Tall, narrow ornamental grasses add height, movement, and a soft screen without taking up much ground space. They work well beside fences, along paths, in small borders, and in large containers. To choose successfully, match the grass to your climate, sunlight, soil, and available width; some varieties stay upright, while others spread or flop as they mature. Before planting, check the plant label for mature height, width, hardiness, and whether the grass is clumping or spreading.
What You’ll Need
- A sunny or partly shaded site with enough room for the plant’s mature spread.
- A spade or garden fork, hand trowel, and sturdy gloves.
- A hose or watering can, plus mulch such as shredded bark or compost.
- A tape measure and plant label, if you are spacing several grasses.
- A suitable grass, such as upright feather reed grass (Calamagrostis × acutiflora ‘Karl Foerster’) for a narrow, vertical form, or a locally appropriate alternative.
Step-by-Step
- Measure the space and define “narrow.” Measure the planting strip’s width and note nearby paths, walls, windows, and utility access. Use the grass’s mature width, not the size of the nursery pot, to decide whether it fits. A tight space may suit one narrow clump better than a row of plants that will crowd each other. Keep foliage and flower stems clear of walkways and avoid blocking sightlines at driveways or corners.
- Check your growing conditions. Record how many hours of direct sun the site receives and whether the soil stays wet, dries quickly, or is compacted. Most tall, upright ornamental grasses flower and hold their shape best in full sun, commonly six or more hours daily. Shade-tolerant choices exist, but may grow less upright or flower less. Match the plant’s hardiness to your local winter conditions, and check whether it is considered invasive in your area.
- Choose a grass with a genuinely narrow mature habit. Read the full botanical name and mature dimensions on the label or a reliable local nursery listing. Feather reed grass cultivars are popular for their vertical habit; ‘Karl Foerster’ often reaches several feet tall and around two feet wide, though size varies with conditions. Other grasses marketed as tall may arch widely, spread by runners, or become broad at the base. For containers, choose a variety whose mature size suits the pot and your winter climate.
- Plant at the right time. In most regions, plant in spring after the ground is workable and severe frost has passed, giving roots time to establish before winter. Early fall can also work where there is enough time before hard freezes. Avoid planting into frozen ground or during extreme heat. Water the nursery plant before removing it from its pot so the root ball is evenly moist.
- Prepare the soil without over-amending it. Remove weeds and loosen the soil across an area wider than the root ball. Dig a hole as deep as the root ball and roughly twice as wide. Break up compacted soil, but do not make the hole much deeper or create a pocket of rich compost in otherwise poor soil. Most ornamental grasses prefer freely draining ground; improve drainage across the planting area if water regularly stands there.
- Set the plant at the correct level. Slide the grass from its pot and gently loosen circling roots. Place it so the top of the root ball is level with the surrounding soil. Backfill with the excavated soil, firming lightly to remove large air gaps without packing it hard. Planting too deep can encourage rot, while a raised root ball may dry out quickly.
- Water and mulch. Water thoroughly after planting to settle soil around the roots. Add a thin layer of mulch, about 2 inches deep, leaving a small clear space around the crown where the stems emerge. Keep the root zone evenly moist while the grass establishes, checking the soil rather than watering to a fixed schedule. Once established, many types need less frequent watering, but newly planted grasses and container plants dry out faster.
- Maintain its upright shape. Do not cut the foliage back immediately after planting. Let the plant establish and watch how it performs through a growing season. In late winter or early spring, before new growth appears, cut most deciduous grasses back to several inches above the ground. Wear gloves and use clean, sharp shears; foliage can have sharp edges. Leave evergreen grasses largely intact, removing only dead or damaged blades. Divide a crowded clump in spring if it loses vigor or outgrows its space.
Common Mistakes
- Choosing by height alone: A tall grass may spread broadly or arch over a path. Confirm mature width and growth habit before buying.
- Planting too close together: Small nursery plants can look sparse at first, but close spacing leads to crowding, poor airflow, and a messy outline. Follow mature-width guidance and allow room to divide or maintain the clump.
- Overwatering established plants: Constantly soggy soil can damage roots. Water deeply when needed, then let the surface soil begin to dry if the species prefers well-drained conditions.
- Cutting everything back in fall: Dry foliage can protect the crown over winter and provide habitat. Leave deciduous grasses standing until late winter or early spring unless local fire or safety guidance calls for earlier removal.
- Ignoring spread or reseeding: Some grasses spread by rhizomes or self-seed readily. Check local invasive-plant guidance, and remove unwanted seedlings before they establish.
Tips
- Repeat one upright cultivar in an odd-numbered group for a more natural screen, spacing plants according to their mature width rather than an arbitrary distance.
- Use a tall grass as a vertical accent, then keep lower plants around its base from hiding the crown or obstructing access for spring pruning.
- For a small garden, a single well-placed clump can create height without the visual weight of a hedge. Take a photo from the main viewing angle before planting to check proportions.
- In windy sites, choose a cultivar known for stiff stems and avoid overfeeding with nitrogen, which can produce weak, floppy growth.
- For pots, use a container with drainage holes and a free-draining potting mix. Large grasses may need a heavy pot to prevent tipping and more frequent watering during hot weather.
Troubleshooting
The grass flops or splits open: Check whether it is receiving enough sun, getting excess fertilizer, or growing in soil that stays too wet. A naturally arching variety may simply be too wide for the site; support can help temporarily, but replacing it with a tighter cultivar is often the better long-term fix. Divide an overcrowded clump in spring.
Leaves turn brown at the tips: Check soil moisture and drainage, especially during heat or after planting. Water deeply if the root zone is dry, but improve drainage or reduce watering if it is saturated. Brown tips can also be normal winter damage; wait for new growth before deciding what to remove.
The plant does not grow much in its first season: Root establishment often comes before substantial top growth. Keep weeds away, water during dry spells, and avoid heavy feeding. If growth remains poor, check that the crown is not buried and that the site meets the plant’s sun and drainage needs.
The center dies or the clump becomes congested: Many clumping grasses need occasional division. In spring, lift the plant, cut healthy outer sections from the old center, and replant divisions promptly at the same depth. Discard dead or diseased material.
Frequently Asked Questions
Which ornamental grass is tall and narrow?
Upright feather reed grass, particularly ‘Karl Foerster’, is a widely used choice. Check the mature dimensions of the specific cultivar and confirm it suits your local climate.
Can tall ornamental grasses grow in partial shade?
Some can, but many upright flowering varieties perform best in full sun. In partial shade, expect less flowering or a looser shape, and choose a variety rated for those conditions.
How far apart should I plant tall grasses?
Use the mature width on the plant label as your guide. For a continuous screen, spacing plants roughly one mature width apart allows them to fill in without immediately crowding; adjust for the desired look and cultivar.
When should I cut ornamental grasses back?
Cut deciduous grasses back in late winter or early spring, before new shoots emerge. Leave evergreen types mostly uncut and comb or trim away dead leaves as needed.
Are tall ornamental grasses low maintenance?
Many are once established, but they still need watering while young, occasional division, and seasonal cleanup. Maintenance varies by species, climate, and whether the grass spreads or self-seeds.
Can I grow a tall narrow grass in a pot?
Yes, if the container is large, stable, and has drainage holes. Choose a variety with a suitable mature size, water more often than you would in the ground, and protect the pot’s roots from severe winter cold where necessary.