Getting it to bloom

Why won't my Lobelia erinus 'Cascade Blue' bloom? (and how to make it flower)

Also called Cascade Blue Lobelia, Trailing Blue Lobelia (Lobelia erinus 'Cascade Blue').

More about lobelia erinus 'cascade blue'

About Lobelia erinus 'Cascade Blue'

Lobelia erinus 'Cascade Blue' · also called Cascade Blue Lobelia, Trailing Blue Lobelia · flowering

'Cascade Blue' is a trailing edging lobelia smothered in small, deep-blue flowers from late spring to autumn. A tender annual ideal for hanging baskets, window boxes and container edges, it spills attractively over rims. It performs best in cool, moist conditions with sun to part shade and may pause flowering in summer heat.

Plant type: flowering

Watch for — Mid-summer flowering pause: Heat stalls bloom and growth; shear back by a third, water well and feed to revive a second flush as temperatures ease.

The reasons lobelia erinus 'cascade blue' isn't blooming

Almost every non-blooming lobelia erinus 'cascade blue' 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 lobelia erinus 'cascade blue' 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 lobelia erinus 'cascade blue' to flower

Maximise sun. Give lobelia erinus 'cascade blue' 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 lobelia erinus 'cascade blue' and get the feeding right with the lobelia erinus 'cascade blue' 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

Lobelia erinus 'Cascade Blue' 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 lobelia erinus 'cascade blue' care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Lobelia erinus 'Cascade Blue' blooming — frequently asked questions

Why won't my lobelia erinus 'cascade blue' flower?

Lobelia erinus 'Cascade Blue' 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 lobelia erinus 'cascade blue' bloom?

Give lobelia erinus 'cascade blue' 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 lobelia erinus 'cascade blue' normally bloom?