Hydrangeas and Azaleas

Show these southern landscape staples a little love for the best blooms!

By Brantley Snipes, PLA, MLA, MHS: owner of Brantley Snipes Landscape and Design, Inc.

I am not biased when it comes to selecting the best bloom season in our Delta Landscapes, as I believe that all our seasons are the best season. Yet, there is something magical about early summers in the Delta. We’ve just experienced our landscapes spring back to life, and we watch in awe as they transition into full bloom throughout the summer. This transformation is best represented by two of our most common Southern landscape staples, the azalea and the hydrangea. However, often these beloved shrubs are not pruned correctly and therefore, fail to achieve peak bloom or growth habit. Here are some tips to ensure you are pruning your azaleas and hydrangeas correctly.

Hydrangeas

Hydrangeas have mystified Delta gardeners for decades and now that the market is full of different varieties, I’m afraid the equation has not gotten any simpler. Hydrangeas are just starting to hit their bloom stride in May and June in the Delta. If planted in the correct location, hydrangeas really don’t need much pruning.

The first ones we will see bloom are our mophead/bigleaf/lacecap and oakleaf hydrangeas. These belong in the Hydrangea macrophylla and Hydrangea quercifolia family, which is important to note as these are pruned differently from other hydrangeas. These hydrangeas create blooms on old wood early in the summer. If you prune them in the fall or spring, you will remove the future blooms. Our old-wood hydrangeas should be pruned immediately after they bloom. To reduce height and encourage stem vitality, remove the oldest and largest canes at ground level. Again, power shears should never be used on your hydrangeas. Instead, use your hand snips to gently remove the old blooms.

Other hydrangeas that are popular in the Delta can be pruned during the spring and winter, as they bloom on new wood. These hydrangeas include: H. paniculata (our common Limelight Hydrangea), H. arborescens and H. serrata. The blooms on these hydrangea varieties are white and appear later in the summer; therefore, they can be pruned in late fall or early spring. In fact, light pruning of these hydrangeas can increase vigor and produce more blooms.

To recap, if your hydrangea blooms early in the summer, prune immediately after it blooms and do not prune in the fall or spring. If your hydrangea blooms later in the summer, prune in the fall or early spring to aid in performance.  If you are pruning correctly and still not enjoying any blooms, check to make sure your hydrangea is receiving enough sunlight and that it did not experience any winter damage, such as a late frost in early spring.

Azaleas

By now, our azaleas have finished blooming and are settling into their role as a beautiful evergreen shrub in your landscape. May and June are the ideal months to prune them. There are three levels of azalea pruning: deadheading, light trimming, and renewal pruning. All levels should be done with hand snips or hand loppers. You should never take power shears to your azaleas. And, azaleas should never be pruned in a box!

When you finish pruning, apply an azalea/camellia fertilizer, which can be found at our local garden and nursery centers. Avoid fertilizing and pruning your azaleas in the fall. The Delta grows our Southern Indica Azaleas the best. Remember that azaleas like filtered shade and acidic soils and do not like wet feet (or root systems).

Deadheading: Removing the dead blooms off your shrub to generate some more height on your azalea.

Light trimming: This is all that’s needed when you want to remove some height and/or reshape it. The best way is to visualize the height and shape of your azalea, draw an imaginary line in your visualization and then get to snipping. Your imaginary line should follow the natural growth habit of your azalea and the main branches within the canopy.

Renewal pruning: Save this for azaleas that have been left alone for several seasons and have become leggy, displaying an incomplete canopy. Remove the top third of the plant, again following the natural growth pattern. This should remove most of the existing leaf canopy and allow light to reach into the branch structure, so the new growth can begin and fill in a full canopy from ground to bloom.