COMMENTARY

Hydrangea’s time 
to shine

9/10/2013

Kelly Heidbreder

Hydrangea are the show stoppers of the neighborhood landscape right now, with plenty of blooms hanging heavy on their branches. These are my favorite flowering shrubs because they are so versatile. By blending different varieties, your blooms can last well into the first frost. Their heavy foliage make them a good choice as a foundation plant and many can of them grow more than 5 feet tall, making them another good choice as a backdrop for your other flowering favorites.

But these beauties are causing some confusion in your backyard because my email is full of questions about pruning and changing colors. So, let’s see what we can do about that.

 

Pruning

The most common time to prune most hydrangea will be in the spring. The best rule of thumb is to prune it immediately after it blooms, then you will be sure not to cut off any future flowers. Mopheads and Lacecaps need to be pruned in late summer. Oakleaf hydrangea is best pruned in early spring. Pee Gee can be thinned or cut back in late winter or early spring. Some set their blooms on last year’s stems. Other varieties start blooming on the current season’s growth.

If you are thinning your hydrangea, you will get more blooms. Larger bloom clusters will form if you cut out half of the original stems. The plant will work harder on growing blooms and not stems and leaves. Pinching off new buds will encourage more clusters of smaller flowers. You might think feeding them will also make them heavier bloomers. But in some cases, feeding them while they are blooming will create fewer blooms.

 

A new color

Hydrangea are sensitive to the nutrients in their soil. It shows up in the color of their blooms. If you have pink flowers and you want to turn them blue, you need to change the pH of your soil. Add aluminum sulfate to the soil for blue flowers and lime for pink flowers. Mix in four to five ounces of sulfur per square yard during the growing season to lower your pH and turn your flowers blue. Also mix about eight ounces of aluminum sulphate into the soil to get things going quicker.

Spread it out to three feedings a season in the early spring, early summer and fall. It may take about three seasons before your plant will catch on. Keep applying the soil amendments, or the blooms won’t stay pink or blue. If you want the color to stay vibrant, try burying an oversized pot in the ground below the soil line. Then, fill it with the amended soil for your hydrangea and let it spread out into its own underground container garden. This will help keep the amendments from leaching into the surrounding soil and help your blooms stay vibrant.

Alkaline or sweet soil will change their bloom to pink. Dig in about three ounces of lime per square yard two times a year to keep your soil neutral and those blooms pink. Seven is the magic number. Seven is neutral. Soil with a pH of 6.5 is a good goal for red flowers and 7.5 will give you blue ones so get to the garden center and pick up a test kit to find out how much sulphur or lime you will have to add to get the perfect punch of color on those blossoms. You will have to apply the additive two or three times a year.

Contact Kelly Heidbreder at getgrowing@gmail.com