The science behind pruning - Part 1

Gardening is both art and science combined but I always try to approach gardening as science first. It gives me comfort that I would be able to understand a great deal about plants to respect their habits, growth and needs. Arts I believe will come in knocking, invited, naturally.




In the same way, I like to understand pruning scientifically since this helps me with my judgement - know what to cut and when to stop whenever I hold the pruner and go cut cut cut..

Science no. 1: Roses are plants that bloom constantly on any NEW vegetative growth

Pruning forces or fools roses to produce new growths. 

When roses lose their parts to pruning, they quickly replace what's lost by producing many new growths for survival reason. 

Since for roses, flowers always come at the end of any new growths, many new growths equate to many flowers. This is what rose growers always want at the end of the day – more flowers. 

For this reason alone, rose growers believe in pruning and exercise it religiously.

Science No. 2: New growths always come from a mature branch or stem

New growths often come from matured canes or already spent flowering stems. New growth emerges from a tiny little node or a swollen area (termed as a bud eye) you can find near the base of a leaflet.

New growths tend to be a lot smaller or shorter compared to branches/stems where they grow from. This is because the more extensions (growths) a rose has, the thinner its energy is spread across.

Spindly growths or smaller stems produce smaller flowers. By cutting back stems (aka pruning) to where they are bigger, new growths will be much stronger resulting in larger blooms.

Personally, I don't find this concept entirely true for certain rose cultivars. I have seen countless times in my garden that new growths from much smaller stems can produce equally big flowers. At times, the new stems produced are equally as big and long as the stems where they grow from. Kind of telling me that they are not 'a new growth' after all but an extension to what was cut off. 

I believe that when optimum care such as enough water, light and nutrients are provided, energy is what the tree generously give itself and make plenty of it to spread across.

Not all growths come from mature woods, some can come from the base of the plants or from the ground. These growths are termed as 'basal breaks'. These are the best growths any growers could ever wished for as they promise for an entirely new plant body (not just some arms and fingers as in branches and stems). You can guess what a new body can do, can't you?

Science No. 3: The key to healthy roses are enough light and good air circulation

Pruning is to open up the center of the plants for better light penetration. When a rose loses some of its top leaves, there is enough light shines through for the lower leaves. Rose gets optimum photosynthesis this way. 

The bush is also drier on wet days as pruning can open up the bush to aid with air circulation, which in turn preventing diseases such as black spot.

I could not stress enough on how light plays a major role in ensuring a healthy bush. But I cannot help but stand contradicting on this particular practice.

I see that opening the center of the plant for light to shine through seems a bit redundant when we actually growing roses... well, in the equator! 

Here, light comes from all angles -  left, right and straight from the top. The light is at least of the same quality and quantity throughout the year. Photosynthesis, if not 6/7 is 12/7 all year long depending on the location where you put your roses. With warm air starts breezing from 11am till sundown, the bush can get dry on its own pretty quickly.

And you know what? Less leaves less photosynthesis.

When it comes to better air circulation, there's also a question of how big or wide our rose bush really is?

It is understandable that monster bushes like what we see mostly in western countries of temperate climate do require some pruning to control the gigantic growth, but our rose bushes ever hardly reach 3-4 ft wide in containers and probably spread less than 4-5 ft across for roses on the ground. Having this hot weather, we are slightly unfortunate as our roses do take time to grow and get bushier. 

Blackspot in my garden is quite seasonal. As the monsoons come, the blackspot arrives. I keep my roses as they are but work on preventing blackspot through a better garden care. To me blackspot comes and goes easily as the season changes that I should not be put off or worry too much about it, as it does tolerable damage. 

Snipping of the top growth lightly may do just fine but I am more at this point on the belief that my roses are better off wearing every single leaves they have, to make food and to survive. I also believe that leaves keep them cool. So, I am  keeping most of their foliages on no matter rain or shine!

Join me soon for Part 2.

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