Pruning roses is something that paralyzes some gardeners. The information on how to prune roses can be overwhelming and cause you to avoid even planting roses. The reality is that pruning roses can be meticulous, but it can also be quite simple and doesn’t have to be complicated. The reality is that rose bushes are extremely tough (especially here in Southern California) and can handle even the most ignorant pruning. Paralysis by analysis is not the answer, and need not prevent you from pruning your roses out of a fear of doing it incorrectly.

General Rules

Some common rules that you’ll hear are:

• Seal Cuts
• Disinfect tools to prevent spreading disease
• Prune canes at an angle between 10-40°
• Prune dead, diseased, downward growing, and damage canes.
• Prune back to the best 3 or 5 canes

These general rules have evolved over time as scientific explanations and traditions merged to advise others. Not all of them have are necessary nor benefit the rose as advertised. Below we’ll discuss which are necessary and why they are suggested. Before that, I’d like to leave a list of all the “rules” I’d suggest incase you’re too lazy to read or don’t need to know the reason why:

Sealing Pruning Cuts

Not only is this cumbersome and time consuming, but it doesn’t effectively do what it is said to do. The reason people seal cuts is to prevent diseases and pests from causing damage to the plant. Linda Chalker-Scott from Washington State University states:

“For some inexplicable reason, some people are compelled to “manage” a process that plants have evolved
over millions of years. Every year, trees form hundreds of tiny abscission layers as leaves senesce and
fall. Wounds left from branch breakage are callused over and compartmentalized.”

“It’s important to recognize that trees do not heal. Instead, they isolate damage through formation of
suberized, lignified wood that physically and chemically repels invasion.”

Linda Chalker-Scott, Ph.D., Extension Horticulturist and Associate Professor,
Puyallup Research and Extension Center, Washington State University – https://s3.wp.wsu.edu/uploads/sites/403/2015/03/wound-sealer.pdf

You can replace the word tree with woody ornamental, which a rose would fall under.

If you search hard enough you can find research that shows that sealing cuts is effective and necessary, but it tends to relate specifically to certain plants, pests, diseases, times of the year, and environments.

Disinfecting Tools

I feel that people repeat the need to disinfect tools without any knowledge of why and when, other than “You’re supposed to do it every time you prune.” Hearing this insincere repetition with no knowledge behind it makes me rolls my eyes. However, there are definitely situations where it is necessary. If you’re in production of plants, orchards or harvesting as a significant source of income it would greatly benefit you to thoroughly understand the article below. If not, and you’re just pruning in your garden, you can generally be safe knowing the following information:

To disinfect your tools or not – what’s the bottom line? To make an informed decision, you need to know your pathogen and its life history, and use common sense:

1. If it’s a virus or viroid, disinfect your tools.
2. If it’s a vascular fungus or bacteria, and/or forms oozing cankers, disinfect your tools
3. Avoid cutting active, oozing cankers; wait until they dry.
4. If you are pruning irreplaceable plants, disinfect your tools.
5. Choose a disinfectant treatment that has been shown to be effective through published research; I would probably not use alcohol but one of the common household cleaners at full strength.

Sterilized Pruning Tools: Nuisance or Necessity? – Dr. Linda Chalker-Scott – https://s3.wp.wsu.edu/uploads/sites/403/2015/03/Pruning.pdf

In that same article Linda Chalker-Scott also mentions:

“It is probably not necessary to sterilize pruning tools to prevent transmission of soil- or air-borne pathogens. These diseases, generally bacterial or fungal in nature, are more likely to be transferred by your hands and clothing than by your pruning tools. Obviously you should avoid being a direct vector in disease transmission, but you will probably have better success in controlling these diseases through preventative landscape management practices (e.g. pruning diseased parts, disposal of contaminated leaf litter, and use of disease-free compost and mulch).”

Sterilized Pruning Tools: Nuisance or Necessity? – Dr. Linda Chalker-Scott – https://s3.wp.wsu.edu/uploads/sites/403/2015/03/Pruning.pdf

None of those common fungal diseases are viral, vascular fungus, nor form oozing cankers and therefore do not require sterilization of pruning equipment between cuts/plants. The viral diseases listed above are commonly transmitted during propagation and can be a major concern for production nurseries, but are less common in household gardening. In the case that you do run into a viral disease, you should follow the guide below to find a solution that will effectively disinfect your pruning equipment.

