Stinging Nettle. I only encountered it ONCE in my jungle in NJ. HORRIBLE PAIN! Apparently not common here, out in the yard a LOT and only got stung once. thank goodness. It supposedly has a number of medicinal uses.

I just heard about a neighbor who planted it around her mailbox to deter theives!

the one in the picture is the annual version, Urtica urens

that prefers to grow in disturbed soil, like in veggie beds

it does hurt quite a bit, grows about 8 inches high

the other one is perennial

Urtica dioica, it hurts as well and IME tiungles hours after, but no seroius skin issues

it loves nitrogene and thrives in good soils

grows 4-6 feet tall

at hte edges of muck heaps

at banks that get flooded regurlarly

and re the letter box, how is the mail man supposed to get near it, just sayin...

I ran into the shorter version nettle as a child camping with my family. If memory serves me right, it was mostly annoying. A few years ago we had stopped at a State rest area where there were trails to stretch ones legs, walk a dog, restrooms and coffee. I took a short walk, saw an odd looking barely noticeable flower on a shrub I didn't recognize and reached out to see if had scent. A big mistake. That nettle (4-5' tall and arching) stung like heck, it really hurt. We poured a bottle of water over my hand, then tried 70% alcohol from the first aid kit. Neither helped. I went inside the ladies room and washed with soap and water. This was late morning and it hurt all day until I went to bed that night. No rash or anything really apparent but there was pain, diminished only a little with tylenol. If I see it again, I'll know what it is. I've spent plenty of time in our more local woods and never come across that plant....2 hours away there was quite a bit of it growing under big leaf maple.

A "barely noticeable flower on a shrub" doesn't really sound like a stinging nettle. It isn't a shrub and the flower is a kind of dusty grey green catkin, not something one would expect to smell good. I wonder if it was something else?

I collect nettles every year in late spring and dry them as an easy super-nutritious vegetable. Excellent! (There's no stinging effect when they are cooked or dried)

Morz8 and floraluk2: I wonder if it might have been ”devil’s club” - Oplopanax horridus

Oplopanax horridus has alternate, palmate leaves. The OP pics appear to be opposite, simple leafed.

Both Urtica dioica and Urtica urens grow on the west coast. I've read that urens is more painful. Urtica species have flowers on their stems, that don't look like a typical flower. I've pulled out patches of Urtica dioica with my bare hands and the pain subsided within an hour, but I had a prolonged period of slight numbness where I touched it. There is a west coast noseburn species Tragia ramosa,

that has a painful sting? It appears to stay restricted to California. It would have a more conventional type of flower.

https://en.wikipedia.org/wiki/Dendrocnide_moroides#

Sensitivity to contact dermatitis originating from these sorts of plants will vary by individual. Some will have a much stronger and/or longer lasting reaction than others. I've worked with a large assortment of plants almost my entire professional life and luckily have yet to encounter a strong reaction to any of the most common reactive ones. A nettle sting is only a minor and very temporary sensation for me. Yet my daughter has a permanent blemish on her inner arm from contact with rue, Ruta graveolens. I could bury myself in rue and it would have no effect.

thefof - I was responding to morz8’s post, not the OP.

A 4-5’ tall plant that stings is rare.