autumn berries berry bush coastal Elaeagnaceae fall fruit Hippophae rhamnoides maritime natural nature orange plant sea buckthorn shrub spiny wild black castle defence defend defense fort fortress gray grey medieval moat palace security sky storm stormy wall walls war white bank brassicaceae Crambe maritima Cruciferae Cuckmere Haven ecology England english gravel Great Britain habitat halophyte halophytic sea kale shingle stones summer landscape plants cliff coastline