By Todd Layt
Pruning ideas including utilizing modern machinery for efficient pruning
Whether it’s a tree, a shrub, a ground cover, a grass or strappy leaf plant, pruning is eventually required for all in an ornamental landscape. Modern landscape plants have been bred for less pruning, but with modern equipment should we really be pruning less? What are the best techniques and equipment for each plant category? This issue we look at ground covers, shrubs, grasses and strappy leaf plants. Next issue we look at tree pruning including coppicing.
Working our way up from ground covers to small trees, our modern ground covers are often more dense than landscape ground covers of the past. Breeders over the last 20 years have released many plants with shorter internodes. Grevillea groundcovers have become more prostrate, and there are now even dense prostrate Westringia ground covers. More prostrate will mean less vertical pruning, but keep an eye on the spread of these modern ground covers. Keeping them regularly in check by edging there lateral growth is essential, but with modern pruning equipment’s increased efficiency and ease of use why stop there. More frequent top pruning will result in tidier plants. Some groundcovers benefit from running a mower or brush cutter over them once a year.
In the USA in Texas, you can drive through suburbs in winter and see most of the Liriope, Mondo, and vine type plants like Asian Jasmine cut back with a lawn mower or brush cutter. Soon after in mid spring drive by and you will see vibrant clean foliage ground covers throughout Texas. Maybe it’s time for Australian maintenance companies to consider similar techniques. Vines particularly left unpruned for many years generally become unattractive. They may harbor wasps and rodents, experience foliage and branch dieback, and lose their landscape effectiveness. Prune out the top one-third of overgrown or elongated stems. Prune old mature stems that are declining in vigour by one-third or even more. Winter is the best time. Make sure the mower or brush cutter blades are sharp.
On the other hand, many modern ground cover plants may not require regular pruning to survive or to look reasonable, but to look spectacular or to achieve a more formal look, light pruning 4 to 6 times per year can produce amazing results. A couple of examples explain best. Grevillea juniperina or the popular Westringia groundcover Mundi can be pruned once per year for a native finish, or pruned 4 to 6 times per year for a tidy modern clean finish. In summer if you prune every month and a half, the finish is amazing, akin to a manicured lawn. Treat these natives like some exotics, and you get a more formal finish. Never prune back hard in summer as this can hurt the plant, but regular light tip pruning can be done year round in most parts of Australia. These days an argument could be made that regular light pruning with quick efficient machinery is just like regularly mowing the lawn.
Strappy Leaf plants and ornamental grasses are a major component of our modern landscape. Cutting these back is vastly different. Firstly you should use well sharpened implements such as knives, hand shears, or brush cutters. Hedging machines usually tear these plants, and the leaves quickly blunt the blades. Brush cutters also tear unless you keep the blade very sharp. It pays to have a couple of blades for a day’s work, sharpening them before use again. For Lomandra, Dianella, and most strappy leaf and grass plants in large scale plantings it is best to cut the plant back to no lower than 15 cm. This ensures the plant will survive. Avoid pruning in a drought, or in the middle of summer. Liriope can always be cut to the ground, preferably in winter.
Poa can be cut back very short in late winter, early spring, and autumn, never summer. Pennisetumn is best cut back in late winter, early spring, and can be cut back hard. In a garden situation, it may be more desirable to cut Dianella and Lomandra close to the ground. Usually, plants will survive that, but occasionally some drop out. To avoid dead plants, you can prune in a 2 step process. Cut all but about 10% of the leaves back just above the ground, leaving a few on one side longer. In a few weeks after the rest of the plant has started to reshoot, come back and trim the last few leaves off to the ground. Fine Leaf Lomandra plants such as Tanika, and compact Dianella plants such as Little Jess have reduced pruning in this category of plants to every 5 to 8 years, but pruning every 2 to 4 years or so in a garden situation certainly helps these plants look super fresh. Fine leaf Lomandra longifolia types, such as Tanika and Katrinus Deluxe also look spectacular when pruned into ball shapes.
Modern long reach hedge trimmers are the perfect tool for ground cover or shrub pruning. You do not need to bend, or move as often, making pruning not only more comfortable but more efficient. They have the potential to improve safety, by moving the trimmer further away from the operator. Pruning shrubs can easily be achieved with a light weight hedge trimmer, and some operators prefer these, but for taller operators, the long reach types maybe more suitable even for both shrubs and groundcovers. There are so many great brands of hedge trimmers to choose from these days. They are far more efficient making pruning so fast that more frequent hedging is now easy and most importantly cost effective. Some systems use a multi-tool system making them super versatile.
Just look at how many great brands I found by looking back at the last few issues of LC/LM magazine; Parklands, Stihl, Husqvarna, Oleo-mac, Maruyama , Efco, Bushranger, Kawasaki, Pellenc, Tanaka, Shindaiwa, Hitachi, and Honda. Whatever machine you use, or even if you use hand held shears, pruning frequency on shrubs depends on the desired look. If you what a formal hedge, then more frequent light pruning will result in a more manicured look. If you want a native or natural look, strategic pruning once a year is all that is needed. Leaving shrubs for more than a year unpruned may result in an untidy plant, which has grown into an undesirable shape that is hard to fix without drastic pruning. Sometimes it’s time to advise clients, that a massive cut back is needed. Warn them of the consequences that the shrub maybe lost, but if it survives the plant will eventually look so much better. The key is to get permission for drastic action, so you do not have to pay for replanting.
You now have the machines to prune efficiently, and with more frequent use you may just improve the quality of your landscape. Look out for tree pruning in the next issue. Happy pruning! LM.