Everyone loves to see an immaculate hedge, trimmed perfectly, with that perfect smooth, dense surface. Having the right trimmer for the job makes all the difference, and so does taking care of it properly. If you have an old trimmer, now is the right time to be out buying a new one, so that your hedge will look great and the job will go quickly. If you feel bewildered about which kind of trimmer to buy, read on, and things will soon be a lot clearer. In this part we will look at the basic parts and options of a trimmer, and safety features to look for. Next time we will look at the possible power sources for your trimmer.

Trimmer basics – the components

A power trimmer is a simple machine. It has a motor, either electric or gasoline, which drives a bar in a reciprocal action – back and forth. This slides along a fixed bar, the blade support rod. There are teeth along both the blade and the support, which create a scissor action cut at each tooth. There are several differences between trimmers that you should consider when shopping and thinking about what your personal needs and abilities are:

Single-sided or double-sided blade?

Most trimmer blades have teeth along both sides, but some have them on one side only. Single-sided blades are safer to use, because you are always cutting away from yourself. Double-sided blades are more usual and cutting in both directions is considered better for your hedge. If you are left-handed then a double-sided blade will be easier to use.

How wide is the gap between the teeth?

The space between the teeth varies, and it determines the widest branch you can cut cleanly. The branch has to fit between the teeth to be cut. Larger machines have more powerful engines, and can cut thicker branches, so the teeth are wider apart – an inch or more. If you are planning to cut an over-grown hedge, with thick branches, then you might need that, but for ordinary use a gap of 3/8 to ¾ of an inch will be fine. Remember that for most conifers (yew is an exception), if you cut into a thick branch with no green parts on it, it won’t regrow, so if you have an arborvitae hedge for example, like Thuja Green Giant, you don’t want to be cutting into thick branches anyway. Also, finer spacing gives a neater trim, so if you trim regularly, a narrow gap will give you the best results.

How long is the blade?

Blade lengths vary a lot. A short blade is useful for smaller plants, but it will take longer to do a large hedge, and it’s a little harder to get a really even surface with one, too. Longer blades are heavier, and change the balance of the trimmer, making it harder to lift up. So if you are not too strong you will find a long blade more tiring, although the job will go more quickly. Long blades are more difficult to use to make rounded or curving shapes too, but terrific for that flat hedge look.

A 13 to 16-inch blade is ideal for smaller shrubs, and small hedges, like boxwood.

A 16 to 20-inch blade is perfect for an average, medium-sized hedge and is a good ‘all-round’ size too.

A 20 to 40-inch blade is the choice for a big hedge or screen, or if you do a lot of trimming.

How fast does the blade move?

The ‘stroke rate’ is the speed at which the blade goes back and forth. High speed cutting gives you sharper, more precise trimming, but cut finer growth best. Speeds of up to 5,000 strokes per minute can be found. If you trim regularly, so you only cut fine growth, look for a high stroke rate and narrow teeth spacing – it will give you the smoothest hedge possible.

What is the blade made of?

Some blades are titanium coated. Others are made of high-carbon steel. Titanium is stronger and lighter, but not as hard, so it doesn’t stay sharp for so long. Most professionals choose high-carbon steel, as it sharpens well and holds the edge. However, carbon steel rusts, so you need to keep it clean and well-lubricated, especially over the winter period when it is being stored.

Wraparound handle?

This is a common feature, but it may be missing from cheaper models. If the front handle goes around three sides, you can turn the trimmer more effectively, making it easier to reach tricky spots.

Extension pole?

Some trimmers can be operated from a removable extension pole. This gives you more reach from the ground, and its quicker and safer to trim that way than from a ladder.

Is it part of a kit?

If you need a range of garden tools, like a string trimmer, or small saw, then a hedge trimmer that is part of a kit range will save you money overall, even if the initial investment is higher.

Safety Features

Anything sharp is a potential safety hazard, and hedge trimmers are no exception. To reduce the risk of injury there are several safety features available. You can decide which ones are most important to you and your own circumstances.

Front-handle shield?

Most trimmers have a shield fitted at the back of the blade, between the blade and the front handle. This protects that hand from being accidently caught in the blade, especially in those seconds when it is coming to a halt. It also deflects wood chips flying backwards, reducing the chance of one getting into your eyes (you should be wearing goggles anyway!)

Safety lock?

If you have children, then a safety lock is important. Even if you keep your trimmer in a locked cupboard you might have to leave it out for a few minutes unguarded. Children love tools! Some trimmers have a lock that secures the machine in the ‘off’ position, so it can’t be accidently started. You have to simultaneously hold down the lock and activate the machine to start it. You might find this action a bit tricky, so if you don’t need this feature you might choose to avoid it, although most machines for the home market will have it.

Tooth extensions?

Some blades have blunt sections coming from the teeth, so you hit those before you hit the blade. This is a useful safety feature, but it can make the blade heavier and a bit more awkward to use.

Dual operation?

The biggest danger when working with a trimmer is operating it with one hand and then cutting the other one, or your free arm. So some trimmers have dual switches, one on the handle and one on the bar that runs across the top. That way you can only operate the machine when holding it with both hands. This does reduce your potential reach, so you might need a taller ladder to trim the top, for example.

Lock on?

If you do a lot of trimming, being able to lock the blade on, rather than have to keep squeezing the handles, makes trimming easier. It does of course also make accidents more possible.