Simon Brett's Faber Book of Useful Verse is more than a collection of witty mnemonics, though it is at least that. An important point is raised in the introduction:

I make no apology for the large amount of material from the eighteenth century . . . at their best eighteenth-century poets demonstrated the supreme flexibility of blank verse and heroic couplets on any subject. There was good poetry and bad poetry, but there was not yet the distinction, on the grounds of subject matter, between 'Poetry' on the one hand and, on the other, the pejorative 'Verse'. It was the Romantic Movement (which has a lot to answer for in many ways) which changed all that.

This is well said (though it does not suggest why there was-relatively-so little 'useful' verse written in English before the eighteenth century) but the topic is not pursued. In fact the book is heavily weighted toward the lighter, funnier side of didactic poetry, and the many eighteenth-century pseudo-Virgilian agricultural and horticultural didactic poems are represented by a few fairly short extracts. Even these extracts seem chosen often for their (to post-Romantic eyes) bathetic junction of heroic style and mundane subject matter, rather than for the literary and didactic virtues the authors clearly hoped would recommend the poems. Thus we are given Cow-per's advice on growing cucumbers which begins with his-to us-unfortunate description of manure: 'The stable yields a stercoraceous heap/Impregnated with quick, fermenting salts', rather ...