Plant ID: It Can’t Be Poison Hemlock

Belief and facts really fight each other when I’m learning something new.

Poison Hemlock 1

I have been trying to ID this plant I see all over popular San Francisco trails. Very pretty, it’s a tall plant with soft white flowers. I thought I had IDed it as Cow Parsnip, then I read that Cow Parsnip leaves are large and broad. The leaves on this plant are parsley-like, fine and frilly. Then I thought it was Cow Parsley, a relative of Cow Parsnip. Then I thought it was Giant Hogweed, because it is up to eight feet tall, but again, this plant did not have large leaves like Giant Hogweed. I had already ruled out Queen Anne’s Lace. This plant is too big and doesn’t have the dark red dot in the center and hairy stems. Then I thought Wild Carrot. No, not a nest-like umbel. What is it?

Throughout my search of reference material for all the above mentioned plants,  I saw Poison Hemlock mentioned as a look-a-like. All sources noted the tell-tale differences of Hemlock: the reddish purple marks on smooth stems, the carrot/parsley-like leaves, but even with my many photos showing evidence of this, I just could not believe a national park would have this growing all over well-trod trails. I have an image in my head that a deadly plant with its long history of poisoning would be elusive, lurking in a dark garden somewhere. But in reality it is just another common plant that doesn’t agree with the human body if ingested, like so many plants.

So yes, after I took my newly compiled semi-scientific list of questions out into the field and got my answers, sat down and compared them with reliable research materials, I can 99% say it is Poison Hemlock. The 1% of doubt I would like dispelled by someone with many more years of knowledge than me.

My own false beliefs of safety, because a national park is a beautiful place with lovely sites, could have proved fatal if I were a novice forager. Luckily I’m not into tasting things I can’t ID, but I did crush and sniff the flowers and leaves. Do I feel a tingle? Maybe it’s just in my head. Lesson learned. Only knowledge gained by a lot of open-minded researching will give you the truth when IDing plants.

Socrates Tea of Choice

Poison Hemlock StemPoison Hemlock Leaf


My Beginners Plant ID Checklist:

Height and width of whole plant : 4′-8′ tall, 2-4 wide

Height of flowering part: umbel heads are anywhere from 6″-10″ wide with little umbels coming off of it that are 1″ -2″ wide

Whole flowering head color, size, shape, connection to the stem, scent when whole and crushed: white flowers with what looks like 2 creamy center dots squished together. Petals and leaves smelled like musty corn tortillas when crushed.

Petal quantity, color, size, shape: 5 white petals with 3 little antennae-like things in full flowering plant

Stamen, pistil, stigma size, shape, quantity: none

Leaf color, size, shape, scent when whole and crushed: leaves are bipinnately compound, lobed individual leaflets, carrot/parsley-like, smooth, not fuzzy

Stem color: stem is green, with red to purplish streaks or splotches on lower part

Stem size, shape, texture, hollow or filled in: slightly ridged, round stem in varying diameters, hairless, fibrous, hollow. When squeezed hard it will squash down

Branching patterns on stem: alternate stem from main branch, with three flower heads from each branch

Leaf attachment pattern to main stem: n/a

Where it’s growing: Presidio Battery to Bluffs trail, seaside scrubland

When it’s growing: have witnessed it in May, June, July

Is the plant just blooming or is it wilting: all life stages

What’s growing around it: wild mustard, wild radish, yarrow, ivy, blackberry shrubs

Thanks for reading,

Empress Norma


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