Getting it to bloom

Why won't my Bulbous Corydalis bloom? (and how to make it flower)

Also called Bulbous corydalis, Bulbous fumewort, Spring fumewort (Corydalis bulbosa).

More about bulbous corydalis

About Bulbous Corydalis

Corydalis bulbosa · also called Bulbous corydalis, Bulbous fumewort · flowering

Corydalis bulbosa (syn. Corydalis solida subsp. solida in some authorities) is a spring-ephemeral perennial native to deciduous woodlands and shaded banks across Europe and western Asia, producing dense racemes of pink-purple to reddish-purple spurred flowers from March to May before dying back completely by early summer. It grows from a solid, starchy tuber and naturalises freely under deciduous trees or in shaded borders. It asks for little more than leafy, humus-rich soil and a cool, partially shaded position. The plant contains isoquinoline alkaloids and is toxic to cats and dogs.

Plant type: flowering

The reasons bulbous corydalis isn't blooming

Almost every non-blooming bulbous corydalis 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 bulbous corydalis 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 bulbous corydalis to flower

Maximise sun. Give bulbous corydalis 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 bulbous corydalis and get the feeding right with the bulbous corydalis 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

Bulbous Corydalis 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 bulbous corydalis care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Bulbous Corydalis blooming — frequently asked questions

Why won't my bulbous corydalis flower?

Bulbous Corydalis 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 bulbous corydalis bloom?

Give bulbous corydalis 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 bulbous corydalis normally bloom?