My miniature rose bush is still blooming. It is in a container and I have brought it in to my condo from the cottage and set it in a sunny window. What should I do to ensure it does well in the house over the winter?
Miniature roses in containers should not be fertilized past late summer, as the plants would likely send out new growth that is more vulnerable to winter damage. Trim off dead/wilting flowers and get rid of plant debris. Reduce watering – the bush should go dormant.
Instead of bringing your plant into a warm, light room (as you have done) – which will prevent dormancy – move it to a garage, shed or basement for the winter. The temperature should be between 25-50 degrees Fahrenheit (-3 to +10 degrees Celsius). If the room is particularly cold, you can wrap the plant and its container in a blanket and prop it up on bricks so it does not touch the cold cement floor. Prune the plant back to the shape you want, or just trim individual stems, if you wish Do not permit the soil to dry out completely – keep it slightly moist throughout the winter – check the soil every 3 weeks or so.
The plant should start to come out of dormancy in the spring, which means that it is time for it to be placed outside – each day, leave it outside for a little longer, so it gets accustomed to the outdoors (this is called hardening off). If there is a late spring freeze, you can bring the plant back indoors or cover it with a blanket.