Smooth Hydrangea - The Ultimate Growing Guide
Grow this beautiful flowering shrub for long-lasting color in the landscape
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Smooth hydrangea (Hydrangea arborescens) is a hardy deciduous shrub. It has long-lasting flowers and a compact mounding habit that's versatile in any landscape. Also known as wild hydrangea or sevenbark, it is a native plant in the eastern and central United States. It grows in semi-shaded woodlands and along moist streambanks.
Most smooth hydrangea varieties have large globe-shaped flowers similar to bigleaf hydrangea. Others have flat-topped lacecap blooms with clusters of tiny fertile florets surrounded by showier sterile flowers. Its blooms attract beneficial pollinators and it's a host plant for the hydrangea sphinx moth caterpillar. Use it in a woodland landscape, native garden, mass planting, shrub border or containers.
SMOOTH HYDRANGEA CARE & PLANTING
How to plant: The best time to plant smooth hydrangea is during cooler months in spring or fall. Choose a site with at least 4 to 6 hours of morning sunlight and afternoon shade, or dappled sunlight throughout the day. Follow these steps and space plants 2-1/2 to 5 feet apart, depending on the variety.
- Dig a hole that is just as deep and twice as wide as the root ball.
- Remove the plant from the nursery pot and tease out the roots if potbound.
- Set the plant in the hole with the top of the root ball level with the surrounding soil.
- Backfill the hole with soil and tamp down gently to remove air pockets. Water well.
- Apply a 2- to 3-inch layer of bark mulch around the base of the plants to help retain moisture and suppress weeds.
Soil: Smooth hydrangea performs best in rich, well-draining soil. For containers, use a high-quality all-purpose potting mix.
Watering: Smooth hydrangea prefers regular moisture for the best growth and flowering. Keep soil evenly moist but not soggy. Avoid overwatering to prevent powdery mildew, root rot or other diseases. Water more often during prolonged heat and dry spells.
Pruning: This hydrangea type blooms on the current season’s growth. Smooth hydrangea pruning should be minimal to allow plants to retain their natural shape and size. In early spring, remove any dead, diseased or broken branches and lightly shape plants as needed.
Fertilizing: Smooth hydrangea bushes need little or no supplemental fertilizer once established. If plants need a boost, fertilize in early spring with a granular slow-release shrub and tree fertilizer. Be sure to follow package instructions.
Mulching: Smooth hydrangea shrubs benefit from mulching, which will cool the root zone, retain moisture and suppress weeds. In early spring, place a 2- to 3-inch layer of compost or bark around the base of the plants. Keep mulch a few inches away from the trunk to avoid insect or other problems.
TRY THESE PROVEN WINNERS® VARIETIES
Plant some of these smooth hydrangea varieties in your landscape:
 | Incrediball® (H. arborescens) is an improved cultivar of ‘Annabelle’, with large, rounded flowers up to 12 inches across held upright on strong, sturdy stems. The snowy white flowers appear in mid-summer, aging to lush jade green, and persisting until frost.
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 | Invincibelle® Ruby (H. arborescens) has a compact bushy habit, lush dark green foliage, and two-toned flowers in shades of bright ruby red and silvery pink. This strong rebloomer produces continuous blooms for long-lasting, reliable color.
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 | Incrediball® Blush (H. arborescens) produces massive globe-shaped flowers on stout stems, reblooming from summer through fall. The soft pink blooms add a delicate touch to beds, borders and mass plantings.
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 | Invincibelle Wee White® (H. arborescens) is the first-ever dwarf type of ‘Annabelle’, reaching a maximum of 2 1/2 feet tall and wide at maturity. The petite plants produce rounded flowers on sturdy upright stems from early summer to frost, emerging blush pink before changing to creamy white. Use in mass plantings, as edging, or in containers.
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 | Invincibelle Limetta® (H. arborescens) offers refreshing summer color in the landscape, with a dwarf rounded habit that is versatile in foundation plantings, borders and containers. Spherical flowers are held upright on stout stems beginning in early summer. The blooms start out lime green, then lighten to a soft green-white before turning jade green for the rest of the growing season.
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 | Invincibelle Lace® (H. arborescens subsp. radiata) is a unique smooth hydrangea variety with dark ruby stems and elegant lacecap blooms. Rich plum-purple florets are complemented by soft white flowers for understated elegance. Plant in a shrub border, or as hedging for long-lasting color throughout summer.