Linda Chalker-Scott also writes an article about which disinfectants to use: https://s3.wp.wsu.edu/uploads/sites/403/2015/03/cloroxed-clippers.pdf

Below is the link to the article cited above. This article explains disinfecting tools so much better than I ever could, and I’d suggest reading it (its only 2 pages).

Pruning Canes At An Angle

The reason pruning at an angle is suggested by many is to keep water from pooling up on the cut site, which prevents proper healing.

Personally, I find this misleading as there is nothing about an angular prune that is horticulturally superior to a straight across cut. You technically expose less area if you prune perpendicular to the growth of the cane rather than exposing more of the cambium layer. On top of that, if the cane is growing at a 40° from the ground a straight cut does the trick.

All of that said, I still agree with the aforementioned article under Sealing Pruning Cuts that plants manage cuts on their own and we need not impose additional necessities to ensure they have a perfect condition. They compartmentalize, and prevent infections themselves. When they don’t do a sufficient job, we intervene and correct that for the health and aesthetics of the plant (see section below about pruning).

Prune Dead, Damaged, Diseased, and Downward Growing Canes

The 4 D’s of pruning are always a basic guide for pruning any woody perennial. Just as you wouldn’t want any dead, damaged, or diseased canes growing on your roses, you wouldn’t want any flowering canes to be growing into the ground. These pruning cuts can be done year round to maintain the health of the rose. Damaged canes include crossing canes that rub against each other and create open wounds.

When it comes to pruning diseased canes you want to prune the cane before the disease starts to remove the entirety of the diseased cane. Also ensure to remove the diseased canes and other leaf litter to remove the chance that it infects the bush again.

Prune To The Best 3 To 5 Canes

From everything that I can find, there is no horticultural reason for pruning back to 3-5 canes. This is a commonly suggested tip while pruning, but I feel that the necessity of this tip is that you prune back to build the structure for the rose to grow outwards. This allows for air circulation through the middle of the rose which helps cut down on diseases that commonly affect the rose such as powdery mildew or anthracnose.

The following quote from Kitty Belendez destroys the idea that pruning to 3 to 5 canes on all roses is what should be done.

The rose pruning books would have you believe that every rose bush in your garden needs to be trimmed to exactly 3 or 5 canes. That is nonsense. Of course, your new bareroot roses will probably have 3 to 5 canes, but established rose bushes will have many more canes than that, and it would be horribly sad to cut off all those bloom producing canes. I keep all the newest, greenest rose canes, and this could mean 12 or more depending on the variety and the age of the rose bush. Do cut off all those very old, brown rose canes. You want to encourage new, green basal canes to grow.

Kitty Belendez – Master Rosarian, Santa Clarita, California – http://www.santaclaritarose.org/Pruning.html

When Should I Prune Roses?

I’m going to tell you something that may seem crazy. Prune them whenever it works for you. As Kitty Belendez (among other professional rosarians) mentions in the cited article, each rose is different with different needs, and different people have different things that work for them. Roses rarely die from pruning, and you learn as you prune. I have neighbors that prune their roses like 5 times a year here in Southern California, and my mother has similar rose types that she prunes one to two times a year and they both flower nicely, but they look different (not bad, but different).

Each type of rose requires different things in different environments to accomplish different goals. There is no baseline rule that can be applied like a blanket. If you just need a basic rule to go by, prune in the Fall and Spring. The exception to this are heritage roses that need to be prune after they bloom as they only bloom once in a season. They flower on last years canes, so pruning them off before they flower would keep them from ever flowering.

Resources Used:

Kitty Belendez – “Demystifying the Rose Pruning Process: What the Textbooks Don’t Tell You” – http://www.santaclaritarose.org/Pruning.html
Dr. Linda Chalker-Scott – “Sterilized Pruning Tools: Nuisance or Necessity?” – https://s3.wp.wsu.edu/uploads/sites/403/2015/03/Pruning.pdf
Dr. Linda Chalker-Scott – “The Myth of Wound Dressings: “Apply wound dressing after pruning to insure against insect or fungal invasion”” – https://s3.wp.wsu.edu/uploads/sites/403/2015/03/wound-sealer.pdf
Dr. Linda Chalker-Scott – “The Myth of Cloroxed Clippers: “A bleach solution is the best choice for disinfecting pruning wounds and tools”” – https://s3.wp.wsu.edu/uploads/sites/403/2015/03/cloroxed-clippers.pdf

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