Brahea armata

Brahea armata 
Above - a marginally hardy palm in the UK. If given a hot, sunny position it will grow quickly, which is as important as surviving the cold; many borderline hardy palms that make it through the winter do not grow vigorously enough to really thrive. The 'Mexican Blue Palm' has the most silver leaves of any palm we can grow in the UK, and is hardy down to about -8c for short periods in well drained soil. Once established it is capable of producing 10 or more new leaves a year and after developing a substantial trunk may exceed even this. The spectacular flowers seen here on this fairly young plant growing in Naples Botanical Garden will probably never be seen outside of a Mediterranean climate.
Left - an older, spectacular specimen in Rome.