Getting it to bloom

Why won't my Pale-Spike Lobelia bloom? (and how to make it flower)

Also called Pale-Spike Lobelia, Spiked Lobelia, Pale-Spiked Lobelia (Lobelia spicata).

More about pale-spike lobelia

About Pale-Spike Lobelia

Lobelia spicata · also called Pale-Spike Lobelia, Spiked Lobelia · flowering

Pale-spike lobelia is a slender native perennial wildflower native to prairies, meadows, and open woodlands from southeastern Canada south to Georgia and Louisiana. It produces elongated spikes of small pale lavender to white flowers in early to mid-summer and tolerates a wider range of soil moisture than most lobelias. The most important care fact is that it tends to flop without the support of neighbouring plants or grasses — plant it within a prairie matrix rather than as a lone specimen. The whole plant contains lobeline alkaloids and is toxic to cats and dogs.

Plant type: flowering

The reasons pale-spike lobelia isn't blooming

Almost every non-blooming pale-spike lobelia 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 pale-spike lobelia 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 pale-spike lobelia to flower

Maximise sun. Give pale-spike lobelia 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 pale-spike lobelia and get the feeding right with the pale-spike lobelia 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

Pale-Spike Lobelia 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 pale-spike lobelia care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Pale-Spike Lobelia blooming — frequently asked questions

Why won't my pale-spike lobelia flower?

Pale-Spike Lobelia 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 pale-spike lobelia bloom?

Give pale-spike lobelia 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 pale-spike lobelia normally bloom?