I have just been given a blue hydrangea in a pot and I don't know whether it should go in the garden or keep it in the warm. I think it was bought in a florist shop. Can you help me please?
Hydrangeas are perennial to zone 3 but some subtypes are only hardy to zone 5. If it is currently in bloom, I would enjoy the bloom indoors. Don't try to plant it out until your frost free date has past. At that point, spend up to a week getting it used to outdoor conditions. Start with putting it in the shade for several hours and daily increase the light level and amount of wind it experiences. There are several types of hydrangea; if the plant tag doesn't tell you the 2 word Latin name or its cultivar name, call the florist. That info is necessary to determine how to care for your shrub, particularly when and how to prune it. The blue color is only evident when grown in acidic soil. In alkaline soil, the bloom turns pink. There are garden sulphur additions for lowering soil pH. Test soil where the shrub will be planted to know how much to add. Use a fertilizer for acid-loving plants. https://www.gardeningknowhow.com/ornamental/shrubs/hydrangea/growing-hydrangeas-hydrangea-care-guide.htm