specimens in ideal conditions can exceed 5 feet in both dimensions.
Unlike older varieties such as ‘Annabelle’, Incrediball was specifically bred for stronger stems that support larger flower heads without flopping. This structural improvement allows the plant to maintain its full size and form even in rainy or windy conditions.
Growth occurs primarily in spring and early summer, with the plant adding 12 to 18 inches in height and width annually during its first few years. After establishment, growth slows slightly but remains steady, especially when provided with optimal soil and moisture.
| Growth Factor | Typical Impact on Size |
|---|---|
| Soil Quality | Rich, well-drained soil increases spread by up to 20% |
| Sun Exposure | Full sun promotes compact, dense growth; partial shade may lead to legginess |
| Watering Frequency | Consistent moisture supports maximum size; drought stunts growth |
| Hardiness Zone | Zones 3–8 allow full maturity; warmer zones may see faster initial growth |
What Influences Incrediball Hydrangea Size?
Several environmental and cultural factors directly affect how large your Incrediball hydrangea will grow. Understanding these variables helps you predict – and control – its ultimate footprint in your garden.
Sunlight plays a critical role. Plants receiving 6+ hours of direct sunlight daily tend to grow fuller and more compact, while those in deep shade may stretch upward in search of light, resulting in taller but sparser growth.
Soil composition is equally important. Incrediball thrives in moist, well-drained, organically rich soil with a slightly acidic to neutral pH (5.5–7.0). Heavy clay or sandy soils can limit root development, indirectly restricting overall size.
Water availability significantly impacts growth rate. These hydrangeas prefer consistent moisture, especially during the first two growing seasons. Drought stress not only reduces bloom production but can also limit vegetative growth by up to 30%.
Fertilization also matters. A balanced, slow-release fertilizer applied in early spring supports healthy expansion without encouraging excessive, weak growth. Over-fertilizing – particularly with high-nitrogen formulas – can lead to lush foliage at the expense of flowers and structural integrity.
| Care Practice | Effect on Plant Size |
|---|---|
| Full sun (6+ hours) | Promotes dense, compact form |
| Partial shade (3–6 hours) | May increase height but reduce fullness |
| Weekly deep watering | Supports maximum growth potential |
| Annual spring fertilization | Encourages steady, healthy expansion |
| Poor drainage | Limits root spread, stunts overall size |
Pruning for Size Control and Health
One of the biggest advantages of Incrediball hydrangeas is their on-old-wood flowering habit, meaning they set buds in late summer for the following year. This allows for strategic pruning without sacrificing blooms.
The best time to prune is late winter or early spring, just before new growth emerges. At this stage, you can remove up to one-third of the oldest stems to encourage rejuvenation and control spread.
For size management, focus on thinning rather than shearing. Remove select older stems at the base to open the center, improve air circulation, and reduce overall width. Avoid topping the plant, as this leads to weak, multi-stemmed regrowth and fewer flowers.
If your shrub has already outgrown its space, you can perform a more aggressive renewal pruning by cutting all stems back to 12–18 inches above ground. While this will eliminate flowers for one season, the plant will rebound with vigorous, manageable growth the following year.
Regular deadheading after blooming also helps maintain shape and redirect energy toward root and stem development rather than seed production.
Planting Tips to Maximize (or Limit) Growth
Where and how you plant your Incrediball hydrangea sets the stage for its long-term size. Proper spacing is critical – plant shrubs at least 4 feet apart to allow for mature spread without crowding.
Choose a site with morning sun and afternoon shade if you’re in a warmer climate (zones 7–8), as intense afternoon heat can stress the plant and reduce vigor. In cooler regions, full sun is ideal.
Amend planting holes with compost or well-rotted manure to boost organic matter and improve moisture retention. Ensure the top of the root ball sits level with the soil surface – planting too deep can suffocate roots and stunt growth.
Mulching with 2–3 inches of shredded bark helps retain moisture, regulate soil temperature, and suppress weeds that compete for nutrients. Keep mulch a few inches away from the base to prevent rot.
| Planting Consideration | Recommended Practice |
|---|---|
| Spacing | 4–5 feet apart for full maturity |
| Soil Amendment | Add compost or aged manure at planting |
| Mulching | 2–3 inches, kept away from stem |
| Initial Watering | Water deeply 2–3 times per week first year |
Common Misconceptions About Incrediball Size
Many gardeners assume Incrediball hydrangeas stay small because they’re often sold in 1-gallon containers at nurseries. However, these shrubs are fast growers and can double in size within two growing seasons.
Another myth is that all hydrangeas need constant shade. While Incrediball tolerates partial shade, it performs best in at least 6 hours of sunlight, which promotes stronger stems and larger blooms.
Some believe pruning will reduce flowering, but with Incrediball, proper pruning enhances both size control and bloom production. Unlike panicle or oakleaf hydrangeas, this variety blooms on old wood, so timing is key – but not prohibitive.
Finally, don’t confuse size with health. A large Incrediball isn’t necessarily overgrown – it’s likely thriving. The goal isn’t to keep it small, but to manage its size in harmony with your landscape design.
How Big Is Too Big? When to Take Action
An Incrediball hydrangea becomes problematic when it:
- Overhangs walkways or driveways
- Blocks windows or sightlines
- Shades out smaller perennials or groundcovers
- Requires frequent, unsightly pruning to contain
If your shrub exceeds 5 feet in width or begins to flop under the weight of its blooms, it’s time to intervene. Start with selective thinning in early spring. Remove the oldest, thickest stems to reduce bulk and encourage new, sturdy growth from the base.
For severely overgrown plants, consider renovation pruning – cutting all stems to 12 inches. Though you’ll miss a season of flowers, the plant will regenerate with renewed vigor and better proportions.
Alternatively, transplanting to a larger bed or border may be the best long-term solution if space allows.
Frequently Asked Questions
How fast do Incrediball hydrangeas grow each year?
Incrediball hydrangeas grow approximately 12 to 18 inches in height and width per year during their first few growing seasons. Growth slows slightly after establishment but remains steady with proper care.
Can I keep my Incrediball hydrangea small?
Yes, through annual spring pruning and selective thinning, you can maintain a more compact form. However, aggressive shearing is not recommended, as it weakens the plant and reduces flowering.
Do Incrediball hydrangeas bloom on old or new wood?
They bloom on old wood, meaning flower buds form in late summer for the following year. Prune in late winter or early spring to avoid cutting off buds.
What’s the best way to prevent flopping?
Ensure full sun exposure, avoid over-fertilizing with nitrogen, and prune selectively to maintain strong, upright stems. Incrediball’s sturdy structure naturally resists flopping compared to older varieties.
Can I grow Incrediball hydrangeas in containers?
Yes, but they require large pots (at least 18–24 inches in diameter), consistent watering, and annual root pruning to prevent becoming root-bound. Container growth may limit ultimate size to 3–4 feet.
Final Thoughts
Incrediball hydrangeas are among the most reliable and visually striking shrubs for temperate gardens, capable of reaching 3 to 5 feet in height and spread. Their size is manageable with proper planting, pruning, and care – turning potential overgrowth into a landscape asset.
By understanding their growth habits and responding with timely maintenance, you’ll enjoy years of lush foliage and massive, snowball-like blooms without sacrificing garden harmony.
