Keys To Planting A Hydrangea Bush

Tips on growing hydrangea shrubs, including climate, planting location, watering and soil recommendations for optimal growing conditions.

The hydrangea is a semi-hardy shrub that has pink, blue, or white flowers. They grow best in the southern parts of the country; although depending upon the variety, they can be hardy up to Zone 5. Hydrangeas prefer a temperate climate, with no temperature extremes. They should be protected from strong winds in winter and too much sun in the summer. Depending on the variety, the hydrangea may grow up to ten feet tall, so allow plenty of room in the landscape plan for the mature plant, as overcrowding is a sure way to have sickly plants.

Hydrangeas should be planted in a location that gets good morning and late afternoon sun. They should be protected from the strong midday and early afternoon sun, if possible. This can be accomplished by planting them under tall trees or an arbor, where they will receive dappled shade at midday.

The soil in which they are planted should be rich in organic matter, well drained, and somewhat acidic. For best results, make sure the hydrangea plants have a constant supply of moisture. Mulching with a two-inch layer of organic matter such as shredded wood bark or compost is a good way to insure constant moisture and nutrients for the shrubs. Plant them in the spring if the area has hard freezes in the winter. If the ground seldom freezes in winter, they may be planted anytime from fall to spring.

Dig a hole deep enough to accommodate the rootball of the hydrangea. Gently remove the shrub from its pot by upending the pot and holding the rootball where the stem of the plant goes into the soil. Gently tap or shake to pot to loosen the shrub's rootball from the pot. After the pot is removed, put your other hand on the bottom of the rootball and turn right side up. If the plant is rootbound, gently squeeze the rootball until the roots are loosened. Holding the plant by the rootball, place it gently in the hole and fill in around it with loose dirt. Firm the dirt around the plant and water well, adding more dirt and firming again if necessary. Spread the mulch evenly around the plant, being careful not to get it too close to the stem of the plant. Keep the soil evenly moist but not soggy for several weeks until the shrub is well established.

The flower color of some varieties of hydrangea is influenced by the acidity or alkalinity of the soil. More acidic soil will make blue-flowered varieties bloom a deeper and truer shade of blue, and will cause red-flowered varieties to bloom lavender. Alkaline soil will help the red-flowered varieties bloom a true red or rose. White-flowering varieties will not change color very much, except for the small male flowers in the center of the flower cluster of some varieties.

To make the soil more acidic, add aluminum sulfate to the soil by watering with a solution of 1/4 ounce of aluminum sulfate and 1/4 ounce of sulphate of iron per gallon of water. Do not apply more than two gallons of this solution per year. For alkaline soil, spread 1/4 to 1/2 pound of lime around the shrub and water in well. The lime does not have to be mixed into the soil; it will work its way in. Be careful not to use too much lime, or the plant will develop an iron deficiency. To get a plant that has both blue and red flowers, water with the aluminum sulfate solution on one side of the plant, and spread lime on the other side of the plant. Be patient, as it will take time for the flower color to change.

It will not be necessary to prune the hydrangea the first year it is planted. After that, it should be pruned in the late winter or early spring. Cut off the dead flower heads, being careful not to cut off too much of the stem. If too much of the stem is cut, new flower buds will be pruned away also. Prune away any weak or dead limbs.

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