"An Orangery was a building requently found in the grounds of fashionable
residences from the 17th to the 19th century. Similar to a greenhouse or conservatory.The name is derived from the original use of the building as a place where citrus trees were often grown in tubs and wintered under cover. The orangery originated from the Renaissance gardens of Italy, when glass-making technology enabled sufficient expanses of clear glass to be produced."
One of the renowned orangerie is The Orangerie of Versailles (France). Most of the trees there are in huge jars that are moved inside during winter. There are really lemon and orange trees there.