Q: When and how do I prune my camellias, azaleas, hydrangeas, roses and perennials?
A: Winter’s arrival on the Gulf Coast is not always trumpeted by cold, but you can be sure winter is here when gardeners sharpen their pruners. My father was an enthusiastic pruner. I subscribed to the theory that his fervor was the result of all of that repressed gardening energy during winter. The plants went dormant but he did not. My mother was known to stand in front of favored shrubs to protect them from his enthusiasm.
For gardeners like my father, the Extension Agents at the Alabama Extension Office at 1070 Schillinger Road offer a free pruning workshop and demonstration every February. Call their office at 251-574-8445 for the date and information.
But to your question, the short answer is … there is no short answer. You have asked a big question. The when and how for pruning blooming shrubs and perennials is guided by bloom time and, in some cases, plant species, cultivars or variety. But here are a few guides to help:
• The gardener’s golden rule for pruning is the “May Day Rule.” Plants like azaleas, which bloom before May 1, are pruned immediately following the bloom cycle. Later pruning would remove next year’s blooms. Plants such as roses, which bloom May 1 and after, are pruned in late winter or early spring of the following year.
• Another way to remember when to prune roses is what we’ll call the “Valentine’s Rule.” Roses are the flower of Valentine’s Day, the date when Gulf Coast gardeners can get ready to prune their roses. Prune roses when the threat of freeze has passed and at the first sign of new growth emerging. If only we could stop there.
• But what about plants like camellias, which bloom in three different seasons depending on species and variety? Again, pruning is controlled by the bloom cycle. So for camellia fall and winter bloomers (before May 1), prune in spring after blooming — but wait until after the danger of freeze to avoid cold damage. If a late freeze surprises, when pruning cuts are fresh, consider using a protective freeze cloth, especially on young plants. For late spring blooming camellias (still before May 1), prune as soon as the blooms fade. Camellias only need maintenance pruning.
• For every good rule there are exceptions, right? Let’s talk hydrangeas. Pruning hydrangeas is dependent on both species/cultivar and flower development. Some hydrangeas bloom on “old wood” while others bloom on “new wood,” and this trait determines the time to prune. “Old wood” means last year’s stems, and “new wood” means the new growth emerging after winter dormancy for the current year.
Old-wood bloomers like oakleaf and bigleaf hydrangea (the mopheads) must be pruned immediately after current flowering, and always before next year’s flower buds begin forming, usually from August to October. Do not cut back the entire plant, since doing so will remove all of next year’s blooms. Only general maintenance pruning on bigleaf and oakleaf hydrangeas is needed. Remove all dead wood and cut about one-fourth of the oldest stems to the ground to improve plant vigor and shape.
• Those that bloom only on new wood, such as panicled hydrangeas like the popular summer-blooming Limelight (after May 1), should be pruned the following late winter or early spring to stimulate new stem growth needed for blooms. Panicled hydrangeas need annual pruning for continued blooming each season, and can be cut six inches to 12 inches from the ground, or half the plant’s height, every year.
• Just to throw all the rules into chaos, developers now offer a few bigleaf hydrangeas that bloom on both old and new wood. Read the plant information provided when you buy these new hydrangeas.
Some gardeners are offended by the naked legs of dormant oakleaf and bigleaf hydrangea. The panicled hydrangea allows this gardener to remove those offensively bare stalks. But hydrangeas like the panicled Limelight grow six to eight feet tall, and each year’s new limb growth is weak and can droop in a decidedly unladylike sprawl. Use a support to hold the stems upright, or allow the plant to re-establish its strength by leaving some older, stronger stems unpruned in order to retain the plant’s mature shape and provide mass to help hold the new stems. Under-planting with a low evergreen will hide those lasciviously naked winter legs and hold their frilly skirts of summer bloom off the ground.
• Perennials die back when dormant, so the gardener does not have to cut them back except to clean up the planting bed, a good idea if the perennials ended the season with diseases. Perennials such as rudbeckia or coneflower left to develop seedpods will feed the birds and provide seeds for saving to replant or give away.
All bulbs, regardless of bloom time, should be left standing until the leaf straps fade, because they are storing energy for the next year’s bloom. Gardeners who don’t appreciate the aesthetic of the dormant perennial bed can whack faded perennials down for winter. Unless the plants are diseased, the trimmings can go into the compost pile.