An Introduction: Pruning Basics

There is a lot of territory to cover here! This is going to be a very basic guide. My hope is to provide some introductory information about pruning.

So many of us are intimidated by the thought of pruning. We hear horror Cool and refreshing caladiums. Image licensed through ©iStockphoto.com/Magiana, photographer. stories of trees being "topped off" by utility companies or tree trimming services, only to be ruined in appearance. We know about shrubs that were so massacred that they never fully recovered. True enough, it is easy to ruin a plant by using improper pruning techniques, but it is not a wise idea to avoid pruning altogether, either. Sooner or later, shrubs, annuals, perennials, trees, and evergreens will require a trimming, so it is a good idea to head out to the garden with a bit of knowledge in the cranium as well as pruners in the hand.

Whether you realize it or not, you probably are already practicing pruning. If you pinch-out the center growth of annuals to encourage bushiness, if you trim back a delphinium after blooming or pinch a mum to promote fullness, you are in essence practicing the art of pruning. Most of us aren't afraid to give herbaceous plants such as annuals and perennials their needed haircuts, but we break out in a cold sweat when we consider trimming fruiting plants, trees, and other ornamentals.

There are many reasons why we prune plants. To maintain appearance and size would probably be the top reason for pruning. Keeping a plant healthy by removing storm or disease-damaged limbs would also be another reason for pruning. If you grow any fruit trees, you already know that pruning promotes better fruiting and one of the primary reasons for pruning a fruiting tree would be to open up the center to allow more light in for better fruit blossom set and also to contain the growth to make harvesting easier by providing lower-growing limbs on the tree. We prune grapes to maintain productivity. Roses are pruned to also maintain the vigor and blossoming of the plant. The trick is to make the cuts at the proper time and at the proper place on the plant, tree, or shrub.

Some General Guidelines For Pruning

1. Generally speaking, pruning after the bloom time of an ornamental shrub or tree is safe.

2. Prune anything that blooms on old wood after bloom time. Example: Old heirloom roses that bloom once.

3. Prune ornamental trees, shrubs, or vines that bloom before June after bloom time. Example: Lilac

4. Prune summer blooming trees, shrubs, or vines in earliest spring, before new growth. Example: Rose of Sharon

5. Exception: Some summer shrubs bloom on old wood. Prune these after they flower. Example: Late blooming azaleas

6. Non-blooming ornamentals can be pruned in the late winter, spring or summer. Shade trees would fall into this category.

7. Prune fruit trees in the late winter for shape and to open the center of the tree to light.

8. Prune fruit trees in this succession: Last to flower, prune first. First to flower, prune last.

9. Prune young trees later than older fruit trees.

10. Summer prune fruit trees to train tree growth or to remove unwanted or upright current season growth. Don't prune after July.

11. Pinch or shear the candles of pines and spruce by 1/3 to 1/2 as new candles appear to promote fullness. Don't cut into old wood, the tree will not fill in.

12. Prune grapes in the late winter, February to March.

13. Rejuvenate groundcovers such as liriope, pachysandra, and ivy in earliest spring to remove storm or winter damage.

14. Do not shear back most shrubs severely; thick outer growth will result, with thin to little interior growth. Cut back limbs and branches to thin growth, and to tip-back new growth while maintaining a natural appearance.

15. Try to cut back to a lateral stem to encourage branching.

16. Prune back plants, trees, and shrubs when moving. Moving a plant results in damage and loss to the roots, and a reduced root system. By trimming back a plant, you are compensating for the root loss. If top growth isn't trimmed back, the remaining roots may not be able to sustain the rest of the plant.

17. Limb-up trees to open up more sunlight to surrounding areas. This would be removing lower branches so the canopy starts higher up on the tree. BUT! Don't overdo it with evergreens such as spruce or pine!

18. Some trees leak sap when they are pruned: Maples, elms, flowering cherries and flowering plums are examples. Prune these after leaves have matured, not while leaf-out or while leaves are smaller. BUT: If you have no choice but to trim because of storm damage, etc., the tree or bush won't bleed to death. That's an old wive's tale. It will take longer to seal over, though.

19. Some plants resent heavy pruning, such as boxwood.

20. Juniper and arborvitae may die if severely pruned, and do not do well if more than 1/3 of their growth is removed.

21. The Rule of Thirds: Rejuvenate lilacs and other ornamental shrubs by thirds over a three-year timeframe: The first year, take a third of the oldest branches out, the second and third years, do the same. Only trim back top growth by about a fourth the first year.

22. Prune young trees later than older fruit trees.

23. Purple smoke bushes can be severely pruned back to contain growth in the late winter to early spring, but the plumes will be sacrificed.

24. Redtwig Dogwood have the showiest branches on the youngest stems. To maintain a good shape: Remove branches thumb-sized or larger, those with the least amount of red in them, in late winter to early spring to encourage new, red growth.

I hope this gives you the basics of pruning, and some confidence to boot. Pruning isn't brain surgery, although it does take a bit of knowledge about plant habits. I hope this introduction takes some of the intimidation out of tackling this essential gardening task! For more information on pruning specific plants, how to cut back, and where to make the cuts, please get a good pruning guide, and above all else, one that is understandable! One last word: when in doubt, please contact the guy down the street who has gardened for years, a nurseryman or your extension agent. These are wonderful resource people, and they will be able to guide you in your pruning efforts!