Getting it to bloom

Why won't my Smooth Cordgrass bloom? (and how to make it flower)

Also called Smooth cordgrass, Saltmarsh cordgrass, Oystergrass (Spartina alterniflora).

More about smooth cordgrass

About Smooth Cordgrass

Spartina alterniflora · also called Smooth cordgrass, Saltmarsh cordgrass · flowering

Spartina alterniflora is a robust, intertidal perennial grass native to the Atlantic and Gulf coasts of North America, where it is the dominant vegetation of low saltmarsh. It tolerates complete tidal flooding, high salinity, and anaerobic mud through specialised aerenchyma tissue. The most critical care fact is that it requires tidal, saline, or brackish intertidal conditions and is unsuitable for conventional gardens — it is a specialist saltmarsh restoration grass. Outside North America, especially in the UK, China, and Australasia, it is classified as a highly invasive species and subject to control orders. Smooth cordgrass is not listed as toxic by the ASPCA and is considered non-toxic to pets.

Plant type: flowering

The reasons smooth cordgrass isn't blooming

Almost every non-blooming smooth cordgrass traces back to one of these, roughly in order of how common they are:

Too little sun — most of these need full sun (or very bright light) to flower well; shade gives leaves, not blooms.
Too much nitrogen feed, driving lush foliage at the expense of flowers (very common with general or lawn feeds).
The plant has not been deadheaded, so it stops flowering once it sets seed.
Irregular watering — drought or waterlogging at the budding stage makes buds abort.
It is still too young or was checked by a transplant and is rebuilding before flowering.

Feeding smooth cordgrass a high-nitrogen general feed and growing it in too little sun — you get a big leafy plant and almost no flowers.

The fix — how to get smooth cordgrass to flower

Maximise sun. Give smooth cordgrass the sunniest spot you have — for most bedding and fruiting plants, more direct light directly means more flowers.
Switch the feed. Move off high-nitrogen feeds and use a higher-potassium "bloom" or tomato-type feed as it comes into flower.
Deadhead regularly. Remove spent flowers often to keep it producing more rather than stopping to set seed.
Water consistently. Keep moisture even through budding and flowering — drought-then-flood swings make buds drop.

Light and feeding do most of the heavy lifting here. Dial in the spot with the light guide for smooth cordgrass and get the feeding right with the smooth cordgrass fertilising schedule — the wrong feed (too much nitrogen) is one of the most common silent reasons a healthy plant makes leaves instead of flowers.

Bloom season and what to expect

Smooth Cordgrass flowers across its growing season (mostly summer) and, kept fed and deadheaded, can bloom for many weeks or right up to frost.

Post-bloom care so it flowers again

Deadhead, keep feeding lightly, and many will rebloom; collect seed from the best plants at the end of the season if you want to grow them again.

For everything else this plant needs day to day, see the full smooth cordgrass care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Smooth Cordgrass blooming — frequently asked questions

Why won't my smooth cordgrass flower?

Smooth Cordgrass blooms on the season's growth given enough sun, warmth and the right feed — there is no cold or photoperiod trick, just good growing conditions and a bloom-leaning feed. The most common reason it is not happening: Too little sun — most of these need full sun (or very bright light) to flower well; shade gives leaves, not blooms.

How do I make smooth cordgrass bloom?

Give smooth cordgrass the sunniest spot you have — for most bedding and fruiting plants, more direct light directly means more flowers. Move off high-nitrogen feeds and use a higher-potassium "bloom" or tomato-type feed as it comes into flower.

When does smooth cordgrass normally bloom?