Most modern roses need protection to survive the cold winter months in Iowa. Hybrid tea, grandiflora, and floribunda, as well as some polyantha, miniature, and climbing roses, are not reliably winter hardy and must be protected.
Most shrub, landscape, species, and old garden roses, as well as some miniature, polyantha, and climbing roses, are reliably winter hardy and do not require extensive preparation for winter.
The process for preparing roses for winter is outlined below.
Most hybrid tea, grandiflora, floribunda, and other modern roses require protection during the winter months. Low temperatures and rapid temperature changes in winter can severely injure and sometimes kill unprotected modern roses. Modern roses are typically grafted. This graft union is particularly sensitive to cold temperatures and requires protection over the winter months.
Hilling or mounding soil over the base of each plant is an excellent way to protect these roses.
- Begin in late fall (mid-November) by removing fallen leaves and other debris from around each plant. Removal of diseased plant debris will help reduce disease problems next season.
- Loosely tie the canes together with twine to make working around the plants easier and prevent the canes from being whipped by strong winds.
- Cover the bottom 10 to 12 inches of the rose canes with soil.
- Place additional material, such as straw or leaves, over the mound of soil. Typically 1 to 2 feet of material loosely packed is sufficient. A small amount of soil placed over the straw or leaves should hold these materials in place. Alternatively, wire fencing can hold the loose mulch material in place.
- Skip the styrofoam cones. It is difficult to fit the large rose plants inside the cone with enough insulating material without extensive pruning (which should not be done in the fall months). These cones can also get very warm on a sunny winter day. This drastic swing in temperatures will cause more winter damage.
Remove all overwintering materials after the group thaws in the spring - typically sometime between mid-March and early April in Iowa.
Most shrub, landscape, species, and old garden roses are winter hardy and require no additional work to survive the winters in Iowa. Even these winter hardy roses will see some tip die-back from cold temperatures in some years.
While not required, these roses can be provided winter protection to reduce the potential of winter die-back or damage.
- In mid to late November, put a wire cylinder around the plant. Carefully tie up canes if needed.
- Place 3 to 4 feet of straw or pine straw in a wire cylinder.
- Remove the winter mulch in mid-March before the plants break dormancy but after the harsh cold temperatures of winter have passed.
Miniature roses are fully or partially winter-hardy in Iowa, depending on the cultivar. In most years, most miniature roses can survive without extensive winter protection. To ensure survival over the winter, partially cover miniature roses in late fall (mid-November). Place soil at the base of the plant, followed by a covering of straw or leaves. Plants can be smothered if they are covered completely. Uncover plants in late spring (mid-March).
Miniature Roses in Containers
A potted miniature rose can be kept as a houseplant through the winter months. Bring the plant indoors before a hard freeze. Place the miniature rose in a sunny window or under artificial lighting. Avoid sites near cold drafts or heat sources. Water the plant when the soil surface becomes dry to the touch. Apply a dilute fertilizer solution every 2 to 4 weeks through the fall and winter months.
Another option would be to over-winter the miniature rose outdoors.
- In early November, dig a hole in a protected garden location.
- Place the potted rose in the hole. Then place soil around the pot.
- Several days later, cover the bottom 8 to 10 inches of the rose with additional soil. The soil should remain in place through the winter months.
- In early April, remove the soil around the canes, carefully dig up the potted rose, and prune out any dead wood.
- At this time, the dormant rose could be planted into the ground or repotted into a slightly larger container.
Most climbing roses are not reliably winter-hardy in Iowa. Because they are not fully winter-hardy, climbers can sometimes see extensive winter dieback, negatively impacting flowering and greatly reducing their size. A few cultivars are reliably hardy and flower well most years in Iowa. For these roses, no winter protection is required.
The overwintering process is more labor-intensive for those climbing roses that are not reliably winter hardy. To protect these plants from the harsh winter temperatures, the entire plant must be covered with soil.
- In late autumn (early to mid-November), remove the rose from its trellis or climbing structure.
- Carefully bend the canes to the ground.
- Gently pin the rose down and cover the canes with several inches of soil and a layer of mulch.
Climbing roses can be uncovered with all other roses in early spring (mid-March).
Tree roses are modern roses, such as hybrid tea, grandiflora, and floribunda types, grafted to a tall stem. Protecting these roses is more labor intensive than other rose types because the graft union (sensitive to low winter temperatures) is positioned high up on the trunk.
- In late fall (early to mid-November), dig the root ball out on one side of the plant by removing a semi-circle of soil about 12 to 18" from the base of the trunk.
- Bend the entire plant down to the ground level in the opposite direction allowing part of the root ball to rise out of the ground and leaving the other half undisturbed.
- Secure the plant on its side with wooden stakes, landscape staples, or wire pins.
- Cover the partially exposed root ball, trunk, and all the stems with 10 to 12 inches of soil.
- Place 1 to 2 feet of additional material, such as straw or leaves, over the mound of soil. Wire mesh fencing or a small amount of soil placed over the straw or leaves should hold these materials in place.
Remove the mulch and soil in early spring (mid-March) and replant the tree upright.
Tree Roses in Containers
Tree roses growing in pots or other containers also need winter protection. One method is to dig a trench in the garden, lay the potted tree rose in the trench, then cover it with several inches of soil. Another method would be to place the potted tree rose in a cool garage or shed. Temperatures in the storage area should be consistently in the 30s and lower 40s°F. Learn more about overwintering plants in this article: How to Overwinter Plants
A rose growing in a pot may be destroyed if the potted rose is left on a deck or patio over winter. Potting soil temperatures in containers left above ground are likely to get extremely cold, damaging or destroying the roots of the rose.
To protect a potted rose:
- Dig a hole in the ground in a sheltered location in late autumn before the ground freezes but after the plant has gone dormant (mid to late November).
- Set the pot in the ground and then place soil around the pot.
- Place additional soil over the rose covering the bottom 6 to 8 inches of the rose canes.
- Place 1 to 2 feet of straw or pine straw in a wire cylinder wrapped around the plant.
Remove the winter mulch and excess soil and pull the container from the ground in mid-March before the plants break dormancy but after the harsh cold temperatures of winter have passed.
Containerized roses can also be overwintered as dormant plants in a cool protected location such as a cool garage or shed. Temperatures in the storage area should be consistently between 30 and 45°F. Learn more about overwintering plants in this article: How to Overwinter Plants.
- All About Roses
- Growing Roses in Iowa
- Rose Types and Cultivars for Iowa
- A Brief History of the Rose
- How to Select and Use Roses in the Garden
- How to Prune Roses
- How to Plant and Transplant Roses in Iowa
- How to Propagate Roses
- Pests and Disease of Roses
- Rose FAQs
- Caring for Roses in Iowa (publication)
- Miniature Roses (publication)
- The Griffith Buck Roses (publication)
- Griffith Buck: Rose Hybridizer (publication)
- Roses for the Home (publication)
- Common Rose Diseases (publication)
- Gardening in the Zone: Winter Rose Protection (video)
- How to Overwinter Plants
- How to Protect Trees and Shrubs from Animal Damage Over Winter
- Flowers and Their Meanings: The Language of Flowers
- State Flower of Iowa