Getting it to bloom

Why won't my Ruellia Brittoniana bloom? (and how to make it flower)

Also called Mexican petunia, Britton's wild petunia, Ruellia (Ruellia simplex).

More about ruellia brittoniana

About Ruellia Brittoniana

Ruellia simplex · also called Mexican petunia, Britton's wild petunia · flowering

Ruellia simplex is a tough, fast-growing perennial grown for its slim upright stems and near-continuous flush of petunia-like purple-blue flowers through the warm months. Despite the common name it is not a true petunia. Heat- and drought-tolerant once established, it thrives in sun and damp soils alike, but is invasive in warm regions and should be sited with care.

Plant type: flowering

Watch for — Legginess in shade: In too little light it stretches, flops and flowers poorly. Plant in full sun for compact, well-branched, free-flowering growth, or choose a dwarf cultivar for tighter habit.

The reasons ruellia brittoniana isn't blooming

Almost every non-blooming ruellia brittoniana 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 ruellia brittoniana 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 ruellia brittoniana to flower

Maximise sun. Give ruellia brittoniana 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 ruellia brittoniana and get the feeding right with the ruellia brittoniana 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

Ruellia Brittoniana 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 ruellia brittoniana care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Ruellia Brittoniana blooming — frequently asked questions

Why won't my ruellia brittoniana flower?

Ruellia Brittoniana 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 ruellia brittoniana bloom?

Give ruellia brittoniana 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 ruellia brittoniana normally bloom?