The Hydrangea (Hydrangea macrophylla) is a blooming shrub that is hardy to USDA horticultural zone 6. However, some Hydrangea shrubs do not grow well in certain areas of the country or even in a particular landscape. This is because Hydrangeas prefer deep, moist soil as well as some protection from the hottest sun. Also, Hydrangeas bloom on wood and new buds produced over the previous season. If a Hydrangea is planted in an area where it is not suited, the new flower buds may suffer damage from a late freeze in the spring. This severely restricts bloom production.
Look for the location in your landscape where you wish to plant your Hydrangea. The location should get between four and six hours of morning sun and protection from the hottest afternoon sun. Look at the size of the space available for planting an Hydrangea. Many varieties grow up to four feet high and wide while others can get much larger. Good air circulation is important to prevent mildew problems, and the site must be located where you can apply supplemental water during the season.
Find out your USDA Horticultural Zone by looking at a USDA Horticultural Zone Map. This is important because some varieties of Hydrangeas may not be suitable for you planting zone, especially if you live where the ground freezes. Only choose varieties that are listed for your area. In every description of a Hydrangea variety you will find in a nursery, catalogue, or on line, you will find the zone or zones that is appropriate for that variety.
Purchase your Hydrangea from a local nursery if possible, because there is a good chance that the variety sold is suitable for your climate. Do not buy an Hydrangea to plant in your garden from a Florist. This is because florist Hydrangeas are grown in greenhouses under strict conditions to produce maximum blooms on small plants. These plants are usually not suitable for harsh outdoor conditions.
Buy a Hydrangea shrub with at least one or two blooms visible so you know what the flower color is and what to expect. Keep in mind that in some cases, the flower color can change from blue to pink, or pink to blue, depending on the pH level of the soil where planted.