I think the complete question should read like: What tools to use to trim Buxus topiary shrubs … in a Japanese- and more specifically Zen-garden?
Throughout the years I have used, or perhaps it is better to say tested or tried to use, a number of different tools to trim the topiary Buxus (Box) in our garden. At the end I am always using an ordinary hedge-shears complimented by an also ordinary pruning shears.
A disadvantage of using a hedge-shears (top most under the small pruning shears) is that it requires labour and clean-up afterwards. I use a self-sharpening model, and that is what it does. Frequent cleaning is all it needs. It can cut rather thick twigs and results in a clean cut that in most cases does not require a whole or partial redo.
The pruning shears is used for the fine-tuning to remove any twigs that where left. When finished I shake the shrubs-surface with the flat hand, the top as well as the sides, so as to remove left leafs and twigs. This can also give room to longer twigs that pop out. At the very bottom of the shrub there will also be some twigs that escaped the hedge shears. Sometimes we have some edges and corners that are difficult or risky to clip with the hedge-shears. For al these I also use the pruning shears.
Electric hedge trimmers are available in different models, based on different techniques. On the photo you see three of these. Top to bottom (under the hedge-shears) a mains-power operated electric hedge-shears, a battery operated electric Box- or Buxus-shears, and an also mains-power operated electric hover-like (garden Groom) collecting hedge trimmer.
I have always been extremely reluctant to use powered tools in our Zen-garden. It just does not seem to fit and does not make sense to use them. But then topiary are getting mature (larger) and I am not getting younger. Getting the right shape involves labour but also a form of artwork. After the shape has become mature the artwork part gets less and it more and more becomes hard labour to keep them in the right shape and size. At different intervals I am advised to use mechanised tools and sometimes a have followed such well meant advices.
Mains-power operated electric hedge-shears
The mains-power operated electric hedge-shears (orange center-left) is an old one. It is not really suited for clipping the flexible and soft Box-twigs. Meaning that you have to redo the surface a couple of times. Then you also have the hassle of the mains-cord and it is very noisy. Added up: forget it.
I am sure there are more suited devices on the marked so I will have a closer look in the near future.
UPDATE: In July 2012 I bought a new mains-power hedge shears ! Although the cable indeed is a bit of a hassle and something to be extremely aware of, it already saved me days. It took me over 13 years to get to this stage, because this device just does (still) not fit in a Zen-garden. However the time I gain is substantial and most of the time is now consumed by the preparations and tidy-up.
The noise of this new device is far less than that produced by my old one and this also cuts far better and sharp. So the ‘.. to redo the surface a couple of times’ does no longer apply and even most rounded shapes can be trimmed very nicely. This shears does leave more marks than the hand shears but it all is very acceptable and will have disappeared in a few weeks time.
Specialised battery operated electric Box- or Buxus-shears
The battery Buxus-shears (blue-black at the center) gave up after 5 years of modest usage. I guess end of life of the rechargeable battery. It still runs but slowly without much power. The battery-pack can be replaced so I now need to find out if i can order one (and the cost involved. Unfortunately the battery is not interchangeable, meaning that it only lasts for about one hour and then needs a recharge. The full re-charge takes a couple of hours.
It gives a clean cut but you always have to redo a clipped surface because it just won’t cut all twigs in one go. Meaning that the cut gets less clean and it takes even more time then using the hedge-shears. It requires less labour though. After a job well done it also requires clean-up.
Because of the fact that it only operated for an hour I can not use it for most of the topiary but only use it in place that are difficult to reach where I can use it with one hand.
The mains-power operated electric hover-like (Garden Groom) collecting hedge trimmer
The electric collecting hedge trimmer (green white bottom-right quadrant) is not suited for the Buxus in our garden. Why is that?
Saves time – Eliminates clean up … However the built-in container is so small that it takes almost more time to empty it far to often then it takes to clean up. May be great for a smaller garden. While the debris-container fills up it gets more and more weight making it heavy to work “overhead”.
Shredding action reduces waste 10:1 … May very well be true. Nonetheless it fills up very quickly (see previous unique selling point).
Ideal for trimming & shaping … This all depends on the shapes. In our case it is very tricky to use because you can only see what you did after you have done it. Also it can not be used for inside-corners and small shapes and details. For large flat or close to flat surfaces it does just fine. That is to say on other then Box shrubs, perhaps hedge rows. Buxus leafs and twigs get literately ripped apart and show frayed. The device is very noisy and you also have the hassle of the mains-cord.