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Hydrangea, macrophylla 'Nikko Blue'

Magnificent, bright-blue flowers! A must for your butterfly garden!
'Nikko Blue' hydrangea is the most common class of hydrangea with bright, long-lasting blooms. The 'Nikko Blue' hydrangea has large, round flower heads that are a bold blue. The flowers bloom in late spring, over a rounded canopy of dense foliage. 'Nikko Blue' hydrangea have large, oval-shaped leaves that often taper to a point.

Hydrangeas are among the showiest of all the flowering shrubs, and the 'Nikko Blue' Hydrangea is a superstar. Spectacular in any landscape design, this dazzling shrub is versatile, vigorous and easy to cultivate. This shade of blue is rare to find in garden plants, but 'Nikko' delivers a deep blue that will be the focal point of your landscape. The flower color of the 'Nikko Blue' hydrangea depends on the acidity level of the soil. In acidic soil, this hydrangea has deep blue flowers, while in alkaline soil, the blooms tend to be lighter, and sometimes even pink. 'Nikko Blue' is an older vigorous cultivar which reaches 6 feet in height.

Plant Details +

Botanical Hydrangea macrophylla 'Nikko Blue'
Common Name Bigleaf Hydrangea
Family Hydrangeaceae (hydrangea Family)
Height 4-6'
Spacing 4-6'
Hardiness Zones 5-9
Exposure Partial shade to full sun. Hydrangeas benefit from some shade in the middle of the afternoon, especially in hotter regions.
Foliage Lustrous Rich Green Leaves
Flower Blue in acid soil; Pink in alkaline soil.
Bloomtime Mid-Summer

General Information +

General Characteristics: The 'Nikko Blue' hydrangea blooms on large buds formed on growth from the previous season. Because of this, any pruning should be done immediately after flowering. 'Nikko Blue' is best grown in rich, medium moisture, well-drained soil in part shade. Tolerates full sun only if grown with constant moisture. Soil pH affects flower color (blue color in highly acidic soils and pink color in slightly acidic to alkaline soils). Add aluminum sulfate to soil to make flowers bluer or add lime to soil to make flowers pinker (add any such soil amendments to plant root zone in late autumn or early spring). Bloom occurs on old wood. Prune any time after flowering by cutting back flowering stems to a pair of healthy buds. Prune out weak or winter-damaged stems in early spring. Only winter hardy to USDA Zone 5. Can be grown in Zone 5 with winter protection (e.g., mulch and burlap wrap), but may lose significant numbers of flower buds or die to the ground in harsh winters, thus respectively impairing or totally destroying the bloom for the following year. 'Nikko Blue' hydrangea grows best in fertile, well-drained soils. They are not very drought tolerant, and should be watered regularly during dry periods. The 'Nikko Blue' hydrangea prefers full sun, but should be given half shade in areas that have overly hot summers. This big leaf hydrangea cultivar is part of the Hortensia or mophead group (large sterile florets arranged in globular or "mophead"-like panicles). It is a deciduous shrub with a rounded habit which typically grows 4-6' tall. Features clusters of pink or blue florets in large, rounded, 4-5" panicles (corymbs) which bloom in June (often earlier than other varieties) for up to two months. Large, serrate, obovate to elliptic, lustrous, medium green foliage. Group or mass in a sheltered location of the shrub border. Great cut flower. Also a good specimen or accent for protected locations near homes or patios.

Planting/Care Instructions +

Planting Instructions: 'Nikko Blue' should be planted in moist, rich, well-drained soil. Dig a hole large enough to encompass the roots without bending or circling. Set the plant in place so the crown (part of the plant where the root meets the stem) is about 1-2 inches below the soil surface. When planting your 'Nikko Blue', the crown (where the stem meets the roots) should be placed just below ground level. Planting deeper can cause the roots to rot. Cover with soil to the original soil surface and water thoroughly. Once the shrub is placed in the hole, tamp the soil down around it and water. It is a good idea to mulch your hydrangea to help the soil to retain moisture. 'Nikko Blue' hydrangea requires moderate watering during the growing season. It should also be fertilized with a light fertilizer in March, May, and July.

Pests or Diseases: No serious insect or disease problems. Some susceptibility to bud blight, bacterial wilt, leaf spot and mildew. Aphids are occasional visitors.