Essential Tips for Cutting Back Ornamental Grasses

How and When to Cut Back Ornamental Grasses: A Complete Guide

Ornamental grasses add texture, movement, and color to gardens throughout the year, bringing beauty and versatility to landscapes of all types. Known for their ease of care, these grasses require minimal upkeep compared to many other plants. However, a key part of maintaining healthy and vibrant ornamental grasses is knowing how and when to cut them back. Cutting back ornamental grasses at the right time helps promote fresh growth, enhances the plant’s structure, and keeps your garden looking its best.

In this guide, we’ll cover everything you need to know about cutting back ornamental grasses, including tips on timing, techniques for trimming different types of grasses, and pro tips to help you achieve the best results. We’ll also answer common seasonal questions to provide a comprehensive look at ornamental grass maintenance.

Why Cutting Back Ornamental Grasses is Important

Cutting back ornamental grasses is essential for several reasons:

• Encourages New Growth: Trimming dead foliage allows new shoots to emerge, creating a lush and full appearance for the growing season.
• Improves Plant Health: Removing old, dead blades reduces the chances of disease and pest issues, helping your grasses remain strong and healthy.
• Maintains Appearance: Overgrown, untidy grasses can detract from a garden’s aesthetics. Cutting them back helps maintain their shape and ensures they stay attractive year-round.
• Prepares for Seasonal Changes: Trimming back ornamental grasses in the correct season prepares them for either dormancy or active growth, depending on the time of year.

When to Cut Back Ornamental Grasses

The timing of cutting back ornamental grasses depends on the type of grass you have. Ornamental grasses are generally divided into two main types: cool-season grasses and warm-season grasses. Understanding the growth cycle of each type will help you know when and how to trim them.

Cool-Season Grasses

Cool-season ornamental grasses grow actively during the cooler months of early spring and fall. They typically begin growing as soon as temperatures warm up slightly in late winter or early spring. Because these grasses start growing earlier in the year, it’s important to trim them back before new growth begins.

• Best Time to Cut Back: Late winter to early spring, before new growth emerges.
• Examples of Cool-Season Grasses: Feather Reed Grass (Calamagrostis), Blue Fescue (Festuca glauca), and Tufted Hair Grass (Deschampsia cespitosa).

Warm-Season Grasses

Warm-season ornamental grasses start growing in late spring or early summer when temperatures rise. These grasses go dormant in the winter, which makes late winter or early spring an ideal time for trimming.

• Best Time to Cut Back: Late winter to early spring, after the risk of frost has passed.
• Examples of Warm-Season Grasses: Maiden Grass (Miscanthus) and Fountain Grass (Pennisetum).

Pro Tip: For a quick visual guide, if you’re unsure whether your grass is cool- or warm-season, observe its growth patterns. Cool-season grasses stay green and continue growing in mild winters, while warm-season grasses typically go brown and enter dormancy in the winter.

How to Cut Back Ornamental Grasses: Step-by-Step Guide

Cutting back ornamental grasses is relatively straightforward, but using the right techniques can make the process easier and yield better results.

Step 1: Gather Your Tools

The tools you need depend on the size of the grass and how dense it is. Here’s what you’ll need:

• Hand Pruners: For small, clump-forming grasses.
• Hedge Shears: For larger grasses or dense clumps.
• Electric Hedge Trimmers: Useful for large or extensive ornamental grass plantings.
• Twine or String: To bundle grasses for easier cutting and cleanup.
• Protective Gear: Wear gloves, long sleeves, and eye protection to avoid cuts from the sharp edges of grass blades.

Step 2: Prepare the Grass

For larger grasses, wrap the clump in twine or string about one-third from the top. Bundling makes the trimming process easier and minimizes cleanup, as the cut grass stays contained in the bundle.

Pro Tip: If you’re dealing with tall grasses, such as maiden grass or pampas grass, tying them before cutting reduces the chance of pieces scattering, making cleanup much simpler.

