Agave montana, the mountain agave is one of my favourite easy to grow agaves from mountainous regions of Mexico where naturally conditions are harsh. Often experiencing freezing tempauratures and moist conditions Agave montana is a great candidate for outdoor cultivation here in the U.K. With superb architectural rosettes of deep green broad leaves pale creamy marginal thorns and pinkish red terminal spines this is a special agave tolerant of temperatures down to minus 10 degrees.
As with all of the hardier agaves 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.