Pruning is challenging for many gardeners.  There are so many different kinds of pruning techniques and rules for pruning that you are never confident about how and when to prune.  So before we explore the subject of tip pruning here are a three pruning basics to remember.

• If it flowers – Prune soon after flowering. If it flowers after Mid-August prune in late winter.
• Stop pruning and fertilizing all shrubs and trees by mid-August here in Memphis, TN
• Dead, Diseased or Damaged plant material can be removed at any time.

Tip pruning is a technique to make our plants branch out for a fuller appearance.  It comes to mind at this time of year because most of our spring blooming shrubs like azalea, weigelia, deutzia, quince, viburnum, forsythia, witch-hazel and spirea have bloomed and are pushing out new growth.  This new growth will often be a bit rangy with a long stem and a cluster of leaves at the tip.

This leggy growth is controlled by a plant hormone called auxin. The terminal bud (the bud at the end of a branch or twig) produces auxin. As long as the terminal bud is intact, auxin suppresses the growth of lateral buds and shoots below the terminal. When you remove the terminal bud by pruning, lateral buds and shoots below the pruning cut grow vigorously. The most vigorous new growth always occurs within 6 to 8 inches of the pruning cut.

One form of tip pruning is pinching.  While the growth is still tender you can simply use your fingers to pinch out one half to two thirds of the new growth just above a leaf or leaf node. This technique is often used on annuals like Zinnias or herbaceous perennials like salvia.  This causes them to branch and results in a more compact plant with more blooms.  If your plant is a woody perennial the stems of this tender new growth is tougher but you just follow the same process using a pruning tool.  When we cut flowers for a bouquet we are essentially tip pruning.

Because we tend to pay less attention to our flowering shrubs once they have finished blooming we may end up with a situation where we have rangy growth with little tufts of leaves on top of a slender stem above the bulk of our shrub.  If you like this airy appearance you need do nothing.  If you want a more compact plant you can tip prune these woody stems to shorten them and let them branch out again at a lower level.  If that new growth is also rangy you can cut again, but not after mid-August here in Memphis, TN.  When tip pruning you will want to make your cut lower than the surrounding foliage to allow room for the shoots that form at the point of your cut to grow upward.

Another option would be to follow the stem of rangy growth all the way back to a main branch or the trunk of the shrub and remove it completely.  This will thin out your shrub allowing for better air flow and more light to penetrate into the shrub, both of which are good for the plant.

Shearing our plants with hedge clippers is a form of indiscriminate tip pruning.  It is used to tightly control the size and shape of a plant.  Here you are not pruning back to a leaf node, in fact you are often cutting a leaf in half. You are focused only on cutting to a specific size or shape.  Shearing is often utilized in formal gardens and to create topiaries.

This technique results in a highly branched structure at the surface and a dense cover of leaves.  Inside the hedge is a scaffold of branches with virtually no leaves as light cannot penetrate through the lush exterior layer.  When creating a hedge it is recommended that you shape the sides of the hedge to be wider bottom and more narrow at the top to assure that light will reach the lower branch tips and not get shaded out.

Our plants do not require us to prune them they will do just fine on their own.  But as gardeners we can use pruning to help plants grow in a manner that is more pleasing to our personal aesthetic.  Hopefully these tips on tip pruning will become a more confident and successful gardener when you next consider pruning. 

MAY Gardening Activities

Plant    Annuals and perennials early in the month.  Warm season vegetables (seeds and transplants), zinnia seeds.  Continue planting gladiolas every 2 weeks for a succession of blooms. Choose and plant crepe myrtles in bloom so you can choose the desired color. Wait until night temperatures are regularly be above 60ᴼ F before planting caladium tubers. 

Lawn Care  Seed Bermuda.  Fertilize Bermuda and Zoysia lawns with complete fertilizer.   Mow lawns approximately 2 inches high.  Do not remove more than 1/3 of the leaf blade at each mowing.  Consider using mulching blade on mower. 

Prune Climbing roses at end of the month. Early May is a good time to cut back any woody perennials that need it, such as rosemary, rue, lavender, and Artemisia. Prune spring-flowering shrubs (azaleas, flowering quince, Forsythia and Loropetalum) soon after they finish flowering, but only if they need it. To keep them from looking like a meatball, follow the taller branches down into the shrub and cut just above a joint. 

Other Water deeply during weeks with less than 1 inch of rain. Stake tall plants. Don’t let weeds get started in the garden — take control early with mulches and proactive management.

Take Hydrangea cuttings and let root in coarse sand.  Spray for leaf rollers that disfigure your cannas. For an organic approach use products containing Bacillus thuringiensis (Bt). The nonorganic active ingredient Carbaryl sold most often as Sevin is very effective as well. Both should be sprayed only once the caterpillar is present and after each rain or when new caterpillar damage is noticed. Care must be taken to get the insecticide down into the rolled up leaves where the caterpillars are feeding. Remove seed pods from bulbs and irises.