Step 3: Determine the Cutting Height

When cutting back ornamental grasses, it’s essential to avoid cutting too close to the ground. Generally, cut back the grass to about 4 to 6 inches above the ground. This height protects the crown of the plant, which is where new growth will emerge.

• Cool-Season Grasses: Trim to 4-6 inches to give enough room for new growth.
• Warm-Season Grasses: These can typically be trimmed down to 4-12 inches, depending on the variety.

Step 4: Trim the Grass

Using your chosen tool, cut through the bundled grass at your designated height. Try to make clean cuts to avoid tearing or damaging the plant. Once you’ve completed the cuts, gather up the bundle and dispose of the clippings.

Additional Tips for Cutting Back Ornamental Grasses

• Don’t Cut Too Early: Cutting back warm-season grasses in the fall can expose the plant to cold and stress. Wait until late winter or early spring.
• Leave Grasses for Winter Interest: Some gardeners choose to leave grasses standing through the winter as they add texture and interest to the winter landscape.
• Dispose of Clippings Properly: Some grasses can self-seed, so it’s best to dispose of the clippings instead of composting them, especially if you want to prevent spreading.

Pro Tips for Specific Varieties

Each ornamental grass has its own characteristics, and knowing specific tips can help you get the best results from your trimming.

Mendocino Reed Grass (Calamagrostis)

• Best Time to Trim: Late winter, as it’s a cool-season grass.
• Cutting Height: Trim to about 4-6 inches from the ground.
• Pro Tip: This grass stays upright throughout the winter, so consider keeping it until late February to add structure to your winter garden.

Maiden Grass (Miscanthus)

• Best Time to Trim: Early spring, after dormancy.
• Cutting Height: Cut down to 6-12 inches from the base.
• Pro Tip: Wear gloves and protective gear, as the blades of maiden grass can be sharp.

Blue Fescue (Festuca glauca)

• Best Time to Trim: Late winter or early spring.
• Cutting Height: Trim down to about 3-4 inches.
• Pro Tip: Blue Fescue is prone to dieback in the center over time. Dividing the plant every few years can help it stay healthy and full.

Here are answers to common questions about cutting back ornamental grasses.

Q: Can I cut back ornamental grasses in the fall?

A: While it’s possible to cut back ornamental grasses in the fall, particularly cool-season varieties, it’s often best to wait until late winter or early spring. Leaving the grasses intact during winter provides protection for the plant’s crown.

Q: How do I know if I cut my grass back too low?

A: If you cut ornamental grasses too close to the ground, you may damage the crown, which can hinder new growth. Always leave at least 4-6 inches above ground. If you’re unsure, err on the side of caution and leave a little extra height.

Q: What should I do with ornamental grass clippings?

A: Ornamental grass clippings can be added to compost, but be cautious with grasses that self-seed easily. Alternatively, dispose of the clippings in green waste or mulch them for another area in your garden.

Q: Can I divide ornamental grasses while cutting them back?

A: Yes, late winter or early spring is an ideal time to divide ornamental grasses. Dig up the root ball, separate it into sections, and replant the divisions. Dividing rejuvenates older plants and encourages fresh growth.

Q: What if my ornamental grass isn’t growing back after trimming?

A: If your ornamental grass isn’t showing new growth, consider whether you might have cut it too low or too early. Make sure the plant is receiving adequate water, sunlight, and nutrients. Some warm-season grasses take longer to show signs of new growth, so patience may be needed.

Q: Are there grasses that don’t need cutting back?

A: Some low-growing or clumping grasses, such as sedges and certain carex varieties, don’t require regular cutting. Instead, simply remove dead or damaged blades by hand. Check the specific needs of each variety before trimming.

Conclusion

Ornamental grasses add lasting beauty to gardens and landscapes, but cutting them back at the right time and with the right technique is essential for their long-term health and appeal. Whether you have cool-season or warm-season grasses, this guide provides everything you need to ensure your grasses remain vibrant, healthy, and well-maintained. By following these tips and understanding each grass’s growth cycle, you can enjoy a lush, textured garden that thrives from season to season.