- Generally, it is a good idea to stop fertilizing roses in early August. If you fertilize beyond that date, you can get a flush of new growth -- just when the plant should be winding down and preparing for winter dormancy.
- Also, stop deadheading (removing the spent blooms) in late summer. Instead, let those blooms stay intact and form seedpods, or "hips." The formation of hips signals the rose to stop growing. It's important that roses are in a full state of dormancy before the really cold weather hits.
- Once your roses are dormant, it is time to apply the winter protection. Begin by cleaning up the rose bed, removing all leaf litter from the ground and the top inch of mulch. There are many diseases that overwinter in leaf litter, so good housecleaning in the fall is essential. Some gardeners go as far as plucking off any leaves that are still clinging on the canes.
- Next, give the bed a deep watering. The roses need a big gulp before their long winter's nap.
Here are two options for protecting roses through long, hard winters:
- Cut canes back to 2 to 3 feet tall after they're dormant. Cover the crown with a 1-foot-deep layer of fresh bark mulch. The mulch will protect the crown and allow air to circulate. Donít use soil, leaves, or grass clippings as they tend to hold too much water, which can cause rot. Then wrap the canes with burlap to protect them from drying winds.
- Use purchased rose cones. Choose ones with an open top so the heat won't build up inside, and be sure to anchor them well so they won't blow away. These cost more, and it's not clear if they provide any better protection than the first method, but they are more convenient.
The main concern with tree roses is protecting the high graft. It is subject to more exposure to the wind and cold and drying than a graft buried underground and insulated by the soil. The standard method for overwintering a tree rose in northern climates is to dig a trench 12-18" deep in the garden. Then they dig up the tree rose, prune the top, and lay the tree rose into the trench and backfill it with soil. Mulch over top of the tree rose with organic mulch to provide some extra protection. Mark the area so you don't forget where to dig it up in the spring.
Another riskier option is to wrap the graft with an air-permeable material such as burlap stuffed with an insulating and non-packing material such as oak leaves. Plastic with insulation might be an alternative if you can vent it so that there is not excessive heat buildup on sunny days.
Another alternative is to dig up the plant and pot it once it's dormant, then keep it in a cold but nonfreezing location such as an unheated garage.
This shrub rose is very hardy and requires no special preparation for winter. Maintaining year-round mulch at two to three inches depth should be sufficient.
You have a few options come fall:
- You will have the best results by planting the rose with or without the pot in the ground and mulching it for the winter.
- Another option is to set the pot in a sheltered location, heap mulch over and around the pot to insulate the roots as best you can, and wrap the top with burlap.
- Get a piece of chicken wire, form a cylinder around the rose canes, and fill the chicken wire with straw or dried leaves. This will help insulate the branches from the cold. Water the plant thoroughly once before adding this protection, then it should be fine if it is in a protected spot out of direct sun. You might check the soil occasionally to be sure it hasn't dried out.
In any case, make sure to keep the soil slightly moist whenever it is not frozen, and it might make it through. It is very difficult to provide a rose with sufficient light indoors during the winter, so we donít recommend you bring it indoors.