Getting it to bloom

Why won't my Crown Vetch bloom? (and how to make it flower)

Also called Crown Vetch, Purple Crown Vetch, Axseed (Coronilla varia).

More about crown vetch

About Crown Vetch

Coronilla varia · also called Crown Vetch, Purple Crown Vetch · flowering

Crown Vetch is a sprawling, nitrogen-fixing perennial legume native to Europe and western Asia, widely planted in North America for erosion control on roadsides and slopes and listed as invasive in several US states. It produces dense heads of pink-purple and white pea-like flowers from June to August and spreads aggressively via rhizomes and self-seeding, quickly out-competing native vegetation. The most important consideration in garden use is its invasive potential — site carefully and contain its spread. Crown Vetch is toxic to horses and should be treated as mildly toxic for cats and dogs.

Plant type: flowering

The reasons crown vetch isn't blooming

Almost every non-blooming crown vetch 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 crown vetch 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 crown vetch to flower

Maximise sun. Give crown vetch 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 crown vetch and get the feeding right with the crown vetch 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

Crown Vetch 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 crown vetch care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Crown Vetch blooming — frequently asked questions

Why won't my crown vetch flower?

Crown Vetch 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 crown vetch bloom?

Give crown vetch 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 crown vetch normally bloom?