A question from a friend asking what he should do with a hydrangea received over Easter is the topic for this week’s column. As this is the proper time to prune these attractive shrubs we’ll cover that topic as well.
Hydrangea macrophylla is the plant featuring those big, beautiful blooms in the stores in early April. They’ve been forced in greenhouses to be in peak condition for the occasion, so don’t be cruel and move yours outside in weather that will be chilly for awhile yet.
Instead, keep it in a bright spot inside, don’t let it dry out, and in mid May start setting it outside in a sheltered nook for a few hours each day.
Gradually increase the time over a week. Then you can remove it from the pot and plant in a protected area with a handful of bone meal and shovelful of sheep manure.
These hydrangeas are touch and go with regard to hardiness in our zone. Sometimes they’ll survive over the winter. You can increase its chances by providing a light mulch of straw or branches in late November.
Big-leaf hydrangeas only produce flowers on old-wood. To keep yours healthy and uncrowded, prune it back in late April or early May once the leaf buds begin to grow. If you wait longer you may cause damage to the soft growth of the lengthening branches. Cut the plant back to about 4"-6" from the ground to stimulate shorter and denser branching.
As a point of interest, hydrangea blooms are one of the easiest cut flowers to order through a florist for a special event. They come in a wide variety of colours and breeders are continually improving them.
The colours of hydrangeas can vary not only from plant to plant, but the same specimen can change from year to year. As some blooms age they may retain some antique shades of pink, green, burgundy or even blue.
I always recommend aluminum sulfate for fertilizing hydrangeas, as that helps make the soil acidic for the production of darker, more blue shades. For pink shades add lime.
Hydrangea Macrophylla Konigstein is a new introduction for 2011. The description of this cultivar on the Hydrangeas Plus website is of a five-foot tall plant that produces fabulous darkest red to purple blooms with dark green and deeply veined leaves.