Caring for roses in the Fall
The annual change in Fall weather can bring windy and rainy conditions into our beloved rose gardens.
The widespread appearance of diseases like black spot and powdery mildew provide a reminder that next year’s success depends on getting back into the garden to prepare the roses for surviving the harsh environment until then.
Here are the 8 Fall chores to focus on in Puget Sound rose gardens that help ensure a strong & healthy start in the Spring – whenever that occurs.
1. Stop deadheading 2 weeks before Halloween
This will harden off the roses, allowing any tender new growth time to toughen prior to a possible damaging cold snap. If your roses have hips, allow them to develop naturally. You’ll be rewarded with seasonal color & texture – plus the birds will love you for the cold weather treats.
2. End the fertilizing and transplanting
Fall marks the end of stimulating the plant, so prior to the onset of cold weather don’t add nutrients to your bushes. This will prevent the rose from pushing out any new growth at the wrong time of year. This principle is true of moving a bush as well since the small roots will want to grow quickly into their new soil, thus stimulating new growth – but it’s the wrong time of year underground too.
3. Clip off diseased leaves
Find and trim the diseased foliage from the bush with sharpened shears. Pulling leaves off by hand can create small tears along the stem and provide an entry point for disease, so use the tools.
Use a disinfectant like Lysol aerosol spray on your pruners between bushes, as well, to reduce the chances of spreading pathogens yourself.
This important chore reduces the host environments for black spot, powdery mildew, rust, & other diseases that survive the colder temperatures on your bushes this winter.
4. Deadhead the remaining failed buds
Trim the smaller & failed buds that did not open due to our famous rainy conditions. This will help reduce the chances of growing Botrytis cinerea, a fungus that attacks tender blooms in the presence of high humidity. In rosarian terms, this chore is called “balling” to avoid gray mold. (I’ll spare you that picture.)
5. Rake up and destroy all garden debris around the bushes
After your trimming & pruning, rake up all the clippings and leaves around the bases of your rose bushes and other nearby plants. Do not compost these, as this could spread the pathogens that you have probably trimmed off. Just send them off to the dump.
Many gardeners follow through with a spray program of either horticultural oils or sulfur solutions (not both), which are available at your garden center. These sprays can be applied monthly throughout autumn and winter as long as the temperature stays above 45 degrees Fahrenheit. Both sprays also kill overwintered eggs from aphids, spider mites and other garden pests.
Since many fungal diseases and pests that affect roses overwinter in the litter on the ground, removing as much of this material as possible will reduce a wide variety of problems next spring.
6. Cut your tall roses to 4 feet
Top off taller hybrid teas, floribundas, grandifloras, or even shrub roses at 4 feet to reduce the risk of wind whip. In colder micro-climates, the combination of the wind with wet freeze/thaw cycles can even uproot the entire rose bush from the ground.
Also look for crossed or thin canes that can whip individually against each other, causing cane wounds from rubbing or thorns. Remove these offenders as needed.
7. Protect your climbing roses
This is the time to prune off the bushy overgrowth on climbing roses and tie large canes securely to structures to reduce the chances of any top-heavy canes breaking in the wind.
It’s also a good time to retrain your vertical canes more to the horizontal for increased bloom growth next spring as well.
Bloom growth on climbers happens 80% on these horizontally oriented canes, so this makes quite a difference.
8. Add mulch
Mulching with quality compost or or other clean mulches around the base of the roses provides valuable nutrients – as well as an insulating layer that will protect roses during cold snaps. A 3- inch layer is sufficient in most lowland areas here in Puget Sound, but in cold & snowy micro-climates like North Bend or Ashford, make a compost mound around the crown & base of your roses for even more insulating.
It is not winter’s simple cold that kills roses, but the roller-coaster weather patterns.
In spring, plan on spreading the mulch out into the bed, away from the base of the plant to add nutrition to the entire garden’s soil.
Fall’s great 8
Even the metropolitan horticulturists I work with in community gardens in Puget Sound follow these practices, and thousands of happy visitors are proof that the effort pays off.
So, lf you can manage our Fall weather, these 8 great habits will yield show-winning blooms from your own happy rose garden too.