Ornamental Grass Care: Watering, Pruning, Dividing & More

Ornamental Grass Care: A Complete Guide

Ornamental grasses add texture, movement, and year-round interest to gardens and landscapes. With their graceful forms and low maintenance needs, they are a favorite among homeowners and gardeners alike. However, to keep ornamental grasses looking their best, proper care is essential. This guide covers everything you need to know about watering, fertilizing, pruning, dividing, and preventing pests and diseases in ornamental grasses.

Watering Ornamental Grasses

Proper watering is crucial for establishing healthy ornamental grasses, especially during their first year. Here’s how to water ornamental grasses for optimal growth:

• When first planted, water ornamental grasses every other day for the first few weeks to help establish their root systems.
• After the initial few weeks, reduce watering to twice a week for the remainder of the first growing season.
• Once established (after the first year), most ornamental grasses can thrive on natural rainfall alone.
• During prolonged dry spells, provide supplemental water every three weeks to prevent stress.
• Mulch around the base of new plants to help retain moisture and reduce the need for frequent watering.

Some ornamental grasses, such as annual and perennial Pennisetum varieties, are not drought-tolerant and require average moisture. Avoid letting the soil dry out completely, but also avoid soggy conditions. If the tips of the leaves turn brown, it’s a sign the soil is too dry.

Fertilizing Ornamental Grasses

Ornamental grasses generally have modest fertilizer requirements. Over-fertilizing can lead to weak growth and increased susceptibility to diseases. Follow these tips for fertilizing ornamental grasses:

• Most ornamental grasses do not need additional fertilizer, especially fine and hard fescues or purple fountain grasses.
• For other types, apply a slow-release fertilizer in the spring.
• A mixture of rotted manure, mushroom compost, and leaf mold can provide essential nutrients without over-fertilizing.
• Be cautious not to over-apply fertilizer—excessive nutrients can cause weak growth and increase disease susceptibility.

Native prairie or woodland grasses thrive in poor soils and receive nutrients from decomposing organic material. Adding bark or leaf mulch around the base of your grasses can mimic these natural conditions.

Pruning Ornamental Grasses

Pruning ornamental grasses is an important part of their annual maintenance. Proper pruning encourages healthy new growth and keeps your grasses looking tidy. Here’s how to prune ornamental grasses:

• Wait until late winter or early spring, just before new growth begins.
• Use sharp, clean pruning shears or hedge trimmers.
• Cut the grass back to about 4–6 inches above ground level.
• Remove all cut foliage and dispose of it in your compost or yard waste.
• Rake the area around the grass to remove any remaining debris.

For smaller grasses, pruning shears are usually sufficient. For taller grasses with thicker stalks, you may need electric hedge trimmers or even a chainsaw. Always wear gloves and long sleeves when handling ornamental grasses, as their foliage can be sharp.

Herbaceous grasses should be left standing over winter to protect the crowns of the plants and provide food and shelter for wildlife. Evergreen grasses benefit from an occasional “combing” or light raking to remove dead leaves and keep them fresh and tidy.

Dividing Ornamental Grasses

Dividing ornamental grasses every three to four years prevents overcrowding and promotes healthier, more vigorous growth. Here’s how to divide ornamental grasses:

• Cut back the grass as described in the pruning section.
• Use a sharp spade or ax to divide the root ball into smaller sections.
• Carefully dig out one or more sections, leaving at least one part in the original location.
• Replant the divided sections in prepared soil, water thoroughly, and maintain as you would a new planting.

For smaller grasses, you can use your hands, pruning shears, a knife, or a sharp shovel or trowel to cut or pull the clump into several pieces. Make sure each piece has some healthy roots. For larger grasses, you may need to use an axe or chain saw to divide the root ball.

Divide warm-season grasses anytime from spring through mid-summer. All ornamental grasses should be divided when they are actively growing but not while they are flowering. If the plants are dormant when transplanted, they won’t establish a good root system.

Preventive Measures for Healthy Ornamental Grasses

Preventive care is key to keeping ornamental grasses healthy and resistant to pests and diseases. Follow these tips:

• Apply a layer of organic mulch around the base of the plants to retain moisture and suppress weeds.
• Maintain good air circulation by spacing plants appropriately.
• Plant grasses in appropriate locations with proper sunlight and soil conditions.
• Remove dead or diseased foliage promptly.
• Water at the base of the plant rather than from overhead to reduce the risk of fungal diseases.

Common Questions About Ornamental Grass Care

When is the best time to prune ornamental grasses?

The best time to prune ornamental grasses is in late winter or early spring, just before new growth begins.

How often should I divide ornamental grasses?

Divide ornamental grasses every three to four years to prevent overcrowding and promote healthy growth.

Do ornamental grasses need fertilizer?

Most ornamental grasses do not need additional fertilizer. A light application of slow-release fertilizer in the spring can be beneficial for some varieties.

How do I know if my ornamental grasses need water?

If the tips of the leaves turn brown, it’s a sign the soil is too dry. Water your grasses thoroughly during dry spells.

Can I leave ornamental grasses standing over winter?

Yes, herbaceous grasses should be left standing over winter to protect the crowns and provide food and shelter for wildlife.

Summary Table: Ornamental Grass Care Checklist

Conclusion

Ornamental grasses are a beautiful and low-maintenance addition to any garden. By following these care tips for watering, fertilizing, pruning, dividing, and preventive maintenance, you can enjoy healthy, vibrant grasses year after year. Whether you’re a beginner or an experienced gardener, ornamental grasses are sure to enhance your landscape with their graceful forms and year-round interest.