Getting it to bloom

Why won't my Tall Bluebells bloom? (and how to make it flower)

Also called Tall Bluebells, Alaska Tall Bluebells, Northern Bluebells, Tall Lungwort (Mertensia paniculata).

More about tall bluebells

About Tall Bluebells

Mertensia paniculata · also called Tall Bluebells, Alaska Tall Bluebells · flowering

Mertensia paniculata is a vigorous North American native perennial from boreal and montane habitats, bearing branched clusters of pendant, bright-blue (occasionally pink or white) bell-shaped flowers in late spring to midsummer. Thriving in moist, partly shaded conditions, it naturalises readily in woodland gardens and streamside plantings in zones 3–8.

Plant type: flowering

Watch for — Premature dormancy: Plants die back early if soils dry out in summer. This is especially common in warm or drought-prone climates. Mulch heavily and maintain consistent irrigation through the growing season to achieve full-season flowering.

The reasons tall bluebells isn't blooming

Almost every non-blooming tall bluebells 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 tall bluebells 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 tall bluebells to flower

Maximise sun. Give tall bluebells 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 tall bluebells and get the feeding right with the tall bluebells 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

Tall Bluebells 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 tall bluebells care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Tall Bluebells blooming — frequently asked questions

Why won't my tall bluebells flower?

Tall Bluebells 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 tall bluebells bloom?

Give tall bluebells 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 tall bluebells normally bloom?