Help with pruning of balcony plants Thuja Occidentalis AKA Smaragd.
ChangeAgent
Posts: 6
Reminder, you are talking to an absolute beginner, never tried anything like it to grow on my balcony.
I have the following Thuja Occidentalis on my balcony, well two, in a pot. See pics. They have been doing very well and now the point has come to prune a bit here and there. My main worry is to stop them from getting any taller or wider, and how to prune it or shape it. See I want to keep the cone shape of the plant, having it get not any wider and make sure it still looks natural and, in a cone-shape. And maybe there is a time of year that is better than others. I assume spring or autumn.
Both, one more than the other, have sort of several tops, does anybody know if I could bring those more into a cone shape by putting on some training wires that pull them together a bit like with a bonsai as it is trained? For this I would use old strips of inner bicycle tubing. I do this also with an indoor Ficus I have since 25 years which is ±2.6 Meter high and ±1.20 Meter wide. What would be the best method according to your knowledge? Or does anybody have any other ideas?
So dear experts out there, how to do this? Love to hear your tips and ideas.
Posts
Most conifers need trimmed regularly - ie each year, sometimes twice, by just a small amount, to avoid cutting back into old wood, as they often don't recover from that. The best way to keep the shape is to do that.
Thujas are more forgiving, but it's always better to only take off the previous year's growth each time to avoid damage.
It sounds odd that you say they have more than one leader though. Have they had the tops taken out at some point? Smaragd usually has quite a defined shape, which is why they're popular, as they don't require much shaping to keep them neat.
I live in west central Scotland - not where that photo is...
and not sure why the computer needs to turn them or how to correct this.
I'm not sure how successfully you could pull the tops in, but normally, those would all keep growing and would just keep the general cone shape, with the slightly shorter stems staying shorter than the main leader, if that makes sense.
As you're wanting to keep them smaller than their ultimate size would be, you could probably experiment a little with some wire or string, just to see how they do. Not something I've ever tried, but I can't see the harm.
They're looking very well anyway.
I live in west central Scotland - not where that photo is...
So how should I go about it?
There was a good tip on trimming conifer cones and obelisks to a sharp point with even sides on a recent Carol Klein/Channel 5 programme on Woollerton Old Hall gardens recently. They made a simple ‘batter guide’. An L shaped construction of two wooden lengths, braced at the bottom, with the vertical length at a wider angle to rest against the outer edge of conifer. Presumably they moved it around, trimming the excess that poked out. You could do something similar, with the top of the angled upright going a little higher than the current height. If you regularly trimmed the new top growth around all sides it should eventually grow to meet as a point. A wigwam of bamboo canes with horizontal crossbars at the base to maintain the correct angle and distance of canes, popped over each conifer at trimming time would also work as an accurate guide.