Question
QUESTION: I purchased 58 roses this year but was not able to get all areas ready for their planting. It is early November now and putting them in the ground in their pots and mulching after hard frost is risky. I have a greenhouse to keep them humid and 50+ degrees all winter. Is this the better route? They will not go dormant at all then. Collection has hybrid teas, rugosas, floribundas, species, Old English,etc.

Thank you.
Tim Copeland

ANSWER: Roses need a dormant period to do their best and the winter killing of their leaves gives them that rest period. If you keep them in a heated warm and humid greenhouse, they will not go dormant and the growth will be weak. In the spring before you plant them in the garden, you will have to remove the weak growth before planting them. The ideal would be to keep them just above freezing so they go dormant and therefore be stronger in the spring.I don't know where you garden, but if there is no hard killing frost for a couple of weeks, I would at least plant the Species, Austins and Rugosas in the garden and then mound the bush up with compost, soil or mulch to 8 inches and that will make sure they go through the winter without being killed. The best time to mulch any rose is after there has been a couple of hard frosts and then you know for sure the rose is dormant and the protective mulch will not activate any growth.

---------- FOLLOW-UP ----------

QUESTION: Thank you. I am in St Louis, Missouri (zone 5) The Greenhouse is 12X8 ft and 9 1/2 ft tall. I use it for tropicals; veggies/annuals that I start early in Jan; and select specimen annual/delicates that I keep. I have purchased a halide light and can probably get it installed in a couple of weeks. Would this additional light keep the growth strong enough not to weaken? I could do as you have said and place them in the garage after several hard frosts with a small space heater when temps get below 20. Which would be better?
Thank you very much.
Tim C.

Answer
Greenhouses are ideal for the tender roses such as teas and noisettes, but in your climate you need hardier ones such as those you have purchased. These types do best when they get a dormant period. The growth that is activated in the greenhouse will never be as strong as outside even with a halide light. These lights activate growth and are excellent for annuals, tropicals etc but not for hardy shrubs, which is what a rose is. I am not saying it won't work but just be very careful when you put the roses outside as they will not have strong growth and a cold wind could cause some dieback. I wouldn't plant them in the garden until the weather is totally free from any frosts. Zone 5 is ideal for growing the types of roses you got and they will go through the winter without any problems. If you want to place them in an unheated garage, just make sure you wrap them in something like bubble wrap and make sure their roots never dry out. Spraying them with water once a month will ensure that they don't. Roses roots are activated into growth when the temperature goes above 40' so anything below that keeps them dormant. Because they are dormant, they will not need any light.
However in a perfect world, the ideal answer to your problem is to dig a large hole in the garden, tie the roses up in a bundle and plant them in the hole and then cover them with soil or a mulch so that just the tips of the canes are sticking out. They would be fine and survive the winter well. Failing that I would say the greenhouse and simply make sure that the weather is warm enough so  the tender new growth will not suffer. I too have ordered over a 100 new roses and because they came too late, have had to put them into holes in the garden. I would have preferred to plant them now.