The Brooklyn Botanical Garden produces an excellent series of publications on horticultural topics, and it is well worth joining for these alone, even if you have no intention of going anywhere near Brooklyn.
The most recent one deals with roof gardens, especially their beneficial contributions to energy management and improving building environments, and it's a good read.
Many good conservatories and gardens carry these in their gift store/bookshop.
May the long time sun shine upon you,
All love surround you,
And the pure light within you,
Guide your way on.