Do You Have Black Spots on Your Rose Leaves- Just the Facts

Black Spot of Rose

The rose (Chinese: 玫瑰)has been one of the most elegant and sought after shrubs to have in the garden since the early twentieth century. With a flower that is unmatched in its beauty, and a fragrance that rekindles happy memories from the past, the rose has earned its place among the very best in the garden, and it is the best gifts for Mother’s Day (Chinese: 母親節).

With all it’s positives though, one thing still holds true for the flower of love, it ican be very difficult to manage properly thru an entire season.

The fact is, roses are very finicky and will require 4 things throughout the season to remain healthy and flower profusely; they are sunlight, water, fertilizer and constant airflow. All are required in high doses and more importantly, each must be managed precisely to avoid problems that include insects and disease.

Aphids and Japanese Beetles are the two major insects that you will tangle with when you grow roses and luckily, they are fairly easy to manage. These insects are active only at certain times of the season, Aphids mostly in the spring and Japanese Beetles in the early summer, and knowing when to manage helps you prepare for the process.

Your biggest headache will come from a leaf disease known as Black spot. It is a fungal disease that attacks the leaf of the rose shrub when the weather is warm, humid and rainy. Sadly, this pretty much encompasses the entire spring, summer and early fall season and will require you to stay on your toes.

The fungi requires moisture and humidity to proliferate and under ideal conditions, symptoms can appear in 4 to 5 days, first as black spots that fade to yellow and eventually, growing together to kill the leaf. When conditions are severe, plants can totally defoliate, leaving only the bare canes.

There are various cultural methods that you need to follow to help alleviate some of the pressure during the season. Before you resort to chemicals try the methods below first.

When watering, try to keep the foliage as dry as possible. Avoid all overhead irrigation and wetting of the leaves especially late in the day.

Water deeply every 4 days if no rain is forecast and add a slow release fertilizer every 6- 8 weeks to keep the plants healthy.

Only plant roses in locations where they will get at least 10 hours of sunlight and there is plenty of air movement. Lack of continued air movement encourages leaves to remain moist and exacerbates disease conditions.

Prune roses on a bi-weekly basis focusing on the crossing branches of the interior. This will keep the shrub maintained and increase air movement thru the leaves.

Keep the planting beds clean of all leaf debris during the season. Removal of damaged leaves and diseased canes will help keep further spread under control.

Fungicide applications, if needed must be made at intervals of 7 to 10 days in wet weather. This will not remove the black spots on any existing leaves; it will only help prevent the newly emerging leaves from future infections. Make sure you cover all leaf surfaces to the point of run off when spraying.

The older varieties of the rose like the Hybrid Tea are very susceptible with the Shrub and Rugosa showing some resistance. The newer variety of Knockout Rose is very resistant and a good choice moving forward. Good luck and good growing. If you want to just buy rose directly, or other gifts for mother’s days (Chinese: 母親節禮物), you can go tovSecret Florists to take a look.