Garden Mastery Tips
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October 2007 |
Preparing Roses for Winter
Fall is a critical time for perpetuating the health of roses. A few simple steps will ensure plant vitality for the next spring.
Let's review the proper winterizing sequence:
Stop fertilizing 6 weeks before the first frost is expected.
Allow the blooms to go full cycle on the bush. Let them drop their petals and form hips or seedpods. While hips form, a hormone is being released that tells the bush to stop blooming and to get ready for dormancy.
Resist the temptation to deadhead (remove spent blossoms) or cut back your plants at this time. The vitality of the bush remains in the canes and foliage. A couple of hard freezes (generally accepted as an overnight low of 28 degrees) will cause the vitality of the plant to go down into the root system where it winters, ready to burst forth in the spring.
After a few hard freezes, prune all bushes except climbers, large shrubs, old garden roses (OGR) and standards (tree roses) back to about 2 feet high. Shortening the bushes keeps the canes from whipping in the wind and prevents root system damage. Severe or prolonged rocking in the wind can injure or kill a plant.
OGRs and shrub roses can be cut back with size, shape and condition of the plant as your guide. You will usually remove no more than 1/3 of the plant.
Strip remaining foliage. Prune out dead, damaged or diseased canes. Remove twiggy side growth from canes and clean out all debris from around the base of the bush. Place all materials removed from roses in yard debris for recycling and not in garden compost bins. Most small garden composting does not reach high enough temperatures to kill fungal disease spores or insect pests that damage roses. Also, cut off any suckers (canes that grow from below the bud union).
Spray canes and ground around each bush with a dormant spray. This is more important than spraying in the spring, especially if you had a lot of blackspot or powdery mildew.
Sprinkle a cup of lime around each plant to help keep the soil pH at an optimum level. Most roses do best in the 6.0 to 6.5 range. Lime also helps counteract the acidifying effect of the salts in most commercial fertilizers.
Remove old mulch and replace with new disease- and pest-free material. This aids roses to get a fresh and energetic start in the spring. Mound up mulch 6 to 9 inches around the canes, being certain to completely cover the bud union. Don't take the soil from between the bushes. You will now have taken the two most important steps to protect roses from the cold. The mound of mulch protects the bud union from freezing and the mulch keeps the canes moderately protected so they won't start throwing new growth during winter warm spells.
Monitor soil moisture and condition, watering as necessary, or until ground freezes and remains frozen.
Defer any additional pruning until late February or early March.