In July 1858 he joined the National Rose Society, which Samuel Reynolds Hole had just founded, and in 1866 he was one of the executive committee of twenty-one members for the major International Horticultural Exhibition.
In addition to The Rose Annual, which he issued from 1858 to 1881, Paul was associated with his friends Dr. Robert Hogg and Thomas Moore in the editorship of The Florist and Pomologist from 1868 to 1874.
The library of old gardening books and general literature, which he collected at his residence Waltham House, was sold at Sotheby's after his death, but many volumes were bought by his son.
He then helped John Lindley for whom in 1843, he wrote articles in the Gardeners' Chronicle on "Roses in Pots",' which were issued separately the same year, and reached a ninth edition in 1908.
[1] Although best known as a rosarian, Paul devoted attention to the improvement of other plants, such as hollyhocks, asters, hyacinths, phloxes, camellias, zonal pelargoniums, hollies, ivies, shrubs, fruit-trees, and Brussels sprouts.
He dealt with these subjects in American Plants, their History and Culture (1858), the Lecture on the Hyacinth (1864), and papers on An Hour with the Hollyhock (1851) and on Tree Scenery (1870–2).