Posts Tagged ‘arborescens’


November 4, 2010

Hydrangeas are beautiful ornamental plants, grown as shrubs, with large flower heads of white, pink, blue or purple. They will tolerate a wide range of soil, sun and moisture conditions.  Hydrangeas are native to Eastern and Southern Asia, and North and South America. The genus Hydrangea contains about 80 species of flowering plants, but only 5 of those are commonly available to buy in the United States.

1. Hydrangea paniculata is a native of Asia. It is the most cold hardy of the Hydrangeas, recommended for zones 4-7. It grows about 10-15 feet tall and is sometimes pruned into a tree shape. From late summer to early fall, it bears cone-shaped panicles of white flowers, up to 18 inches long. These are made up of small, fertile flowers and larger sterile flowers which gradually turn pink.

2. Hydrangea quercifolia is also known as the Oakleaf Hydrangea. It’s one of only 2 species native to the United States. Mostly found in moist woodlands, it grows 6 feet tall, and is recommended for zones 5-9.  Oakleaf has panicles of flowers similar to paniculata but smaller, about 10 inches long. They are white also, with the large sterile flowers turning pink as they age. Oakleaf also blooms a little earlier in the summer. This is also the only Hydrangea which displays fall color. The leaves, which resemble oak leaves, turn a bronze color in the fall. Some say that this plant is prized more for the foliage than the blooms.

3. Hydrangea arborescens, the only other United States native, is commonly called the Smooth Hydrangea. It is fairly cold hardy, and is found mostly in the Eastern side of the country. It can be grown in zones 4-9. Reaching 3-5 feet tall and wide, it blooms in mid-summer. The flowers are globe shaped, with dense, dull white flowers. As they age, the flowers turn to pale green. Some cultivars may have enormous flower heads, up to 1 foot wide. This type looks great when planted in a mass of the same kind.

4. Hydrangea anomala is different than the others. It’s a true clinging vine. Growing in zones 4-7, it can climb trees or structures up to 80’ tall. White lacecap flowers, up to 10 inches across appear in early to mid-summer. It’s probably not a good idea to grow this on a building, the aerial roots leave a residue that is difficult to remove.

5. Hydrangea macrophylla is, by far, the most widely used Hydrangea. A native of Japan, hardy to zone 6, there are more than 600 known cultivars. Macrophylla is also known as Bigleaf Hydrangea, French Hydrangea, Florist’s Hydrangea, and Garden Hydrangea.  Native to Japan, it has flowers that are white, but also can be pink, red, blue or purple. The flower heads of Macrophylla come in 2 different shapes. One is Mophead, which looks like what it sounds like; rounded, pom pom made up of larger sterile flowers, with smaller fertile flowers hidden in the middle. The other is Lacecap, which is flatter, with tiny fertile flowers in the center, and the showy sterile flowers around the edge. Plants grow 4-6 feet tall and wide, and bloom in early summer. The color of the flowers can be influenced by the pH of the soil. Acid soil will make the flowers blue, neutral will lead to cream flowers and pink or purple flowers will result from alkaline soil.