• Conservatories can help gardeners in cold climates grow plants that may not survive outdoors.conservatory image by Hilma Anderson from Fotolia.com
  
  A cold conservatory, which is an unheated greenhouse typically made of glass, helps you raise plants that normally could not grow in your USDA hardiness zone. Because the conservatory can be 10 to 20 degrees warmer than outside, plants from up to two warmer USDA zones can thrive. Monitor inside temperatures using a digital thermometer that registers both high and low temperatures over a 24-hour period.
  
  

Camellia

• Camellia flowers are lovely floated on top of water in a glass or bowl.camellia caught by light image by feisty from Fotolia.com
  
  There are more than 800 varieties of camellias, with flowers in a wide range of colors including white, pink and red. The flowers can be single or double. There are many new cold-hardy camellia varieties. Some are hardy down to USDA hardiness zone 6, where the average minimum temperature is -10 to 0 degrees Fahrenheit. The problem with many of these cold-hardy varieties is they set their buds, but instead flowering in the winter, the buds simply fall off.
  
  Growing regular camellias in pots in a cold conservatory can solve this problem by allowing your to use a less-hardy variety for your zone.
  
  

Gardenia

• Gardenias bloom inside a cold conservatory during the winter months.gardenia image by Igor Zhorov from Fotolia.com
  
  Gardenia thunbergia, an African native, is hardy to USDA hardiness zone 8a, where the average minimum temperature is 10 degrees Fahrenheit. It prefers acidic soils, similar to camellia. Although many gardeners in cooler climates could grow gardenias outdoors, choosing these as plants for pots in a cold conservatory makes more sense. The white fragrant blooms will last longer under glass and not sustain the damage they would outdoors. Gardenias can be trained into a small bush or a tree form. They can be grown in full sun, but do better if they are given some shade during the hottest part of the day.
  
  

Musa Basjoo

• A banana flower with fruit forming on it.banana tree image by naolin from Fotolia.com
  
  Musa basjoo is a banana plant hardy to USDA hardiness zone 5, where the average minimum temperature is -20 degrees Fahrenheit. This banana is a great choice for plants for pots in a cold conservatory. Protected from frost and severe weather elements, musa bajoo is more likely to bloom in a cold conservatory than outside in colder climates because the plant will not die all the way back in the winter. The fruit from musa basjoo will be full of seeds, so the variety is not grown for eating.