There are some important principles of pruning that you need to keep in mind to be successful.
Why prune? . To maintain the health of a plant, (removing dead, diseased or damaged wood). Another reason may be to encourage vigorous and bushy growth. Finally, regular pruning, when done correctly, will improve the supply of strong, young growth, which in turn will produce a greater amount of flowers or fruit.
When do you prune? Avoid too little or too much pruning. The routine removal of weak, diseased or dead limbs can be accomplished at any time during the year without negative effect on the tree or shrub. However, growth is maximized and wound closure is faster if pruning takes place before the spring growth flush.
Make the proper pruning cut. The cuts should be made just outside the branch collar. The branch collar contains trunk or parent branch tissue and should not be damaged or removed. Damage or removal of the branch collar creates an entry for unwanted diseases and pests and requires preventative measures.
Principles of pruning. There are two: formative and gradual renovation. Formative pruning aims to produce a balanced framework of strong, evenly spaced stems that permits maximum light and air to reach the entire plant.Gradual renovation is for rejuvenating an old, overgrown plant. You should remove deadwood and one third of the oldest stems or branches and cut back the remaining branches by one third. Do this for three years to get an overgrown plant back to its prime.
A light pruning after planting will ensure balanced growth, best done during a dormant stage. If a young shrub does not have a balance framework, cut back hard. Then select the strongest, most evenly spaced branches to form the new framework.
Timing is important for pruning. Pruning at the wrong time can take away next years flowers and weakens the plant. See the list below for specific plant recommendations.
Variety Bloom Season When to Prune Buddleia (butterfly bush) Summer Early spring, cut back in early spring for better flowering Campsis (trumpet vine) Late Summer Spring, head back to 3 or 4 buds Caryopteris (bluebeard) Summer to Fall Early spring, cut back in early spring for better flowering
Forsythia (forsythia) Early Spring After flowering, pinch back, blooms on old wood
Evergreens Summer to Fall Mid-Spring Hibiscus (rose of Sharon) Summer to Fall Early spring, head back to 2 or 3 buds in spring for larger flowers
Hydrangea macrophylla (big leaf hydrangea) Summer After flowering, flower buds are over-wintered on previous years growth, prune right after done blooming
Hydrangea (hydrangea) Summer Early spring, head back in midsummer for second flowering
Lonicera japonica (honeysuckle vine) Summer Early spring, head back 3 or 4 buds Magnolia (magnolia) Early Spring After flowering, flower buds are over-wintered on previous years growth, prune right after done blooming Philadelphus
(mock orange) Early Summer After flowering
Potentilla Summer to Frost Late Winter Rhododendron (rhododendron)andAzaleas Spring After flowering, flower buds are over-wintered on previous years growth, prune right after done blooming
Syringa (lilac) Spring After flowering, flower buds are over-wintered on previous years growth, prune right after done blooming Spiraea (spirea) Spring to Summer After flowering, pruning current years growth will promote second flowering Tamarix ramosissima (tamarix) Mid to late Summer Habit and flowering display are improved if it is cut back to the ground each winter Weigela (weigela) Spring