Getting it to bloom

Why won't my Whorled Water Milfoil bloom? (and how to make it flower)

Also called Whorled Water Milfoil, Whorled Milfoil (Myriophyllum verticillatum).

More about whorled water milfoil

About Whorled Water Milfoil

Myriophyllum verticillatum · also called Whorled Water Milfoil, Whorled Milfoil · flowering

Whorled Water Milfoil is a submerged aquatic perennial native to temperate Northern Hemisphere ponds and slow streams. Its feathery, whorled foliage oxygenates water and shelters fish fry. Best grown in full sun in still or gently moving water 30–100 cm deep. Hardy across a wide climate range; no soil or humidity management needed.

Plant type: flowering

The reasons whorled water milfoil isn't blooming

Almost every non-blooming whorled water milfoil 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 whorled water milfoil 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 whorled water milfoil to flower

Maximise sun. Give whorled water milfoil 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 whorled water milfoil and get the feeding right with the whorled water milfoil 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

Whorled Water Milfoil 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 whorled water milfoil care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Whorled Water Milfoil blooming — frequently asked questions

Why won't my whorled water milfoil flower?

Whorled Water Milfoil 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 whorled water milfoil bloom?

Give whorled water milfoil 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 whorled water milfoil normally bloom?