Woodland sunflower Helianthus decapetalus . Helianthus decapetalus, also known as the thinleaf sunflower or forest sunflower, is a native North American perennial wildflower in the Asteraceae family

Helianthus divaricatus, Woodland Sunflower. Note the rough leaves that are sessile. The app focused on the ray floret count, which matches petal count of decapetalus.

I did note that the petal count varies considerably at the various web sites that I checked for information. I presume that your reference to "The app" is suggesting that Celery may have used such to make that recommendation. Thanks for the input.

I didn't need an app, but I tried google lens with them and more suggestions for Helianthus divaricatus were given for the pic showing leaves. The flower pic got several different species as suggestions, but divaricatus was one of them. I think I noticed the variation in the ray petal count which ranges about between 8-20 petals. Helianthus strumosus and Helianthus hirsutus look very similar but both species have short leaf petals whereas the leaves of divaricatis are sessile. Rough Leaved Woodland Sunflower is a good name to distinguish it from other Helianthus species with the commin name Woodland Sunflower. Plant apps can be useful. There are thousands of yellow composites. If a flower seems to match, you still need to check the folliage for leaf arrangement, petiole shape and length, leaf shape, leaf texture, surface, pubescence, tip shape, base shape, angle leaves appear, 90%, juxtapised, in a straight plane or whorled pattern. Also the habit, multiple or single stem, branches, upright, prostrate, decumbent, vining?

Thank you for using living plants in situ!

Thanks for the enlightening response. I had to look up some of those words, but hey, that's how one graduates from one level of knowledge to the next.

I "rescued" some Jerusalem Artichoke tubers from a country roadside and my original 6 foot row of 8 tubers has now spread out to about 10 feet long and 6 feet wide, it's now at full bloom. The original colony along the road is gradually getting overgrown with grasses and shrubs.

Sawtooth Sunflower, Helianthus grosseserratus.

Western Sunflower, Helianthus occidentalis. I like it because it throws up a tall flower stalk from a leafy rosette, like Silphium species do. It wont thug out taller companions.

Ashy Sunflower, Helianthus mollis

It prefers to grow in sand. This is growing in a gravelly soil.

Hairy Sunflower, Helianthus hirsutus

Helianthus pauciflorus.

Maximilian's Sunflower, Helianthus maximiliani. I want to grow this species.

Willow Leaved Sunflower, Helianthus salicifolius. I've tried growing salicifolius seeds twice with no results. It's not locally native, but close enough.

These are not Helianthus but are very common sunflower-like plant natives found in local parks here. Most of these parks have restored meadows/prairies reclaimed from agricultural fields. I have so far been unsuccesful at getting them growing in my backyard. I've been getting my seed from commerical seed producers. Although, you never know, there might be some seedlings lurking in the undergrowth, I just haven't recognized them yet.

- Cup-plant, Silphium perfoliatum

- Compass-plant, Silphium laciniatum

- Prairie Dock/rosinweed, Silphium terebinthinaceum

Jay. I grew Helianthus maximiliani in the past, and it did reach maximiliani height. However once the fall rains came it flopped over, like dead. Not attractive at all. However by accident, I discovered it could be cut back before flowering(in August!) and it bloomed at a nice 3' height.