Agave franzosinii syn. Agave beauleriana better known as the Blue Agave is a very large, striking agave with glaucous, light grey-blue leaves which curve at the top gracefully. Of unknown origin and not found in the wild Agave franzosinii is most probably a form or hybrid of Agave americana, being similar but much more blue than most other of the agaves and as such very sought after amongst collectors. Should be hardy to at least minus 5 degrees centigrade but as with all agave must be very dry during periods of cold.
If you want to try growing year round outside choose a hot sunny position with perfect drainage, add gravel and ideally mulch around the base with gravel too. I always recommend building a roof over the top of treasured agave plants in winter. Simply hammer in 4 stakes around the agave a fix a clear plastic ‘roof’ onto the top of each stake above the agave leaving the sides clear allowing wind to pass through the leaves. Alternately we recommend growing in a pot in full sun from April to the end of October depending on the weather and moving it to a greenhouse, conservatory or even shed for the winter where it can have protection from freezing and wet. No watering will be needed from November to March.