After our colder winter months it is time to start thinking about pruning the shrubs in the yard to remove any cold damage or just to renovate, reduce size and prepare them for the summer growing season. We were lucky this year and did not have much serious cold weather or damage to our more tropical plants. It is never a good idea to heavily shear shrubs during the colder winter months and so when spring arrives it is a good time to get everything back into shape.
Removal of dead, weak or cold damaged wood, and disease and insect infested wood is an effective way to stop the spread of disease and insects to other plant parts or neighboring plants. This will be especially important for those cold damaged plants in your landscape which can easily develop disease problems as the damaged wood begins to rot. This in turn can attract insects. Always disinfect your pruning tools after pruning diseased wood, using a weak bleach solution, to prevent the disease from being spread to healthy wood. Your pruning should be followed by an application of fungicide on the plant to protect the healthy wood and new growth from any invasion of active disease organisms on your plants.
To rejuvenate old shrubs, trim to remove old stems and branches. This can be done every year and is a good procedure if the plant has become leggy or is growing out of the bounds of your gardens. Most shrubs are pruned to maintain or develop a desired size or form. Selective pruning can shape plants and produce either a thin or thick plant. Plants can be renovated with pruning by either heading back or thinning. Heading back is the selective cutting of the ends of branches to a bud. This procedure produces a denser shrub because it increases the number of shoots and leaves. When heading back make the cut on a slight angle, 1/4 inch above a healthy bud. The bud should be facing the direction preferred for new growth.
Thinning is the complete removal of branches back to the large lateral branches, the main trunk or to the ground. Thinning gives a plant an open and natural appearance and encourages healthy new growth.
We prune ornamental shrubs to improve their health and appearance. You should prune overgrown plants back gradually, over a period of years, as severe pruning can damage plants. Constant shrub shearing can also kill. Regularly shearing shrubs to the same height with gas shears will weaken them, make them leggy and susceptible to disease and insect problems eventually kill them. Yet, hedge shearing has become the norm. People actually expect all of their shrubs to look like square boxes, round spheres or cones and umbrellas. They call it the “manicured look”. And because everyone is doing it they think it’s the right way to do it. It’s not! You can get away with it for a number of years and since the ruining process is so slow, when things start to go wrong no one thinks of the pruning practices as the problem. When you shear shrubs regularly you expose them to unnatural conditions. It is a bad horticultural practice to remove the terminal (end of branches) buds week after week, year after year. A plant only has so many axil buds and dormant nodes to replace those lost to pruning. This new growth is important for plant health as plants get their food (sugar) from the sun through their leaves during the process of photosynthesis. As new growth occurs, the hedge shearer cuts it off so as to maintain the manicured look and they trim off the food delivery system used for future food production. This food is used to produce more plant tissue and most of it goes to the root system. So imagine the poor plant with no food to the roots for overall vigor and then you use up all axil buds and dormant nodes for new leaf growth – well I think you get the picture.
Plants pruned into different shapes creating landscape oddities, such as animals, are called a topiary. Or you can grow plants against a wall known as an espalier, which requires a special pruning technique. Plants trained in this manner are specimen plants and not all plants are adaptable to these techniques. Pyracantha, loquat and podocarpus are a few that make excellent espalier plants.
Flowering plants should be pruned at the proper time of year. Spring flowering plants such as azaleas or gardenias should be pruned immediately after flowering. They set flower buds on the previous season’s growth and the buds overwinter on this older growth. Pruning these plants in late summer or just before spring flowering would remove a greater portion of the flower buds and thus future flowers. Plants that flower on current season’s growth such as hibiscus, rose, oleander or bougainvillea should be pruned while dormant or before a new flush of spring growth. Most evergreens such as podocarpus, holly or arboricola can be pruned anytime.
For some shrubs, such as gardenia or croton, you should not use hedge shears but cut each branch separately using hand shears. This will maintain a neat informal shrub that retains its natural shape. A properly pruned shrub is a work of art.
The method of pruning hedges depends on the type of hedge desired. Informal hedges consist of a row of closely planted shrubs which are allowed to develop into their natural shape. Annual pruning consists of cutting just enough to maintain the desired height and width.
Formal or clipped hedges require continuous pruning during the growing season. The desired appearance of a formal hedge is a soft outline of foliage from the ground up. Two important things to remember when pruning formal hedges are (1) hedges should be clipped while new growth is green and succulent and (2) plants should be trimmed so the base of the hedge is wider than the top. It should also be noted that constant over shearing of hedges can cause the tips of branches to die back and develop disease. Cocoplum is especially susceptible to this problem. Be sure you have something to prune before you put your shears to the plant. Hedges pruned with a narrow base will lose lower leaves and branches because of insufficient light. This condition will worsen with age resulting in sparse growth at ground level and an unattractive hedge which will not give the desired privacy.
When the wrong shrub is planted in the wrong place, it is often necessary to over prune to keep the plants from interfering with each other and growing out of the bounds of the garden. To avoid this costly mistake, learn the mature size of the plants and then plant them in an area that will not require over pruning to maintain them in that area.
Your pruning tools should include the following:
Hand pruners – used to cut branches up to 1/4 inch in diameter.
Loppers – used for limbs up to 1 ½ inches in diameter.
Hedge shears – used to shear formal hedges.
Saws – used to cut branches too large to prune with loppers.
Pole saw and pruner – used to prune difficult to reach branches.
Chain saw – probably better left to the professionals