Streifzug means ‘foray,’ ‘ brief survey,’ or ‘ramble’ (if my online German/English dictionary does not deceive me).
These photos are from yesterday’s ramble or, more specifically, bike ride.
The sign says, “Only paid-for flowers make friends*/joy.” Sonnenblumen are sunflowers. These are not quite open yet.

Blumen Selbt Schneiden or ‘cut your own flowers’ signs — with honor-system money boxes — are not uncommon sights alongside fields in the Stuttgart area. These long rows were beside a walking/biking/farm access path near our neighborhood.
(On the same ride, I also passed a house with a sidewalk shelf of already cut flowers in jars and a coin box.)

The fields around the rows of cut-your-own flowers are filled with wheat, beans, corn, and grass for hay.

Also, as you can see, our weather has much improved since Wednesday. Temperatures are now well into the seventies.
*See the comments here about the translation.
maybe this?
http://theseedsite.co.uk/profile410.html
Phacelia tanacetifolia
Purple Tansy
This does look a lot like them.
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