This card may have stumped you but it does have a very strong Derbyshire connection, for this is Jacobs Ladder, their county flower, also known as Polemonium Caeruleum. Polemoniaceae is actually the family name for a group of plants often better known as phlox, whilst the Caeruleum means blue, referring to the fact that the flowers come in shades that vary from deep blue to soft lavender, sometimes tinged with white. .
As far as its non-biological name, Jacob’s Ladder, it is usually quoted that an early plant historian looked at the plant and the parallel, step like arrangement in the sections of each leaf suddenly reminded them of the part in the Bible when Jacob dreamed of a ladder into heaven. Or perhaps it was actually named in this way by someone who tended the gardens in a local medieval church or other religious establishment. This is made even more possible by the fact that it has several medical uses, for stopping the bleeding of wounds, and healing or relieving toothache, coughs, fevers, insomnia, tuberculosis, insomnia and animal bites. It was also used as a sedative, including for minor operations.
We do not know why it was selected to be the Derbyshire county flower, but it does seem to grow better there than anywhere else in the country. And you may think it strange, then, that it is not on the Derbyshire County Flag - that honour going to a Tudor rose, in style if not in colour, for this rose, which has been the official county badge ever since the 15th century, is gold, perhaps so as not to take sides between the Yorkists and the Lancastrians, whose counties were close neighbours.
R. & J. Lea were founded in 1865, and as this card states, they were in Manchester, specifically at 45 Market St, and Broughton Lane. It was only later that they relocated to Stockport.
Without a special reference book devoted to the company and their cards, we have only their listings in the World Tobacco Issues Indexes. The original one reads simply : "FLOWERS TO GROW. Sm. Nd. (50)", whilst the updated version adds a bit, namely : "FLOWERS TO GROW. Sm. Subtitled "The Best Perennials" Nd. (50)"