Getting it to bloom

Why won't my Japanese Blood Grass bloom? (and how to make it flower)

Also called japanese blood grass, red baron blood grass (Imperata cylindrica 'Rubra').

More about japanese blood grass

About Japanese Blood Grass

Imperata cylindrica 'Rubra' · also called japanese blood grass, red baron blood grass · flowering

Imperata cylindrica 'Rubra', Japanese blood grass, is an upright ornamental grass with green blades whose upper halves turn blood-red, glowing translucent when backlit. The colour deepens through summer into autumn. It prefers full sun to part shade and moist, well-drained soil. Note its parent species is an invasive noxious weed, so plant the ornamental form responsibly and watch for green reversions.

Plant type: flowering

The reasons japanese blood grass isn't blooming

Almost every non-blooming japanese blood grass 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 japanese blood grass 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 japanese blood grass to flower

Maximise sun. Give japanese blood grass 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 japanese blood grass and get the feeding right with the japanese blood grass 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

Japanese Blood Grass 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 japanese blood grass care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Japanese Blood Grass blooming — frequently asked questions

Why won't my japanese blood grass flower?

Japanese Blood Grass 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 japanese blood grass bloom?

Give japanese blood grass 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 japanese blood grass normally bloom?