Getting it to bloom

Why won't my Rough Chervil bloom? (and how to make it flower)

Also called Rough Chervil, Rough Cow Parsley (Chaerophyllum temulum).

More about rough chervil

About Rough Chervil

Chaerophyllum temulum · also called Rough Chervil, Rough Cow Parsley · flowering

Rough chervil is a native British and European biennial of hedgerows, roadsides, and woodland edges, belonging to the carrot family (Apiaceae). It produces flat-topped clusters of tiny white flowers from May to July atop stiff, purple-spotted, hairy stems that are distinctively swollen below each leaf node — a key identification feature that separates it from edible umbellifers. The single most important care fact is that it is toxic to people and animals if ingested: it must never be confused with edible parsley, chervil, or cow parsley. It is toxic and must be kept away from pets.

Plant type: flowering

The reasons rough chervil isn't blooming

Almost every non-blooming rough chervil 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 rough chervil 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 rough chervil to flower

Maximise sun. Give rough chervil 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 rough chervil and get the feeding right with the rough chervil 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

Rough Chervil 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 rough chervil care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Rough Chervil blooming — frequently asked questions

Why won't my rough chervil flower?

Rough Chervil 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 rough chervil bloom?

Give rough chervil 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 rough chervil normally bloom?