Prune to keep hydrangeas blooming
Posted on Sat, Mar. 11, 2006 on CC Times
By Kathy Van Mullekom
Hydrangeas are prized plants in the garden. Their white, pink and blue blooms are used as fresh-cut flowers in bouquets or as dried accents in wreaths.
But, over the years, a hydrangea bush grows big, oftentimes out of bounds. The stems get heavy, weighted down by bunches of blooms that make the plant droop to the ground, especially after a heavy summer rain.
Now is the time to grab pruners and put that bush back in its place.
on the species, hydrangeas grow as vines, shrubs and small trees, says Michael Dirr in his book "Hydrangeas for
Hydrangea macrophylla -- commonly called "mophead hydrangea" for its huge ball-shaped blooms -- flowers on growth that developed the previous year. Nikko Blue is a popular one in this category. Lacecap hydrangeas, those frilly-looking ones with what looks like white lace around pink or blue centers, belong to the macrophylla clan.
Hydrangea quercifolia -- known as oakleaf hydrangea for its oak leaf-shaped foliage -- also flowers on last year's wood, but it seldom needs pruning. Snow Queen and Alice are names you often hear in this family.
Other hydrangeas such as PeeGee (H. paniculata) and Annabelle (H. arborescens) flower on new growth, so you can cut them back to the ground now and enjoy beaucoup blooms this summer.
Climbing hydrangea, or H. anomala, needs little, if any, pruning; snip it lightly to control growth and shape.
Then, there's the modern-day Endless Summer, an H. macrophylla that blooms on new and old growth. It's really a fool-proof plant.
Your old-fashioned mophead, however, needs a little tender loving care, so we asked Virginia extension agent Jim Orband to demonstrate how to properly prune a H. macrophylla growing.
Old vs. new wood
Annually, remove the oldest wood, which is straw-colored and scaly looking. Newer wood is darker and fresher in appearance. Prune the oldest wood back to the ground, moving around the plant as you work. This automatically thins out your bush, and it may be all you need to do to the plant if it's a young specimen. You can also snip off old flower heads at this time.
As you remove the oldest wood, cut the stems back to the ground. Make your pruning cuts on a slanted angle, close to the crown (the part of the plant where the roots and stem meet, usually at soil level), so the cuts shed water. You'll also see new vegetation emerging, which helps rejuvenate your pruned plant. Let the cuts heal naturally.
Prune to lighten weight
As you work around the plant, you'll see vegetative buds forming at the tips of stems. New shoots with flower buds form along the stem, just below that vegetative bud. If your hydrangea droops from too many flowers on weak stems, you can prune one third of the stems back to a shorter length. This process -- called heading back -- forces the plant to develop sturdier, stiffer branches. Work around the plant, pruning these stems at staggered heights; prune above a bud so it breaks and becomes a new shoot to fill in the area.
Shape stems so growth goes upward. Remove rubbing and crossing stems on a hydrangea to let air and light into the plant, helping reduce disease and insect problems. Opening up the interior parts of the plant also allows more light, which produces more sugars, which results in more flowers.
When you prune any of your trees and shrubs, remember to:
· Use sharp, clean tools. Bypass pruners make sharp, clean cuts. To discourage the spread of disease among plants, disinfect your cutting tools in a mild solution of bleach and water, then wipe the tools dry before using them on other plants.
· Eliminate bad stuff. Prune to remove dead, diseased and damaged branches, as well as branches that rub against or cross over each other. A plant pruned so sunlight and air penetrates its interior is less likely to develop fungal diseases. Fungal spores like dark, damp spots.
· To prune or not to prune? Trees and shrubs need pruning only if they are too big for their spaces or have bad branching habits. For instance, there is no need to annually prune a crape myrtle; it will flower just fine without cutting it back. Avoid pruning a plant to keep its size under control; instead, replace that plant with a smaller variety.
· Prune properly. Plants have natural growth habits and look best when those natural shapes are allowed to form. When you prune a plant into a ball or cube, you create an outer veneer of green growth; no light reaches the interior of the plant, meaning no new growth happens there.
· Prune now. Butterfly bush, lantana, roses, camellias, glossy abelia, beautyberry, rose-of-Sharon, nandina, mahonia, holly, shade trees and evergreens can be safely pruned now.
· Prune later. Spring-blooming plants such as azaleas should be pruned as soon as they finish blooming; if you prune them now, you remove the flowers that will soon arrive.
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