|
|
The Rolla Daily News - Rolla, MO
  • Nature's Advocate: A few challenges of growing roses

  • Although many consumers have embraced the relatively carefree, disease resistant and ever blooming shrub rose series Knockout since its first introduction in 2000, the hybrid tea rose is still a very popular rose throughout the United States.
    • email print
  • Although many consumers have embraced the relatively carefree, disease resistant and ever blooming shrub rose series Knockout since its first introduction in 2000, the hybrid tea rose is still a very popular rose throughout the United States.
    It is the ultimate "image" of florist rose bouquets, noted not only for its beauty but often scent. Hybrid tea roses have been the backbone to rose gardens throughout the country since they were first introduced to the market in 1867.
    Dr. David Trinklein, University of Missouri Extension state specialist suggests planting the hybrid tea rose cultivar 'Mr. Lincoln,' one that he has found to do well in the Missouri climate.
    Other cultivars recommended by the Missouri Botanical Garden include the orange hybrid tea rose 'Tiffany' and the pink floribunda rose 'Fashion' to name a few.
    In the Missouri climate, growing hybrid tea, grandiflora and floribunda groups of roses can be a little difficult. They can be prone to disease and insect pressure and are less cold hardy than shrub roses such as Knockout.
    But this doesn't make them impossible to grow. If you are up for the challenge, there are a few maintenance tips one should address this fall to help ensure a healthy return on these rose canes in the spring.
    Two challenges
    Roses prefer growing in loose, well drained, moist soil (like a rung out sponge) in full sun (no less than six hours per day).
    One of the greatest disease pressures of non-resistant rose cultivars is the fungal disease black spot (Diplocarpon rosae).
    Most rose gardeners have battled this defoliating disease on a regular basis in Missouri. It thrives in moist, warm (59-81 degrees F) environments, and chlorotic leaves and black lesion symptoms commonly show up on roses during wet spring weather but can happen anytime the conditions are conducive for the pathogen's spread.
    One of the best management practices of controlling black spot of roses is an integrated pest management approach.
    In the fall, it is best to make sure that all diseased canes and leaf debris are cleaned up from the site to slashing rain and overhead irrigation from spreading the fungi from the diseased leaf debris below the plants onto healthy foliage above.
    Because water on the leaf surface of roses helps spreads the disease, the faster the foliage dries after a rainstorm or morning dew, the better. Planting roses in a spot with good airflow is important to disease management.
    Along with debris management, good airflow, mulching the soil to prevent water splashing and limiting overhead irrigation, in the spring a preventative fungicide labeled for black spot control can be used as part of an integrated pest management plan.
    There are roses available that have resistance to black spot. For information on rose cultivars with black spot resistance, Ohio State University Extension has a great fact sheet available online at: http://ohioline.osu.edu/hyg-fact/3000/pdf/3072.pdf
    Page 2 of 2 - Another common problem which often occurs with cold sensitive hybrid tea roses and other winter sensitive rose groups is winter damage of the above ground canes.
    The Missouri Botanical Garden recommends after cold temperatures set in and temperatures at times are dropping below 20 degrees F to begin the process of adding winter protection around the base of the roses.
    Loose, well drained soil, decomposed compost, hardwood mulch or sawdust can be used in the process to construct a mound piled up 10-12 inches tall around the canes. With an optional additional thin layer of straw, this mounding of rose canes will protect them from dehydration and drastic freezing and thawing temperatures which often occur in Missouri winters.
    Once temperatures begin to warm in the spring and the threat of a hard freeze is less, this mound should be removed to the original soil level, and a 2-inch layer of mulch added in its place.
    For more information regarding care of roses, see the Extension guide #G6601 found at: http://extension.missouri.edu/p/G6601
        • »  EVENTS CALENDAR