Why do my rose bushes have black spots?

Question

Why do my rose bushes have black spots?

Answer 1

Cause

Blackspot is a fungal disease most prevalent in wet weather as it is spread by water-splash or wind-blown rain. Susceptible cultivars can be severely defoliated if left untreated. The disease is most prevalent in clean air areas and occurs less frequently where atmospheric pollution is a problem.

This is what I use.

Fungicide for Mildew and Black Spot

1 tsp. baking soda

1 quart of water

8 to 10 drops of dish detergent

Dissolve baking soda in 1 quart of warm water.

add dish detergent and shake. until well mixed spray on roses early morning if possible.  Remove infected leaves from plant, then spray top and bottom of remaining leaf surfaces to control spread of the disease.

Spray once a week

Answer 2

Its a fungus called Black Spot and roses are very suseptible to it.  You will have to go to a garden center and buy a chemical to fight it.

As much as I love roses I don't grow them because I don't want to have to do all the chemicals to get nice flowers.

One thing to remember is rose bushes need to be deeply watered but don't get water on their leaves.  Mulch the ground under the bush.  There are two reasons for this.  It keeps the ground moist longer and keeps disease spores from splashing on the lower leaves of the bush.

Good Luck

Answer 3

A: they have black spot

I treat mine with Daconil

it works great

http://www.epinions.com/reviews/Ortho_Mu...

pick up all debris under the plant

remove all diseased leaves- the individual leaves aren't going to recover

remove all damaged stems

treat the plants..try to spray the undersides of the leaves and all the stems as well as the tops of the leaves.....kind of tricky

you will need to retreat in 10 days but the new growth will be healthy

during the winter when the temperature is between 40-80 degrees F spray the dormant plants with dormant oil spray

this will protect the dormant stems from re-infestation -

i swear by it

try not to let water splash up onto the plants when you water

pine needles or limestone gravel make good disease reducing  mulch.