Color of Hydrangeas

Overview

While many flowers simply blossom into one particular color no matter what, gardeners can influence the color outcome of hydrangea flowers depending on particular soil requirements. This makes hydrangeas a versatile addition to the garden both with greater color selection within one plant as well as a tolerance to more than one type of soil. Identify all colors of hydrangeas and care requirements that will keep those colors vivid.

Pink or Blue Hydrangeas

French hydrangeas (Hydrangea macrophylla), also referred to as bigleaf hydrangeas, are available in blue or pink blossom options. Whether flowers develop into pink or blue hues is wholly dependent upon the pH level (acidity or alkalinity) of the soil they grow in. The occurrence of aluminum creates blue flowers. The lack of aluminum yields pink flowers. Since alkaline soils makes aluminum inaccessible to the hydrangea plant, these soils produce pink blooms. Acid soils produce blue blossoms, according to the Clemson University Extension. Test your soil before making any changes to pH and determine the degree of change needed before applying amendments; contact anl extension agent or professional to determine the appropriate rate of application for your soil type and pH level.

Soil pH Change for Pink Hydrangeas

For pink hydrangeas, create an alkaline soil environment with a pH above 7.0. To increase alkalinity of your soil, you must increase the pH, thereby making the soil less acid. Application of lime is the suggested amendment method, according to the Clemson University Extension. Lime is a form of limestone that is ground to varying degrees of fineness. Treat your soil with limestone during autumn or winter for successful alkalinity and wait to plant for a duration of two to three months. For optimal results, combine limestone with moist soil as dry soil will not respond.

Soil pH Change for Blue Hydrangeas

For blue hydrangeas you need to decrease the pH of your soil, making it more acid and less alkaline. For acid soil, the most widely used method is application of aluminum sulfate, which acidifies soil immediately. For successful pH change, do not simply place the aluminum sulfate on top of soil, but thoroughly combine it below the soil surface for uniform distribution. Handle aluminum sulfate with care as it will burn plants in cases of direct contact, according to the Clemson University Extension.

Other Species and Colors

Oakleaf hydrangeas (Hydrangea quercifolia) are shrubs that display white flowers that become a pink color in maturity, according to the Clemson University Extension. Climbing hydrangeas (Hydrangea anomala) are vines that display clustered white blossoms. Peegee hydrangeas (Hydrangea paniculata) are large shrubs or small trees that display large, clustered, white blooms that also fade to pink during the autumn season.

Considerations

Careful care of hydrangeas means the display of vivid colors instead of dull hues. Grow hydrangeas in sun during the morning hours and in shaded conditions during afternoons. Plant in well-drained soil high in organic content, according to the Clemson University Extension. Avoid excessively hot and cold temperatures as these extremes may injure hydrangeas; damage from the cold may inhibit plants from blooming.

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About this Author

Tarah Damask's writing career, beginning in 2003, includes experience as a fashion writer/editor for Neiman Marcus, short fiction publications in "North Texas Review," a self-published novel, band biographies, charter school curriculum, and articles for eHow. She has a love for words and is an avid observer. Damask holds a Master of Arts in English and creative writing from the University of North Texas.