Question: I brought my miniature rose indoors and it is blooming. A friend told me I shouldn’t let it bloom and it should be dormant. What should I do? P.P.
Answer: Your miniature rose can be grown indoors as a houseplant during the winter. Miniature roses need at least 5 to 6 hours of direct sunlight per day. Daytime temperatures around 70 degrees and night temperatures above 60 degrees are best. Water when the top inch of potting soil is dry. Fertilize every two to five weeks when in bloom. I think this year I’d let it grow as a houseplant. I don’t know if you can successfully get it to go into dormancy. You can try to stimulate dormancy by reducing water, leaving the dead flowers, and moving to the cooler room. If growth slows and the leaves drop, move the plant an unheated room. Let the rose remain dormant for the rest of winter.
Regardless of the way it spends winter, move your rose back outdoors in early May. You can leave it in the pot or plant in the garden.
Miniature roses may look delicate but most are reliably cold hardy in southeast Wisconsin. The easiest way to grow hardy miniature roses is to treat them like regular roses. In other words, plant them in the ground and leave them there. To insure your miniature rose survives the winter, partially cover it for the winter like other types of roses.
If your miniature rose is not winter hardy to zone 5, rosarians recommend storing miniature roses for winter in an unheated garage or room where the temperatures stay between 20 to 40 degrees Fahrenheit. If the miniature rose isn’t growing in a pot, dig it up from the garden in fall and transplant into a container with drainage holes in the bottom. Water it well, until water comes out of the drainage holes. Encourage the rose to go into dormancy by leaving spent flowers on the plant, reducing water, and not fertilizing. In January you can bring your miniature rose out of dormancy by moving it into a warm lighted room. Water and fertilize as directed above. Alternatively, you can keep your miniature rose dormant all winter and move it back outdoors in late April or early May.
Barb Larson is horticulture educator for Kenosha County University of Wisconsin Extension. Barb has a Master’s of Science in horticulture from the UW-Madison. If you have a plant or gardening question, email Larson at firstname.lastname@example.org or call her at 262-857-1945.