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The latest Hydrangea breeding has produced a dizzying array of repeat flowering plants. Old-fashioned Hydrangeas set buds on the previous year’s growth, but the new Hydrangeas set flower buds on both old wood and new wood. In Portland, this means flowers from June through frost!
Love Hydrangeas but don’t have the space? Dwarf Hydrangeas are the answer. Most mature below 3’ and work well both for containers and in small garden spaces. Thanks to busy breeders, there are many to offer & here are a few:
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5050 SE Stark, Portland, OR
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Genus: Hydrangea from the Greek hydor meaning water, and aggeion, meaning vessel; a reference to cup-shaped fruit
Common Name: Hydrangea
Origin: China, Japan, Himalayas, Philippines, Indonesia, North and South America
Characteristics: About 100 species of shrubs, small trees or vines.
Two types of flowers are present on most Hydrangeas – fertile & sterile.
Fertile flowers are small and inconspicuous, and are usually found near the center of a cluster.
Sterile flowers are large and showy. Flowers are held in differing cluster formations.
Mophead – Round or dome-shape clusters of mostly large sterile flowers hide fertile flowers beneath. Blue, pink, lavender, green, white & combinations of these colors are available. Find mopheads on Hydrangea arborescens, Hydrangea macrophylla and Hydrangea serrata.
Lacecap – Flat round clusters of small fertile flowers edged by larger sterile flowers available in white, pink, lavender and blue. Find lacecaps on Hydrangea aspera, Hydrangea macrophylla and Hydrangea serrata, as well as the climbing Hydrangeas, H. anomala petiolaris, H. integrifolia & H. seemanii.
Panicle/Cone - Long cone-shape clusters of white green or pink flowers. Some are so full of big sterile flowers that small fertile flowers disappear. Others are more open & have a lacy appearance. Find cone flowers on Hydrangea paniculata and Hydrangea quercifolia.
Leaves are deciduous or evergreen and vary from simple, opposite or in whorls of three, oval or toothed, smooth or serrated. Many Hydrangea varieties develop lovely red to dark purple & mahogany fall color. Peely bark adds winter interest on some species.
Blue & pink flowers of Bigleaf Hydrangeas, Hydrangea macrophylla change color depending on soil pH.
Soils west of the Cascades are typically acidic, so Hydrangeas are typically blue when planted in the ground.
To Change Colors:
pH Flower Color
Culture: Most Hydrangeas perform best when planted in dappled or afternoon shade. Those in full sun often burn and require extra watering.
Pee Gee Hydrangeas (H. paniculata), and Oak Leaf Hydrangeas (H. quercifolia) are exceptions that can be planted in sunny spots but will still perform well in part shade. Soil should be consistently moist and well-drained. Cold tolerance varies.
Fertilizing: For blue flowers, use fertilizer for acid-loving plants. Use rose & flower food for all other hydrangeas. In all cases, follow the package directions for whatever food you choose.
Remove dead flowers in fall or late winter. Count 2 leaf-sets beneath the flower cluster and cut just above the second set. Repeat-blooming Hydrangeas can be dead-headed as old flowers fade.
Hydrangea arborescens blooms on new wood, so prune branches to knee-level in late winter.
Rejuvenating or down-sizing large Hydrangeas – in late winter, take a long look at the overall structure of the plant.
Make 3-5 thinning cuts evenly through the body of the plant, choosing the branches are the most offending and cut them back to a major branch or to the ground.
After each cut, step back and choose the next wisely.
Remove dead wood, and branches that are growing toward the interior of the plant.
This type of careful pruning encourages growth in the interior & from the base during spring.
Next, remove dead flowers and cut back branch tips. Count 2 leaf nodes down from branch tips and cut above the second node. This ensures summer flowers.
Pests & Diseases: Hydrangeas are prone to fungal problems, but they are typically not life-threatening. Leaf Spots and Powdery Mildew are the most common diseases in Portland, and they can often be avoided by increasing soil drainage and air circulation in the environment of the plant. If plants become diseased, remove affected foliage, remove all leaves from beneath the plant in fall when leaves drop naturally, and mulch the ground under the plant. Fungicides are available in addition to cultural treatment.
Succulent new growth attracts slugs, aphids and deer. All can distort and stunt growth. Slugs can be effectively controlled with bait or beer, aphids can be washed off with water or insecticidal soap, and there are several sprays out there that deter deer.