Puya coerulea var monteroana, Chagualillo, is an intraspecific taxon of Puya coerulea from Talca Province, south of Santiago where it grows on rocky arid slopes up to elevations of 1500-2000m. It forms low clumping colonies with glaucous blue arching foliage that are thin and linear and from a distance resemble clumps of blue-ish grass. Its multi-branched inflorescence rises to 2m and has dark violet flowers with three petals, yellow anthers and a green stigma.

Like all Puyas it requires perfect drainage and a dry regime during the winter. The Chilean Puyas are more of a challenge in UK conditions than the tougher somewhat more hardy Puyas from Argentina and will require a very favoured southern microclimate together with winter protection. In such a location, a near-vertical rocky wall facing south with some overhanging evergreen foliage is as perfect as it gets. The safe but sure option is to grow it in a container and bring it in to the conservatory for the winter.