Plant of the month: April - Puya chilensis
Puya is a genus of over 160 species, the majority of which are to be found on the mountains and foothills of the Andes. They are bromeliads but not the epiphytic, tree-hugging sort but terrestrials, with strong root systems buried in the earth. The basic form of these species is a large rosette of slender, pale green, blade-like leaves, which make for a plant both striking and graceful. Over the years they form extensive clumps, spreading along the contours of the land, the rosettes standing up to 2m high.
Puya chilensis was first introduced on Tresco in 1848 and was planted on a terraced bank in the middle of the garden. It now occupies, to the exclusion of all vegetation except the wily bramble, a commanding site over 30m long and 8 m deep. This thick swathe of puya has inched its way down the bank over the past 154 years, leaving behind it snaking trails of stout brown trunks.
Each spring the clumps of puyas send up great spikes of flowers 2-3m high, the flowers clustered at the top. The actual flowerhead is about 1m long and packed with racemes of chunky flowers, the sterile tips of which stick out, affording a perch for thirsty birds. In silhouette, the ensemble is akin to a medieval mace. The individual waxy blooms are 6-8cms long, providing a deep receptacle for the nectar that the birds, bees and even some gardeners find so compelling.