Roses need a four- to six-week dormancy period in winter months

Roses could still be seen actively growing and blooming in many area gardens following the Thanksgiving holiday, but believe it or not, roses need a four- to six-week rest or "dormancy" period during the winter months.

During dormancy, the plants go through natural hormonal changes that prepare them for the next growing season. Dormancy is triggered by a variety of factors. Cold temperatures (including frost) slow the plant's metabolism which helps bring on dormancy.

Rose growers can help by not deadheading or pruning this month. Allow the rose "hips" to mature so they can send signals to the plant that it's time to rest and marshal it energy for a vigorous growth spurt in the spring.

Just the same, be sure to monitor rose bushes when daytime temperatures are warm: they still need to be kept hydrated! Also, do not fertilize until after doing the major pruning in January or February.

On the topic of pruning: Some gardeners in this region are anxious to prune roses in December. That's understandable because we haven't had a hard frost yet, even though the average date for first frost in our area was last week. Pruning now not only prevents dormancy, but also produces tender new shoots that will most likely be killed by a hard frost. So, bottom line: Please wait four to six weeks after the first frost to do the major "spring" pruning.

By the way, I have just returned from the American Rose Society Pacific Southwest District Rose Show Convention held in Mesa, Arizona. Information was shared there that a new pest, the Asian "chili thrip," is spreading rapidly in the southwest and is becoming a global threat. This pest is extremely successful and particularly resistant to conventional control methods. I will provide more information as I receive it.