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 | Invincibelle Sublime™ (H. arborescens) produces cloud-like mophead blooms that appear to float above the dark green foliage, held upright on strong stems. Intensely colored lime-green flowers add a refreshing touch to foundation plantings and beds from summer into fall. The flower heads are attractive in fresh or dried arrangements.
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 | Invincibelle Mini Mauvette® (H. arborescens) is a dwarf smooth hydrangea variety with uniquely colored mauve-purple flowers held upright on strong stems. The compact plants begin blooming in early summer, producing new flowers into fall for a captivating, long-lived display. Use in mass plantings, containers, or as a showy focal point.
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 | Invincibelle® Spirit II (H. arborescens) is an improved version of the original pink ‘Annabelle’ hydrangea, with dark green foliage, strong stems and large deep pink blooms that age to an attractive green. Waves of fresh flowers occur from summer through fall on reliable plants, thriving in most growing zones.
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Erin Schanen of The Impatient Gardener offers suggestions on how to choose the right hydrangea varieties for your yard.
SMOOTH HYDRANGEA FAQs
What is a smooth hydrangea?
Smooth hydrangea is a small- to medium-sized deciduous shrub native to the eastern United States. The peeling bark is produced in thin layers of different colors, hence the common name of sevenbark. This reliable shrub is one of the hardiest hydrangea types, with most varieties surviving to USDA zone 3.
Stacey Hirvela of Proven Winners Color Choice talks more about different smooth hydrangea varieties:
Can smooth hydrangeas take full sun?
This hydrangea species grows natively as an understory plant in shaded or semi-shaded moist areas. It performs best in partial shade with protection from hot afternoon sun, especially in hotter climates. Too much sun exposure can cause foliage burn and stress.
Do you cut back smooth hydrangeas?
Smooth hydrangea looks best when allowed to retain its natural shape and size. To invigorate new growth, plants can be cut back by 1/3 in early spring. See our guide to pruning hydrangea for tips.
What is the difference between smooth and bigleaf hydrangeas?
Smooth hydrangeas bloom on new wood and their flower color is unaffected by soil chemistry. While bigleaf hydrangeas (H. macrophylla) bloom on last season’s growth, offer a range of flower colors that vary with soil pH, and bloom earlier in the season, from late spring to mid-summer.
Skye Hamilton of Hamilton House Designs shares more tips on how to tell these two hydrangea types apart:
What is the lifespan of Hydrangea arborescens?
The lifespan of smooth hydrangea can vary, depending on the variety and growing conditions. In general, individual plants will live for 20 to 50 years.
Should I deadhead Hydrangea arborescens?
Removing spent blooms can encourage new flowers and more vigorous growth. Late-season flower heads can be left for winter interest. In early spring, remove old flowers left from the previous growing season before new growth emerges.
HOW TO USE SMOOTH HYDRANGEA IN YOUR LANDSCAPE
This versatile landscape shrub can be used in many ways. Here are some ideas:
- Add to foundation plantings with other shrubs that bloom at different times for season-long color.
- Showcase a dwarf hydrangea in a decorative pot as a patio focal point.
- Mass smooth hydrangea bushes along a slope as an effective erosion control solution.
- Use smooth hydrangea as an understory plant in a woodland garden.
- Plant a row of a full- to medium-sized variety as a flowering hedge to divide garden areas.
- Use this native hydrangea in a pollinator garden to support wildlife.
- Edge a pathway or border with a dwarf variety for weeks of continuous color.
- Use a smooth hydrangea specimen as a showy focal point in a bed or border.
COMPANION PLANTS
Combine smooth hydrangea alongside other plants with similar cultural needs of partial shade and well draining, moist soil.
For year-round color, use smooth hydrangea in a foundation planting in combination with other shrubs including:
- Perfecto Mundo® Double Purple reblooming azalea
- Sprinter® boxwood
- Montana Moss® juniper
- Double Play Big Bang® spirea
Plant smooth hydrangea in a semi-shaded mixed border with other plants such as:
- Dolce® ‘Toffee Tart’ coral bells
- Shadowland® ‘Autumn Frost’ hosta
- Scentlandia® sweetspire
- Midnight Express® redbud
Include smooth hydrangea in a late-season border alongside other plants with colorful fall flowers or foliage such as:
- Sunshine Blue® bluebeard
- Just Chill™ Double Mauve camellia
- Samurai Sword™ Japanese maple
- Fall in Love® 'Sweetly' Japanese anemone
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