Why Winter Is The Best Time To Cut Back Karl Foerster Grass

When you are looking for a perfect ornamental grass for your yard that you can enjoy all year round, Karl Foerster grass, also called feather reed grass, is a popular choice. This species has narrow leaves and 5-foot flower stems that change from a purplish color in spring to a sandy color in autumn. They often wave in the wind, creating an eye-catching look no matter what time of the year you see them. It is also are a deer resistant grass, which is ideal for those who don't want deer eating their lawn. However, there is one time of year that you will want to cut down this grass' height, ensuring that it grows back stronger in the spring. The best time to cut back Karl Foerster grass is late winter.

You could cut it in late autumn at the end of the growing season, but most people appreciate the height of this grass all winter long, yielding a pleasing design element in a garden when plants are usually dormant. The stalks should remain upright, even during harsh winter winds. When cutting down the stalks, aim for at least within 6 inches of the ground by late winter, so that the plants are ready to generate new growth in the early spring. Some experts recommend going even shorter, cutting the plants as close to the ground as possible rather than leaving a few inches standing, that way the green shoots have no impediment when they begin growing.

When you are cutting down the previous year's growth on your feather reed grass, you can either do the work by hand or use a power tool. The leaves and individual stalks are not too difficult to cut by hand with pruners, or with a scythe or sickle. You could purchase a hand-held sickle at Home Depot for less than $25, while a pair of hand pruning shears will cost less than $15.

However, because they grow in clumps, which can carry a significant thickness and density, using a power tool is always going to be more convenient and efficient. Try a power hedge trimmer or a string trimmer. You can purchase a cordless electric hedge trimmer for less than $65 on Amazon. If the clumps are especially dense, some people may even use a chainsaw. If using power tools, you should always wear eye protection just in case some parts of the grass fly upward into your face. Gloves with a good grip are also a good idea, so the tools do not slip out of your hands, especially in the cold weather.

Because the base of the Karl Foerster grass can reach up to 2 feet in diameter, cutting through all of it can be a bit of a challenge. Some people may struggle to cut the plants as close to the ground as possible, because they have difficulty bending over that low or sitting on the cold winter ground. If so, there's nothing wrong with cutting it as high as 6 inches from the ground, where it may be easier to work. 

If you're worried about trimming it too close to the ground, it's worth noting that there's no chance the previous year's growth, which has already turned brown, will resume growing, so you'll be relying solely on new growth from the soil. If you leave any height of old growth in place, it may take away from the pleasing look of this plant's early new shoots, though this a personal preference.

If you want to simplify the process, use a bungee cord and wrap it around the full diameter of the clump a few inches above where you want to cut. This holds all the stalks and leaves tightly together, making it far easier for you to see where you are cutting, while also creating more tension. After wrapping it, just begin making your cuts. With pruners, work in sections, slicing several stalks simultaneously. With a power tool, you can just start on one side and work through the entire clump in one go.