PRUNING is another frequent question. Hydrangeas, like azaleas and many other plants that bloom on older wood, can be a heartbreak of a plant if we don't get it right. The macrophylla hydrangea, which is the big leaf hydrangea, or the mop head hydrangea blooms on second year wood. You must know that. So many people will come into the Gibbs Gardens visitor center and say Mr. Gibbs, why are my hydrangeas not blooming? The first thing he asks is “when do you prune them?” They will say “oh, every year, like I am supposed to, I cut them back to the ground.” Well that is the worst thing you can do because you no longer have second year wood for it to bloom on. If one has a hydrangea that has nine canes, select three of those canes to prune, prune the oldest out, leave the other six canes to produce blooms. Scatter the canes you prune throughout the plant so it looks natural. By doing this you will always have blooms, but leave enough second year wood. That is important, it’s a great tip. It’s smart to take out the oldest wood because that is where the greatest risk of disease and insect pressure is going to be and a wonderful way to keep the plant clean, keep it healthy and ensure that we get blooms every year.
Eric wonders what resource material Jim might recommend for hydrangeas. Without question, Jim’s favorite the book is Michael Dirr’s book “Hydrangeas for American Gardens” (Hydrangeas for American Gardens from Timber Press). In this book there are hundreds and hundreds of varieties listed. Dirr tells how to grow hydrangeas, one can go through and search for the hydrangea you want for your particular site. In Jim’s mind there is no question everybody needs this book in their gardening library.