An exotic garden cannot exist without palm trees. The easiest one is Trachycarpus fortunei. It thrives in relatively cool summers, but needs some protection during extreme frosts with hessian or straw. Good draining soil is important. A good Trachy has stiff leaves, there are however many inferior plants in the trade. Trachycarpus princeps with blueish leaves is a must-have, but less hardy than T. fortunei. The hardiest feather leaved palm is Jubaea chilensis, in zone 8 climates and lower this beauty needs shelter from cold weather in winter; it can survive -12°C for a short period. Some hardy Butia's like B. eriospatha and B. capitata can be grown succesfully in mild climates (zone 8b and higher).