When is the best time for pruning roses in Perth?
The ideal time is the middle of winter when the rose has stopped flowering and lost its foliage. This advice has exceptions. The double white flowering floribunda rose Iceberg is so vigorous that it keeps flowering and holding on to its foliage almost through to spring. So if I said to prune your roses in July or early August then you have a date you can write into your calendar. And yes it is the perfect time to prune your Iceberg roses too.
What tools do you need for the job?
First up personal protection is more than just a good idea. I wear leather and fabric gloves, eye protection solid boots as well as a long sleeved shirt and long trousers. I generally use a battery powered hedge trimmer to get rid of bulk lots of rose stems. You can use regular hand operated hedge shears as well. I have found that most hand type hedge shears don't work too well as they need some form of gearing to make them efficient and reduce the strain on the operator. This is one reason I tend to go for Fiskars shears, these are world-class cutters with finger like gears that magnify the force from your arms and deliver powerful cutting action at the business end of the tool where the blades contact the stems.
Just for fun I have also used a chain saw for the same initial bulk cutting and it works very well. In the video we made I did use the chain saw for removing old scaly thick growth at the base of the rose as it was awkward to get to with a simple hand saw. Short handled loppers are very handy for pruning stems that are thick enough to make secateurs a bit of a challenge. Secateurs however are terrific for thin stems and cleaning up after the more aggressive mechanical hedge shears.
Some folks use an after pruning; spray-on wound dressing, which are usually based on a black bituminous compound. These are basically a waste of time and money in my opinion as Mother Nature does an excellent job of sealing off cuts.My rose pruning formula.The formula sounds appropriately simple - half by a half - by a pencil.
Step one - pick the halfway point between the top of the tallest stem and the ground. As brutally as you like cut through all the stems at this middle height. You can use a chain saw or a mechanical hedge cutter; I usually start out with a pair of hedge shears.
Step two - remove right back to the base, half of the remaining canes or stems. Here you are aiming to get rid of old unproductive stems and leave the green new stems. You will need to look hard at the stems before pruning. Old stems are often thick and have grey bark and this can sometimes be cracked and a bit flaky.
Step three - if any stems remaining are skinnier than a pencil cut these off as well. A quick calculation shows that you will remove at least 75% of the growth in this operation.
There once was an old wives tale about making 45 degree sloping cuts above outward facing buds basically that is a load of balderdash so don't even try to decipher that one. Now if you did take up my suggestion of using a chain saw you will need to go back with a sharp pair of secateurs and trim any messy cuts as these can be a magnet for disease spores to enter the plant and we don't want that.
We do have a few viruses in rose bushes in WA so there is a precaution you can take here and that is to wash the secateurs blades under running water between rose bushes to stop the spread from one plant to another.
Pruning other types of roses
Standard roses are basically regular bush roses grafted onto a tall stem so they resemble a small tree. The so-called bud union is a swollen clump of base stems and this is the source of new shoots every season. In ordinary rose bushes you find this bud union at or slightly above the soil. In a standard rose it is at the top of the stem or trunk. If you regard the bud union as the base of the rose then my half by a half by a pencil can still be used. Work out a half waypoint between the bud union and the top of the bush and make the cut. Then proceed as per my suggestion above.
If you are contemplating cutting the main trunk of a standard rose then please stop and re read the instructions as you have missed a vital part of the story.
How to prune climbing roses
Climbing roses produce very long stems often 3 to 4 metres in length and if these are allowed to grow vertically tend to yield few flowers. The major winter pruning can be done once again in July. The goal is similar to the bush pruning as detailed above where we look to clear out old grey scaly stems and leave the young smooth bark green branches. The critical job with climbing roses is to tie down the stems to the horizontal and after pruning is the easiest time to do this. Once growth begins in spring it's the side shoots from these horizontal stems that provide you with most of the flower.
Old world and many heritage roses that flower once a year in early summer need special treatment. If these are pruned in winter you risk cutting off most of the flowering wood. With these varieties wait till the October or November flower storm is over, and then go to work with your secateurs using the same formula as explained with bush roses.