Puya - Growing Guide
Growing Puya
Only once in 30 years have we managed to exhibit a huge flowering spike of this extraordinary plant. Even then the flower spike came from Tresco in the Isles of Scilly. Since puya flower only once in their lifetime before the plant dies, and you may have to wait up to 30 years or more for this to occur, you can see the problem with exhibiting this plant at any show!
These plants will only grow outside in the warmest, hottest and driest coastal locations with any chance of flowering but flower outside they do in Penzance, Falmouth and at Ventnor Botanic Gardens in the Isle of Wight. The two species of this bromeliad from the rocky slopes of the high Andes in South America which are most likely to succeed in coastal western gardens are P. berteroniana (blue-green flowers) and P. chilensis (yellow-green flowers).
Puya have rosettes of upright light green leaves becoming more outspread with age. In maturity these can be at least 30in long with nasty barbs. For a plant to be mature enough to be capable of flowering it needs to be 4-5ft across. Then a huge trunk will emerge topped by a huge 3ft cluster of numerous flowers in loosely branched panicles. After flowering the flower head, and indeed the whole plant, dies off after the exceptional effort of producing such a vast flower spike. There will however be many offset plants around the base or in the clump which the flower emerged from and the seed are easily germinated if sown in the autumn or spring in a frost free greenhouse.
Puya will tolerate a few degrees of frost with no ill effect but they are really greenhouse plants best grown not in pots but in an open and upraised bed. Waterlogging and over watering is the quickest way to kill these succulent plants. At Renshaw gardens near Sheffield puyas are doing well in a warm conservatory set against a well drained sunny wall. If growing them outside they need to be on a raised bank in full sun but with wind protection.
Even if you never manage to flower your puya the foliage effect is good enough. If you can grow yuccas and agaves successfully you can probably attempt puya outside too.