Five is false, ten is true

a patch of white flowers in the sun

Rue anemone or false rue anemone?

another patch of white flowers in the sun

The previous two pictures look really similar. (There’s even a log in each!) They’re white flowers, approximately the same size, with very similar leaves. But they’re different: all of the flowers in the first photo have five petals, but only some of the flowers in the second photo have five petals, and most have more than five.

I can always remember that there is a distinction in the petal numbers, but I haven’t been able to remember which is which without looking it up. Thank goodness for

yet another patch of white flowers, each with five petals

Color might help: if it’s pink, it’s rue anemone. But with such similar common names, what are the chances I’ll remember that? Slim.

closeup of four pinkish flowers, one with seven petals, two with six, and one with five

In addition, both can be white, so it’s not safe to rely on color. So it’s back to counting the petals. False rue anemone always has five petals; true rue anemone has between five and ten.

closeup of a white flower with eight petals and several smaller flowers drooping away

However, that rule has never stuck with me. I have to keep learning it and re-learning it. Even in my own garden — where I have one of these flowers but not the other…

six white flowers, two with five petals, one with six, one unknown, and two missing several petals

… the only way I know for sure is to look at the tag.

an out-of-focus white flower next to a plant tag that says rue anemone

This year, I posted this problem on Instagram and asked if anyone has a mnemonic to help. Within a couple hours, a new Instagram friend, Jenny Stratton, responded with this spur-of-the-moment suggestion:

Five is false, ten is true?

Let’s give it a try:

sunny shot that focuses on a couple flowers in the foreground, with many more blurred in the background
All of these flowers have five petals, so it’s false rue anemone


focus on one pinkish flower, with many more around it
All of these flowers have [up to] ten petals, so it’s [true] rue anemone
It works! And I’ve managed to remember this saying for two weeks.

closeup of one pinkish flower with seven petals

One problem is that five petals could mean either flower. But a patch of true rue anemone, as far as I have seen, never has all five-petal flowers. In fact, I usually don’t see any with five; it’s usually six or eight. As long as I am not in a hurry and look at the entire patch of flowers instead of just one individual, I’ll get it.

closeup of one white flower with five petals, with half a dozen more in the background

Learn more about these flowers

1 Comment

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  1. This is a great lesson, and I’m so glad that I could contribute to it! I had never tried memorizing the difference before, since (to my knowledge) the only time I’d seen Thalictrum thalictroides (Rue anemone) was pre-identified on an herbarium sheet. Really enjoying the sweet reminder of Midwestern flora on your blog :) :)


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