Poem about weeds

[SOT3]

This is about a poem rather than a book but I couldn't think of where to post.

Years ago at school we were read a poem about the strength and tenacity of weeds which has always stayed with me. In adult life I have tried to google it many times to try to find it but it must not have 'Weed' in the title of the poem as I can't find it.

I just wondered if anyone has come accross this poem and could help me find it please?

U.A.Fanthorpe wrote one called "Under the Motorway". It's about the seeds that make the weeds. Possible?

Last verse of "Under the Motorway" :-

On viaduct, bypass, clearway, trunk,
Mercedes, Minis turn to junk.
But Love-in-a-Mist and Love-lies-Bleeding--
They're on our side, and they're succeeding.
Rolls Royce and Volvo, their day is done,
But Charlock and Dandelion blaze in the sun.