Northern sea oats (Chasmanthium latifolium) tolerates shade better than most other varieties of ornamental grasses. However, you can also grow it in direct sunlight if you make sure to give it enough water. This species forms enormous colonies that help protect riverbanks from insidious erosion. The seed stalks make a welcome addition to dried flower arrangements.
I. Appearance and CharacteristicsÂ
Chasmanthium latifolium, known as fish-on-a-fishing-pole, northern wood-oats, inland sea oats, northern sea oats, and river oats is a species of grass native to the central and eastern United States, Manitoba, and northeastern Mexico; it grows as far north as Pennsylvania and Michigan, where it is a threatened species. The species was previously classified as Uniola latifolia (André Michaux).
Chasmanthium latifolium is a cool-season, rhizomatous, perennial grass with culms about 1 m [3 feet] tall. The inflorescence is an open, nodding panicle of laterally compressed (flattened) spikelets. The plant typically grows in wooded areas and riparian zones.
It is used in landscaping in North America, where it is noted as a relatively rare native grass that thrives in partial shade; the plant is recommended for USDA hardiness zones 3–9 in acidic sands, loams, and clays.
It is a larval host plant for the Northern Pearly-Eye, and its seeds are food for birds and mammals. It is also eaten by the caterpillars of the pepper and salt skipper, Bell’s roadside skipper, and bronzed roadside skipper butterflies.
II. How to Grow and Care
Sunlight
Give northern sea oats full sun to partial sun. While it will survive if grown in partial shade, it will not thrive to the same degree: Flowering will be reduced, and its fall color will not be as strong. This is an important consideration since northern sea oats is grown mainly for its flower heads and for its fall color.
However, the more sun it receives, the more water you should give it; so be prepared to provide it with more care (irrigation) if you are growing it in an area with full sun. If low-maintenance landscaping is more important to you than optimal performance, grow it in partial sun so that you can cut back on watering. At the southerly end of its range, the summers are so hot that it is best to grow northern sea oats in partial sun or even in partial shade.
Temperature and Humidity
Northern sea oats perform best in climates with moderate summer heat and humidity. It does not perform well in the Deep South, which is why the most southerly USDA zone it is listed for is zone 9.
Watering
Northern sea oats has only moderate moisture needs if grown in partial sun or partial shade, but it does not like for its soil to dry out completely. Aim for a consistently moist soil, especially during the heat of summer.
Soil
Northern sea oats likes well-drained, fertile ground. A loamy soil fortified with compost is ideal.
Fertilizing
Northern sea oats need fertile soil to perform optimally, so feed it annually with compost or manure tea.
Propagation
The best (easiest) way to propagate northern sea oats is through division. Divide and transplant it any time between mid-spring and early summer. Do not let its soil dry out completely during this operation.
How to Grow From Seed
Northern sea oats are also easy to start from seed. No special steps are required to get its seed to germinate. You can either collect the seed in fall or buy it; the seed is readily available for sale online.
Pests and Diseases
Northern sea oats are bothered by few pests or diseases. Most importantly, the deer leave it alone; because of their size (and thus their ability to eat so much), deer, where they are present, are typically the landscaper’s worst nightmare.
How to Get to Bloom
Provided that they have been planted in full sun, northern sea oats will readily start blooming in the late summer each year, with little extra help from you. The flower head, which imperceptibly morphs into a seed head in fall, measures about 1 inch long and wide; it is razor-thin. For optimal flowering, simply keep the soil evenly moist and give the plant an annual feeding. Since the flower head is the main draw of the plant, do not deadhead.
III. Uses and BenefitsÂ
A highly adaptable, hardy ornamental grass, northern sea oats is often used as a tall ground cover in landscaping. Since it is tolerant of shade, it can be planted in tree-covered or treeline surfaces with no issues. Also, it can be included in flower beds, where it can form a decorative backdrop for flowering plants or take mid-position with taller plants in the back.
IV. Types of Northern Sea Oats
Chasmanthium latifolium is one of five species of Chasmanthium, but the other four are not as commonly grown. The other four species are:
- Chasmanthium nitidum (shiny wood-oats)
- Chasmanthium ornithorhynchum (bird-bill wood-oats)
- Chasmanthium sessiliflorum (long-leaf wood-oats)
- Chasmanthium laxum (slender wood-oats)
- But some nurseries and online catalogs do carry a variegated leaf cultivar of Chasmanthium latifolium known as ‘River Mist’. As with many variegated plant cultivars, it likes a little more shade than the species plant.
