Now that high-tech shears and clippers are available, gardeners don't use pruning knives as much as they once did. But these hook-shaped implements -- which resemble carpet knives -- are useful when delicacy is required. With a sharp pruning knife, you can easily cut thin stems up to 1/2 inch in diameter and clean up the bark on thicker stems that you've lopped with shears. It's important to keep your pruning knife sharp, clean and safely folded away when you aren't using it.
Pruning a Vine
You might reach for a pruning knife when detailing a hanging vine -- for example, English Ivy (Hedera helix), which is hardy in U.S. Department of Agriculture plant hardiness zones 4 through 9. This common wall cover is vigorous and needs assiduous control to prevent it from quickly covering windows and doors; in fact, it's vigorous enough to take over from native species in the Pacific Northwest, where it's considered invasive.
Use the pruning knife to cut back unwanted growth in a vine such as this by holding a leaf away from you, putting tension on the stem and cutting with a sharp slicing motion away from your body. Keep the plant healthy by cutting stems at least 1/2 inch away from the branch from which they're growing.
Cleaning Up Saw or Lopper Cuts
When you lop or saw larger woody branches, small pieces of bark are often left hanging, and a pruning knife is a good tool for cleaning these up. Holding the knife with the blade almost parallel to the stem, and slice the ragged pieces off the stem with a quick motion away from your body. Allow your hand to lead the knife and let the hooked part of the blade do the work. Don't use a cutting motion -- a single swipe of the hand is best.
Caring for Your Knife
A few basic procedures keep your knife ready for the delicate work it's intended for, while protecting your plants from disease:
- Sterilize your knife with 70, 90 or 91 percent rubbing alcohol when you're done with it for the day. You can also use full-strength alcohol-based mouthwash, but avoid bleach, which corrodes metal. If you're doing a lot of trimming or cutting several plants, sterilize the blade between cuts as well.
- Rub mineral oil on the blade, and fold the blade into its holder when you put the knife away. If your knife isn't foldable, store it in the case in which it came.
- Sharpen the blade periodically on a whetstone. Immerse the whetstone in water for 10 minutes and keep it lubricated with water while sharpening. Keep the blade at a 10- to 15-degree angle with respect to the stone, and draw it away from your body. Move the handle toward the stone as you draw to ensure the inside of the hook gets sharpened.