Complex sentence: Plans for the garden were cut short as the family suffered severe financial losses when their agent went bankrupt, although many of the North American plants were planted and flowered for the first time in Great Britain.
Split into simpler sentences: Plans for the garden were cut short as the family suffered severe financial losses when their agent went bankrupt. Although the garden was not completed, many of the North American plants were planted there and flowered for the first time in Great Britain.