To propagate Sea Oat Grass, the most effective method is through division, where you dig up a clump of the plant in mid-spring to mid-summer and carefully separate it into sections, ensuring each section has roots and shoots, using a sharp spade or knife; you can also propagate Sea Oat Grass from seed, but be aware that it can spread aggressively due to its rhizomatous nature. 

Key points about propagating Sea Oat Grass:

Best method: Division is generally considered the best way to propagate Sea Oat Grass. 

When to divide: Mid-spring to mid-summer is the ideal time to divide the plant. 

Preparation: Before dividing, water the clump thoroughly to make digging easier. 

Division process: Dig around the clump to expose the roots. 

Use a sharp spade or knife to cut the clump into sections.  Ensure each section has a good root system and shoots.  Replant the divided sections in a new location. 

Propagating from seed:

Harvesting seeds: Collect seeds in the fall when they are mature. 

Stratification: Some recommend cold stratification (placing seeds in a moist paper towel and refrigerating for a period) to improve germination. 

Planting: Sow seeds directly in the ground in late summer or early fall. 

Important considerations:

Potential for spread: Sea Oats can spread aggressively due to their rhizomes, so be mindful of where you plant them and manage their growth. 

Native varieties: If possible, try to source seeds or plants from a local native plant nursery to ensure you are planting a variety well-suited to your region.