Getting it to bloom

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

Also called purple fountain grass, red fountain grass (Pennisetum setaceum 'Rubrum').

More about purple fountain grass

About Purple Fountain Grass

Pennisetum setaceum 'Rubrum' · also called purple fountain grass, red fountain grass · flowering

Purple fountain grass is a tender ornamental grass with burgundy-red foliage and arching, foxtail-like purple plumes from summer to frost. It forms a graceful fountain-shaped mound and is grown as an annual or container specimen in cold climates, overwintered only where frost is absent. Heat-loving and sun-hungry, it adds rich colour and movement.

Plant type: flowering

Watch for — Green, dull foliage: Insufficient sun fades the purple colour and reduces flowering; move to the brightest possible spot.

The reasons purple fountain grass isn't blooming

Almost every non-blooming purple fountain 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 purple fountain 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 purple fountain grass to flower

Maximise sun. Give purple fountain 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 purple fountain grass and get the feeding right with the purple fountain 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

Purple Fountain 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 purple fountain grass care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Purple Fountain Grass blooming — frequently asked questions

Why won't my purple fountain grass flower?

Purple Fountain 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 purple fountain grass bloom?

Give purple fountain 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 purple fountain grass normally bloom?