Hydrangea Tree

Tree with Flowers

Hydrangea Tree (Paniculata Grandiflora)

The Hydrangea Tree is the perfect yard tree. This tree with flowers is covered with masses of snow-white flowers that are ever-changing as they age. Cold-hardy Hydrangea is a reliable bloomer.

PeeGee Hydrangea, trained to a large, single trunk for quick, upright growth. This plant is well-loved by generations of gardeners and for good reason: in August and September it produces huge conical trusses of double flowers--up to 18in long--that are rich creamy white and fade gradually to shades of pink and then brown.

The foliage is a dark green that shows off the flowers to good effect. On its own it makes a broad shrub to 12ft high and 10-15ft wide. Some gardeners prune it up to create a small Hydrangea Tree. It flowers on new growth and so can be pruned in spring to make a smaller plant; this also produces the largest flowers. PeeGee Hydrangea is one of the best varieties for cutting and for drying.

Growing Guide

Light/Watering: Most varieties thrive in full sun in the North, but in the South require afternoon shade, and H. serrata 'Blue Billow' prefers full to part shade everywhere. Moist soils that do not dry out are best; do not plant in hot, dry, exposed sites. Mulch to conserve moisture and buffer soil temperatures.

Fertilizer/Soil and pH: Fertilize once in spring with a formulation for acid-loving plants. Soils should be moist but well drained, and rich in organic matter. In some varieties (H. macrophylla and H. serrata), flower color is determined by the pH of the soil; at low pH (acid soils) flowers will be blue and at higher pH, flowers will be pink. Generally, a pH below 5.0 results in deep, vivid blues and as the pH rises the flowers range from blue to lavender to mauve to a vivid deep pink at pH 7.0 (neutral). The pH determines the availability of aluminum in the soil; this element is more readily available in acid soils, and this availability results in the blue flower color. Since phosphorus ties up aluminum in soils, using a fertilizer low in this nutrient will aid in attaining blue flowers. If pink flowers are desired and your soil is acid, simply add lime to raise the pH and use a balanced fertilizer. Aluminum sulfate will lower pH if blue flowers are desired.

Pests/Diseases: None serious for the Hydrangea Tree. Occasionally powdery mildew will infect the foliage, especially in humid areas with poor air circulation. Treat with an appropriate fungicide if the problem is serious, and be sure to rake up and destroy all fallen foliage from your Hyandrea Tree in the autumn.

Companions: Old-fashioned tawny Daylilies are a classic combination with the PeeGee or Hydrangea Tree (H. paniculata 'Grandiflora'). Astilbes and Oriental Lilies in shades of rose, pink, and white are lovely with the shrubby Hydrangeas.

Reflowering: Regularly deadheading the blooms of H. macrophylla Endless Summer™ and H. m. Blushing Bride™ helps encourage repeat bloom on the current year's growth. You may cut the first flowering stems of H. arborescens 'Annabelle' and hang to dry for arrangements; rebloom may then occur in August or September. Dried flowers from the Hydrangea Tree are lovely.

Transplanting: Young plants may be transplanted when dormant in early spring; larger Hydranges Tree varieties are difficult to move once established, but it can be done. Prune top growth after transplanting to reduce water loss.

End of Season Care: Rake up and destroy any fallen foliage that was infected by powdery mildew or other fungi. You may wrap H. macrophylla varieties with burlap or other protective covering to help preserve flower buds through a cold winter.

Early Spring: Prune Hydrangea arborescens 'Annabelle' back to the ground, and prune tree form Hydrangeas now, removing lower suckers and up to half of the older top growth. Prune out any deadwood from all varieties. Check soil pH and adjust up or down if needed for desired flower color of H. macrophylla and H. serrata. Feed plants with a fertilizer for acid-lovers. Complete any transplanting before leaves unfurl.

Mid-Spring: Mulch plants after soil has warmed to conserve moisture and buffer soil temperatures. Watch for powdery mildew and treat as needed.

Summer: As soon as blooms fade, remove old flowering stems from of H. serrata 'Blue Billow', 'Fuji Waterfall', 'Miranda', 'Pretty Maiden', and 'Preziosa', H. macrophylla 'Big Daddy' and 'Nikko Blue', and H. quercifolia (Oakleaf Hydrangea). Cut flowering stems from H. arborescens 'Annabelle' and hang to dry if desired.

Fall: Remove and destroy any fallen foliage that was infected by powdery mildew. If desired, wrap H. macrophylla varieties with burlap or other material to help flower buds overwinter in colder climates.

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