Getting it to bloom

Why won't my Brunnera macrophylla 'Jack Frost' bloom? (and how to make it flower)

Also called Jack Frost Siberian bugloss, Jack Frost brunnera (Brunnera macrophylla 'Jack Frost').

More about brunnera macrophylla 'jack frost'

About Brunnera macrophylla 'Jack Frost'

Brunnera macrophylla 'Jack Frost' · also called Jack Frost Siberian bugloss, Jack Frost brunnera · flowering

An award-winning shade perennial grown for its frosted, silver-overlaid heart-shaped leaves traced with green veins and margins. In mid to late spring it throws up airy sprays of tiny sky-blue, forget-me-not flowers. A clump-forming, low-maintenance groundcover for moist woodland shade, lighting up dark corners all season with metallic foliage.

Plant type: flowering

The reasons brunnera macrophylla 'jack frost' isn't blooming

Almost every non-blooming brunnera macrophylla 'jack frost' 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 brunnera macrophylla 'jack frost' 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 brunnera macrophylla 'jack frost' to flower

Maximise sun. Give brunnera macrophylla 'jack frost' 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 brunnera macrophylla 'jack frost' and get the feeding right with the brunnera macrophylla 'jack frost' 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

Brunnera macrophylla 'Jack Frost' 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 brunnera macrophylla 'jack frost' care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Brunnera macrophylla 'Jack Frost' blooming — frequently asked questions

Why won't my brunnera macrophylla 'jack frost' flower?

Brunnera macrophylla 'Jack Frost' 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 brunnera macrophylla 'jack frost' bloom?

Give brunnera macrophylla 'jack frost' 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 brunnera macrophylla 'jack frost' normally bloom?