The British-English phrase everything in the garden is lovely, or rosy, means everything is satisfactory, all is well.
The Oxford English Dictionary (3rd edition, 2017) erroneously states that this phrase was first used in 1898 as the title and in the refrain of a music-hall song by John P. Harrington (1865-1939) and George Le Brunn (George Frederick Brunn – 1863-1905), written for, and popularised by, the British music-hall singer Marie Lloyd (Marie Alice Victoria Wood – 1870-1922).
In fact, everything in the garden is lovely already existed, as is clear from the column Many things in a few lines, in The Northern Daily Mail and South Durham Herald (Hartlepool, County Durham) of Thursday 22nd July 1897:
“Everything in the garden is lovely” (emphasis on the “lovely”) is London’s latest catchphrase. It has killed “Now we shan’t.” Lovely is the permanent Dublin adjective.
The phrase became popular in Scotland too, as mentioned in the column Glasgow gossip, in The Ardrossan & Saltcoats Herald (Ardrossan, Scotland) of Friday 30th July 1897:
It has come. The metropolitan successor to the all-pervading London catchword, “Now we shan’t be long,” has at last struck the city, and now we hear that “Everything in the garden’s lovely.” Emphasis on the “lovely,” please. Seems a trifle more idiotic than the now familiar phrase.
The author of the column Glasgow gossip of this newspaper expressed his dislike again on Friday 6th August of the same year:
Not to mention the fact that every other blattering jackass is engaged in calling your attention to the fact that “Everything in the garden’s lovely.” This, by the way, I find, is but an abbreviated version of the latest London catchword—“except the peas,” it seems, should be added. Which is certainly a crowning idiotic touch to a sufficiently fatuous phrase. Personally, I intend retaining allegiance to “Now we shan’t be long,” which occasionally, at least, sounded apposite.
Finally, the following is from the column To-day’s brevities, in The Greenock Telegraph and Clyde Shipping Gazette (Greenock, Scotland) of Thursday 5th August 1897:
The fireworks came off all right, and now, as the phrase goes, “everything in the garden is lovely.”
The earliest mentions of the song titled Everything in the Garden’s Lovely! that I have found date from Saturday 5th February 1898; for example, The Era (London) presented the programme of the newly rebuilt Metropolitan Theatre, on Edgware Road, London:
Miss Marie Lloyd, of course, forms one of the most potent attractions in the Metropolitan bill. Quite an original kind of song is “Everything in the garden is lovely,” and another successful song is about the gentleman who “Wants his presents back.”