Plant of the Month

Hydrangea Macrophylla

Origin: The Hydrangea macrophylla is a species of Hydrangea native to Japan. Common names include Bigleaf Hydrangea, French Hydrangea, Lacecap Hydrangea, Mophead Hydrangea, Penny Mac and Hortensia.

Size: The hydrangea’s size, on average is 3’ to 6’ in height. The width of the plant is usually equal to or greater than its height.

Blooming Time Span:
This is a great plant for mid to late summer. It typically blooms from July through August, giving some variations of the plant the common name “endless summer”.

Diseases/Insects:
There are few diseases or insects that hinder the hydrangea’s growth, and there aren’t any which are serious threats. They do have some susceptibility to bud blight, bacterial wilt, leaf spot, and mildew. Aphids are occasional visitors.

Care Instructions:
Make certain not to prune the hydrangea until after it has completely finished flowering for the summer. Pruning before it is done flowering will result in less flowers blooming in the season to come.
The hydrangea requires a moist environment, but be certain not to over water it.
Discoloration of the leaves may be an indication of too much or too little water.
Snap off any dead/discolored leaves to allow new growth to replace them.

‘Nikko Blue’ and ‘Endless Summer’:
The hydrangea is a very showy plant with an abundance of flowers. The rich colors and strong presence make it a ‘must-have’ in any landscape.

The flower of the Hydrangea macrophylla is especially interesting. Depending on the acidity of the soil it’s grown in, the color of the flower changes. If the soil is more acidic, the plant will bloom with blue flowers. Conversely, if the soil is more alkaline, or base, the flowers will bloom pink.

(Nikko Blue in acidic soil)

(Nikko Blue in alkaline {base} soil)

Would you like to change the color of your hydrangea flowers?

If the soil has a pH of 5.5 or lower, the flowers will be blue. If the pH is higher than 5.5, the flowers will be pink. To change the color of your flower from pink to blue, add aluminum sulfate to the soil, which actually lowers the pH of the soil. You can purchase aluminum sulfate at most garden centers.

Growing Zones (Hardiness) for Hydrangea:

Temperature and placement can affect the growth habit of your plant. Hardiness is the ability to withstand harsh environmental conditions. The chart below indicates the temperature range in which your plant will fair the best, given the specified zone within which it’s located.

Please keep in mind that location can change how the temperature affects the plant. If the plant is planted to the south, the cold winter winds will not affect the plant in the same way that planting it to the north or west would.

Hardiness for Hydrangea macrophylla:
USDA Zone 6a: to -23.3° C (-10° F)
USDA Zone 6b: to -20.5° C (-5° F)
USDA Zone 7a: to -17.7° C (0° F)
USDA Zone 7b: to -14.9° C (5° F)
USDA Zone 8a: to -12.2° C (10° F)
USDA Zone 8b: to -9.4° C (15° F)
USDA Zone 9a: to -6.6° C (20° F)
USDA Zone 9b: to -3.8° C (25° F)