Hydrangeas: Summer-Long Color and Evolving Beauty

Hydrangeas: Summer-Long Color and Evolving Beauty

No shrub group has transformed more recently than Hydrangeas. For generations, they were dependable but unexciting—large, pale flower heads for midsummer filler. Then 2003 brought Endless Summer™, a compact Bigleaf Hydrangea with glorious blue-edged pink blossoms from early summer through fall—six full months in mild regions. Exceptionally hardy, it blooms reliably from Zone 4 to 9 (Minneapolis to Houston).

Our Picks from the New Hydrangeas

• Blushing Bride™: Another ever-blooming Hydrangea.
• Climbing Hydrangea (H. anomala petiolaris): Longtime favorite—grows/flowers even in northern exposure. Large, heavy vine with lateral branches up to 3 ft from support. Superb on large shade trees, walls, stonewalls. Reddish-brown peeling bark attractive in winter. Slow first couple years, then vigorous. Blooms in 3–5 years.
• Everlasting™ Revolution: Reblooming kaleidoscope of changing colors.
• Cityline® Mars: New generation, bicolored deep rose-and-white flowers.

Stalwarts of the Summer Garden

Innovation hasn't diminished long-lived durability. Depending on type, Hydrangeas adapt from shade to full sun. Bold foliage textures and prolonged bloom make them ideal for structuring and enclosing a summer garden. Flowers and foliage age gracefully, taking on rosy tints—a melancholy autumn pleasure.

Hydrangea Care Summary

• Light/Watering: Most thrive in full sun in North; South needs afternoon shade. H. serrata 'Blue Billow' prefers full to part shade everywhere. Moist, non-drying soils best; avoid hot, dry, exposed sites. Mulch to conserve moisture and buffer temperature.
• Fertilizer/Soil/pH: Fertilize once in spring with acid-lover formulation. Soils moist, well-drained, rich in organic matter. In H. macrophylla and H. serrata, flower color depends on soil pH: low pH (acid) = blue; higher pH = pink. Generally, pH <5.0 = deep blue; as pH rises, blue → lavender → mauve → vivid deep pink at pH 7.0 (neutral). pH determines aluminum availability (more in acid soils → blue). Phosphorus ties up aluminum; low-phosphorus fertilizer aids blue flowers. For pink in acid soil: add lime to raise pH, use balanced fertilizer. Aluminum sulfate lowers pH for blue.
• Pests/Diseases: None serious. Occasionally powdery mildew in humid areas with poor air circulation—treat with fungicide if serious; rake/destroy fallen foliage in autumn.
• Companions: Old-fashioned tawny Daylilies classic with PeeGee/Tree Hydrangea (H. paniculata 'Grandiflora'). Astilbes and Oriental Lilies in rose, pink, white lovely with shrubby Hydrangeas.
• Pruning: Varies by variety (some flower on old wood, some on new).
  • Prune after bloom (late summer) before next season's buds set: H. serrata 'Blue Billow', 'Fuji Waterfall', 'Miranda', 'Pretty Maiden', 'Preziosa', H. macrophylla 'Big Daddy' and 'Nikko Blue', H. quercifolia (Oakleaf). Remove deadwood as new growth emerges in spring.
  • Prune late winter/early spring (flower on current season's growth): H. paniculata 'Tardiva', 'Grandiflora' (PeeGee), 'Limelight', 'Pink Diamond', H. arborescens 'Annabelle'. Most cut 'Annabelle' to ground for compactness. 'Grandiflora' and 'Pink Diamond' pruned to maintain single-stem tree form.
  • Climbing Hydrangea: Prune as needed after bloom.
• Reflowering: Deadhead H. macrophylla Endless Summer™ and Blushing Bride™ regularly to encourage repeat bloom on current growth. Cut first flowering stems of 'Annabelle', hang to dry; rebloom may occur Aug/Sept.
• Transplanting: Young plants when dormant in early spring; larger tree-forms difficult but possible. Prune top growth after transplanting to reduce water loss.
• End-of-Season Care: Rake/destroy fallen foliage infected by powdery mildew/fungi. May wrap H. macrophylla with burlap/protective covering to preserve flower buds through cold winter.

Calendar of Care

Early Spring: Prune 'Annabelle' to ground; prune tree-form Hydrangeas (remove lower suckers, up to half older top growth). Prune deadwood all varieties. Check/adjust soil pH for desired flower color of H. macrophylla and H. serrata. Feed with acid-lover fertilizer. Complete transplanting before leaves unfurl.
Mid-Spring: Mulch after soil warms. Watch for powdery mildew; treat as needed.
Summer: As blooms fade, remove old flowering stems from old-wood bloomers (list above). Cut 'Annabelle' stems for drying if desired.
Fall: Remove/destroy infected fallen foliage. Optionally wrap H. macrophylla with burlap to help flower buds overwinter.