The hydrangea is an attractive large leaf plant that can be used for foundation plantings, shrub borders or as specimen plants in the garden. If you are looking for a beautiful blooming shrub with flowers that last, this is it. As a bonus, caring for them is very easy. There are several types of hydrangea that are hardy in our harsh Minnesota climate. If you are planting one "up north", be sure to check the USDA Hardiness Zone information provided on each variety listed below. This is also where you will find any hints on how to prune or winter the specific varieties. We have listed all the varieties commonly sold in our area and considered hardy. Some only need occasional light pruning. Others are only root hardy and will need extensive pruning each season.Hydrangea blooms are made up of clusters of small flowers. The size, color and shape of the flowers vary from variety to variety. Hydrangea blooms contain showy sterile flowers and less conspicuous fertile flowers. They also vary as to season of bloom. As a group, they are all considered resistant to insect and disease problems, although they may have an occasional bout of fungal leaf spot, aphids or scale.
White or Creamy Hydrangea Varieties
Hydrangea paniculata 'Grandiflora' The unusual name of this plant is taken from the initials of its species and variety, paniculata 'Grandiflora.' It is also known as a panicle hydrangea. PeeGee is a vigorous variety that is hardy to Zone 3. It has large, showy conical-shaped blooms in August and September. They open a creamy white and, in a few weeks, fade to an attractive bronze-pink that holds well into the fall. In our climate, the shrub will grow 8-10 feet in height and width. Peegee hydrangeas prefer loamy, evenly-moist, well-drained soil. They are adaptable when it comes to pH and do well in full sun to partial shade. They bloom on new wood so any pruning should be done in spring. Because PeeGee hydrangeas are so hardy, there usually isn't much dieback.
Hydrangea paniculata ‘compact’ Compact form of PeeGee hydrangea with smaller foliage and flowers. Grows to 6 feet tall and 6 feet wide
Hydrangea paniculata 'Limelight' While it is closely related to PeeGee hydrangea, Limelight is hardy to Zone 4. It differs from PeeGee by blooming later and having exquisite bright lime-green flowers. It forms a rounded shrub that will grow 6-8 feet tall and 6 feet wide. Be sure to give it plenty of space to grow. Limelight grows well in partial shade to full sun. It is stunning when grown tucked under large, open shade trees where it will provide late summer and early fall bloom. 'Limelight' flowers form on new wood and should be pruned in early spring. It thrives in a well-drained loamy soil and tolerates a wide range of pH.
Hydrangea arborescens 'Annabelle' Also known as a Snowball hydrangea (or smooth hydrangea), Annabelles have huge, symmetrical blooms in June and July. Hardy to Zone 3, it can grow 4-5 feet tall and 3-5 feet wide. It is probably the showiest hydrangea in the garden with creamy white blooms that are often more than 8 inches across. Annabelle prefers rich, well-drained soil that stays consistently moist. It is tolerant of a wide range of soil pH and does best in partial shade. If it is planted in full sun, be sure to provide adequate moisture or the leaves will droop. Annabelle blooms on new wood and needs to be pruned back to within a foot or two of the ground each spring just as the new buds begin to emerge on the lower stems.
Hydrangea quercifolia This one is really marginal here, but you might have luck with a sheltered location and good winter protection. In our climate, it grows 3-4 feet wide and tall. It is prized for it's large, handsome oak-shaped leaves and cream-colored long panicle blooms. Prefers a cool, moist growing environment. Hardy to Zone 5. Plant in sun to light shade. Oak leaf hydrangeas have red fall color.
Hydrangea anomala subsp. petiolaris Climbing hydrangeas are for the patient, optimistic gardener. They are slow to start, sometimes taking several years to get going. Once the roots are well-established, they are vigorous, vining up stucco, brick, fences or trees with glossy, bright green leaves and creamy white flowers in June and July. Climbing hydrangeas require rich, well-drained soil and do well in partial shade. They will eventually grow 20-30 feet in length and require winter protection of the root system (a foot of straw, leaves or hay). Zone 5 hardiness.
Hydrangea paniculata ‘Kyushu’ A vigorous upright shrub with large lacy flower panicles held above glossy green foliage. Kyushu grows 6-8 feet tall and 5 feet wide.
Non-White Hydrangea Varieties
Most native soils (and water) are fairly alkaline in our area and the soil has to be acidified to get blue flowers. The safest way to acidify the soil is with elemental sulfur. Because sulfur doesn't work quickly, gardeners often resort to acidifying the soil with aluminum sulfate. It works quickly, but with repeated use, the heavy metals will build up and damage the roots of the hydrangea.
Discovered in a Minnesota Nursery, Endless Summer blooms on both old and new wood. The flowers are pink in alkaline soils, and blue in acid soils. In our climate, Endless Summer will grow to 3’-5’ high and wide. Blooms should show by late July. Some winter protection is a good idea; light pruning in early spring to shape the plant may remove some buds, but the plant will bloom on new wood.
Pink Diamond Hydrangea paniculata 'Pink Diamond' A panicle hydrangea (with cone-shaped blooms), Pink Diamond grows 3-4 feet wide and tall. It has a neat, mounding habit. It blooms in July and August with large medium-pink flowers. Blooms on new growth. Prune in early spring. Plant in moist, well-drained soil and full sun to light shade. Hardy to Zone 4.
Hydrangea paniculata ‘DVPinky’ An amazing hydrangea with two-toned flower heads. Large 12” – 16” flowers emerge white then turn pink. The dark green foliage provides a great contrast for the flowers. This Hydrangea grows to 8 feet tall and 8 feet wide.
Hydrangea paniculata ‘Bulk’ A new early blooming paniculata hydrangea with conical flowers similar to ‘Tradiva’ this plants flowers emerge white, then quickly mature to a rich deep pink. The plant grows 6 to 8 feet tall and 4 to 6 feet wide.
© Bachman's 2008