Rose Rhetoric: Good Advice, Bad Advice
by Rich Baer, Master Rosarian, Portland Rose Society
ABOVE: Photo by Rich Baer
When cooler weather begins settling over the rose garden with the potential for a light frost, rose gardeners begin seeking advice on how to ensure that their roses will continue to thrive. Unfortunately, the gardener may turn to sources which he or she has come to trust, which quite often may lead him or her astray. Your author, with almost 40 years of intensive rose training and two+ higher education degrees in botany, hopefully will lead you in the correct direction. It is not that the advice from the usual sources will cause irreparable harm, but often will cause some concern to you if you do not follow all of the suggestions completely. So, let’s look at some of the advice you may see that is, well shall we say, questionable.
One fact that seems to be missed by many rose experts is one that leads to incorrect advice about roses. This one fact that many experts seem unwilling to accept is that modern roses do not have the ability to become dormant. This is true of all repeat blooming modern roses. One time blooming Old Garden Roses have the ability to become dormant for the winter season and do so just like maple trees etc. Modern and repeat blooming roses sacrificed the ability to become dormant when they went through the genetic change that allows them to become re-bloomers. The Devil gave roses the choice, of being able to reproduce every month of the year with the chance that they would be killed by cold weather, or only being able to reproduce once a year with the ability to withstand the cold. Guess what they took? So when the advice from any source tells you that you must do something to help the rose go into dormancy, you know you are about to get some unsound advice.
Bad Advice: Cut few flowers from your bushes at this time of year and if you do cut them, only cut short stems. The reason for doing this is that any cutting done on the rose bush will cause it to produce new growth, and that new growth may be killed by the winter.
Good Advice: Enjoy your roses to the fullest extent possible. If you want to cut roses for the house, take as many as you want and cut stems as long as you like. Yes, it is likely that if warm sunny weather continues the rose will begin to produce new growth right below the cut where you removed the rose just like it always does. Whether this new growth lives or dies during the winter is completely irrelevant because it will be removed when you reduce the size of the bush during spring pruning since it will still be at the top of the bush.
Bad Advice: Do not prune away the dead flowers in the fall. Just remove the petals when they fade. This action allows the roses to produce rose hips (seeds) which is important if you want to help the roses go into dormancy.
Good Advice: Many gardeners take great pride in the way their gardens look, even in the fall. Many roses have grown quite tall during the summer season and will eventually need to be cut back to protect them from the winter winds. So, to keep your garden looking beautiful, continue to remove those spent blooms.
You may even want to cut longer stems than you did in the summer which will give you a little head start on cutting back the bushes, which you will probably do later in the season. On the other hand, if you do not want to prune away the dead flowers, removing the dead petals from the plants will keep your garden looking better. You will find that very few hips will develop because most modern roses tend to produce few hips.
Bad Advice: Roses need a rest period so that they will be rejuvenated for the next growing season, so remove the leaves which will signal the rose that it is time to become dormant.
Good Advice: Modern roses that are grown for the floral industry grow and bloom twelve months of the year, and often do this for many years and never get “a rest”. Your roses are the same. However, the cold weather that will come with our winters will cause most of the leaves to fall off our roses. Leaves that remain on the plant through the winter should be removed with spring pruning. Overwintered leaves are basically nonfunctional and are not very pretty, which is the one reason for removing them during spring pruning. There is no reason that leaves should be removed from the plants in the fall. Even while the cold causes leaf loss, the rose plant is not dormant. However, the roses overall growth is slowed to a crawl by the cold weather and short days of winter.
Semi Bad Advice: Make sure that you remove all of the leaves from the rose bed because they will reinfect your roses with disease in the spring.
Good Advice: Picking up the dead leaves from the rose garden may indeed make the garden look better but it will not reduce the incidence of disease in your garden next year and it is a lot of work. Most rose diseases overwinter on the rose canes (stems) either as active fungal lesions or as spores under the bud scales which are found up and down the rose canes. The reduction of disease in next year’s garden can be accomplished by intervening with fungicides as the rose begins to grow next spring. The spores that have been residing on the stems through the winter move to the new foliage and begin the disease cycle early in the year. Fungicides can stop that process while picking up leaves this fall will not. This is also why a cold winter will often be followed by a year of lighter than usual fungal activity. The canes are killed by the winter and are removed in spring pruning which removes much of the source of fungal infection as well.
Bad Advice: Do not apply any fertilizer with nitrogen in it because this will stimulate the rose to produce new growth. Instead apply a fertilizer with no nitrogen such as a 0-0-10 or 0-10-10, (the first is a potassium only fertilizer, the second is a potassium and phosphorous fertilizer), because these will help the plant into dormancy.
Good Advice: Apply no fertilizer for the rest of the year. The cooler weather and the shorter days are causing the growth of the rose to slow and the colder weather to come will reduce it to almost a standstill. Under these conditions the rose will not be taking any nutrients up from the soil. Any product that you add late in the fall will probably be leached through the root zone into our groundwater, which is not really what we want to do. If you were to apply nitrogen fertilizer at this time of year it would not stimulate new growth in the rose, instead longer days and warmer temperatures next spring will be the stimulus for the rose to produce new growth.