Garden Talk - Coping with confusing hydrangeas

Many local gardeners enjoy one or more hydrangeas among their shrubs, and many of us admit to occasional confusion about maintaining these lovely plants. There are lots of different hydrangeas, so remembering what we have and when to prune can be challenging.

Experts tend to stress knowing whether your hydrangea blooms on old wood (last year?s growth) or new. However, some varieties bloom on both, and not all gardeners are certain which kind they have!

If you have a smooth hydrangea such as ?Annabelle? or ?Invincibelle,? it blooms on new growth. Any desired pruning of these should, ideally, be completed in late winter.

Hydrangeas with cone-shaped flower clusters, such as ?Limelight? and ?Vanilla Strawberry,? also bloom on new growth. However, guidelines for these suggest that pruning through early April is fine if you need to control the shrub?s size. If you have older panicle specimens in need of rejuvenation, though, the largest stems should be cut near ground level in late winter.

Confused yet?! It gets a little worse.

The largest category is bigleaf hydrangeas. Our native oakleaf hydrangea is found here. Because it blooms on old wood, wait until blooms just begin to fade before doing any desired pruning.

Bigleaf hydrangeas also include older cultivars blooming only on old growth, such as ?Forever Pink? and ?Nikko Blue.? If you have tried to raise these, you have probably experienced frustration. They just don?t do too well in Iowa.

However, newer cultivars of bigleaf hydrangeas such as ?Endless Summer? do perform well in Iowa. These bloom on both old and new growth, so gardeners should wait until the shrubs leaf out to identify and prune out any dead wood.

Hydrangeas are too beautiful to ignore, so taking a little time to understand the particularity of your specimen is worthwhile. If you are thinking of purchasing and planting a new hydrangea, be aware that there is considerable range in the size and light requirements of different varieties. Take time for a little research before shopping, and you will reap the rewards of suitability and beautiful blooms.