How To Winterize Your Roses
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To winter protect (winterize) your roses simply means to give them added insulation (mulch, straw, etc.) around the base of the plant after they have experienced a prolonged freeze that induces dormancy. The purpose of this is to protect them from warm spells during the cold months that could promote growth. The following will help ease the transition from active growing to dormancy.
- Stop fertilizing roses after the first part of August: Fertilization stimulates growth, and new growth damaged by a sudden temperature drop can place undue stress on the rose. Roses need to slow their growth rate for dormancy purposes.
- Discontinue deadheading in August: When spent flower heads turn into rose hips, it is a sign that the plant is preparing for dormancy.
- Have a healthy and disease-free bush during the summer: A healthy rose has a better chance of surviving a harsh winter than one with constant issues.
This is the hard part: What kind of roses do you have? Grafted roses are the most tender because the graft (also called the bud union) is temperature sensitive. If the rose dies back to the graft, but the roots are alive, it will send shoots up to grow a new, different rose bush. Begin using insulating materials after the rose has gone dormant. Depending on your location, this could be anywhere from September to the end of November. If you have had at least 2 hard frosts below 25 degrees, the rose should show signs of dormancy.
- Mulch: For tender roses, using a rose collar helps to hold the mulch in place and keep out hungry critters like rabbits. On tender roses, add mulch up to 12", because in Colorado, we have dry air, especially in winter. We also have extreme temperature fluctuations in early spring. From winter into spring is the period when roses suffer the most damage.
- Water your roses during the winter at least once a month: When temperatures allow. If snow is on the ground, don’t water.
- Do not remove protection too early in the spring: Late season freezes can kill tender new growth or blacken canes stimulated to grow by recent pruning.
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