The bobbing flat seedheads of northern sea oats are distinctive, almost looking like little buff-to-bronze fish. It's one of the best ornamental grasses for partial shade, although it grows well in full sun. The arching seed heads mature to golden bronze and are effective in fresh or dried arrangements. Leave this plant standing in winter if you like—it's attractive with a dusting of snow. However, if you want to prevent this prolific reseeder from popping up everywhere, cut off the seed heads in fall.
Add texture to your landscape with northern sea oats. This easy-to-grow native grass stands 2-4 feet tall and reveals flat green seed heads in midsummer that slowly turn bronze, then copper by early fall. The slightest breeze flowing through a clump of grass will rustle the dry seed heads, creating a pleasing type of garden music. Northern sea oats are a fabulous cutting flower. Snip the seed stems shortly after they begin to turn bronze for a long-lasting fresh or dried bouquet.
Northern Sea Oats Overview
Where to Plant Northern Sea Oats
Plant northern sea oats in moist, fertile soil that drains well in a part-shade or full-sun location. Northern sea oats are native to moist woodland edges, which makes them a great addition to part-shade gardens. Create a woodland meadow with a collection of shade-tolerant grasses. You'll love the easy-care aspect of a meadow planting and count on a bounty of color and texture year-round. Other great grasses for part-shade sites include tufted hair grass (Deschampsia cespitosa), Korean feather reed grass (Calamagrostis brachytricha), Japanese forest grass (Hakonechloa macra), and sedges.
How and When to Plant Northern Sea Oats
Northern sea oats can be planted in late spring or in the fall. Sow the seeds 1/4 inch deep in pots filled with potting soil. Keep the soil moist but not soggy, and place the pots in an area that stays at about 70°F until the seeds germinate. When the seedlings are 2-3 inches tall, transplant them into a prepared garden bed.
In areas where the outdoor temperature remains at 70°F or higher, sow the seed outside 1/4 inch deep in a prepared garden bed. Germination occurs in 7-14 days.
Northern Sea Oats Care Tips
Light
Northern sea oats are an excellent grass for part-shade sites. Many grasses demand full sun for strong, upright growth and good color, but this tough perennial grows best in partial shade. Count on its leaves to take on a dark green color in partial shade; plants grown in full sun have light green foliage.
Soil and Water
Northern sea oats grass grows well in fertile soil and moist, well-drained sites. Once it establishes a strong root system, it tolerates drought with ease.
Temperature and Humidity
Northern sea oats grows best in areas with moderate summer heat and average humidity. It doesn't do well in hot and humid areas in the South.
Fertilizer
Fertile soil is necessary for northern sea oats to be at its best. Apply compost annually.
Pruning
Winter interest is one of the benefits of growing northern sea oats, so leave it standing throughout the cold weather. In early spring, cut back the plant to a couple of inches above the ground to prepare it for new growth.
Potting and Repotting Northern Sea Oats
Northern sea oats is also a good choice for patio containers. Plant it in the middle of a large container with good drainage and surround it with shorter plants that enjoy the same fertile, moist soil environment favored by northern sea oats. The grass may require more frequent watering when planted in a container.
Pests and Problems
Pests don't bother northern sea oats. The grass is deer-resistant, although a hungry deer might take a bite when no other food is available. Some birds consume the seeds, but the plant produces many seeds, so plenty is usually left for self-seeding (which can be a boon or a problem for gardeners who want to control the grass).
How to Propagate Northern Sea Oats
There's rarely a need to plant more than one clump of northern sea oats. This native grass spreads slowly through its rhizome growth habit and quickly through reseeding. Prolific seed heads cast out seed in fall, and the following spring will reveal a host of new northern sea oats plants. The seedlings are easy to remove, but the task can be time-consuming. Prevent bold reseeding by cutting off seed stalks in late summer.
The best method for propagating northern sea oats is division. In mid-spring to midsummer, dig up a clump of the grass. Use a sharp spade or knife to cut the clump into two or more sections, each containing a portion of roots, rhizomes, and shoots. Immediately plant the section in a prepared bed of fertile, moist, well-draining soil. Don't let the roots dry out as you work. If there is a delay, put the sections in a bucket of water.
Types of Northern Sea Oats
Species Northern Sea Oats
The blue-green foliage of Chasmanthium latifolium clump-forming perennial grass grows 2-4 feet tall with blue-green and bamboo-like leaves. They sometimes turn bright gold in the fall when planted in sunny sites. The seed heads start green and then turn gold and bronze. They are striking in cut flower arrangements, Zones 3-9
'River Mist' Northern Sea Oats
Chasmanthium' River Mist' adds a bit of excitement to traditional northern sea oats in the form of variegation patterns. 'River Mist' looks much like the species version but has bright green and white striped bamboo-type foliage. In late summer, it forms beautiful silvery green seed heads. 'River Mist' grows up to 30 inches tall. Zones 4-9
Northern Sea Oats Companion Plants
Turtlehead
Turtlehead is a native perennial that gets its name from the shape of its unusual flowers, which resemble the heads of snapping turtles. It's a good choice for heavy, wet soils and spreads to form dense colonies of upright stems bearing pink, rose, or white flowers from late summer into fall. It grows best in some shade but tolerates full sun with adequate moisture.
Leadwort
For a fall show, plant leadwort. Its gentian-blue, late-season flowers often continue to bloom even as the foliage turns brilliant red-orange in fall, making an outstanding autumn display. This plant is also sometimes called plumbago, but it's different from shrubby tropical plumbago. Use it as a groundcover that spreads well when in conditions it likes—dry sites in full sun to partial shade.
Asters
Asters get their name from the Latin word for "star," and their flowers are indeed the superstars of the fall garden. Some types of this native plant can reach up to 6 feet with flowers in white and pink, rich purples, and showy lavenders. Not all asters are fall bloomers. Extend the season by growing some of the summer bloomers, as well. Some are naturally compact; tall types that grow more than 2 feet tall benefit from staking or an early-season pinching or cutting back by about one-third in July to keep the plant compact.
Garden Plan for Nothern Sea Oats
Clay Soil Garden Plan
This clay garden plan will enable you to enjoy a colorful, thriving garden despite your sometimes stubbornly wet, sometimes crust-like soil. This design can handle (even thrive in) the tough conditions common to clay soil.
Frequently Asked Questions
- Does northern sea oats grass grow well in coastal communities?Northern sea oats are salt-tolerant, which makes the grass an excellent option for seaside gardeners.
Northern sea oats are salt-tolerant, which makes the grass an excellent option for seaside gardeners.
- How long does northern sea oats grass live?When grown in optimal conditions, the perennial grass lives up to 10 years. It reseeds freely, so acquiring new plants for a continuous supply isn't difficult.
When grown in optimal conditions, the perennial grass lives up to 10 years. It reseeds freely, so acquiring new plants for a continuous supply isn't difficult.
- Is northern sea oats toxic?No, in fact northern sea oats have edible seeds that can be added to salads, much like sunflower seeds. However, don't eat the seeds if pesticides have been used on the plants.
No, in fact northern sea oats have edible seeds that can be added to salads, much like sunflower seeds. However, don't eat the seeds if pesticides have been used on the plants.