Roses and Black Spot

[wayne crimi]

I am having a chronic problem with my Rosebushes.

I bought an extremely healthy looking one last year and noticed a problem with the leaves after a few weeks. I was new to gardening so I didn't act right away. When it got worse I did some research and concluded it was black spot. I bought a spray and followed the instructions for the remainder of the summer.

It survived the winter, but did not come back this year nearly as healthy and full as when I bought it. Several weeks into the spring I noticed the problem again. I acted on the very first day (I was monitoring the situation daily). Despite repeated spraying and removal of the lower level problem leaves, it continued to spread upward. Right now I am looking at what is essentially a leafless rosebush. It is clearly still alive because the branches remain green, but things don't look good.

I bought a second one this year and the same problem occurred with it after about a month DESPITE preventative spraying. I suspect I am looking at a repeat performance with this and I am not optimistic about the survival of the other.

Any insights at all as top what may be causing the problem and what I can do about it would be appreciated. Thanks

[Andre]

I am trying this organic recipe from Rose Magazine this weekend for my blackspot:

[Jim Carlock]

Somewhere, I have recently read that planting chives next to roses will control the black spot. I don't know how true this is, but unless someone else indicates negatively, it might be worth a try.

[Sunflower]

Some roses are more succeptible to disease than others. Some climates provide more disease pressure than others. Some winters are more challenging for roses than others. Some fungicides are more effective than others. No fungicide will eradicate black spot once it has a foothold on your rose. Fungicides are preventatives only. The best method to control black spot is to purchase varieties that are not prone to it and get rid of ones that are. Roses that look healthy at a nursery have been sprayed to prevent disease, and I wouldn't trust 99% of most nurseries to know which varieties would work well in a no spray situation. The best source of varietal recommendation would be a local rose society, but even then a list will be biased towards those who spray regularly and describe a bush as "disease resistant" WITH spraying. That's BS as far as I'm concerned. "Disease resistant" to me means it will retain at least 60% of it's foliage when left unsprayed, or has an extremely rapid recovery rate if it loses all of it's foliage. But, I'm in MS, the hot and humid capital of the South, and growing roses here is very challenging because of the constant fungal pressures. In a shorter growing season or some place with less heat and humidity, disease resistant varieties might be ones that keep their foliage till frost.

Which varieties are you growing? Where are you located? Which fungicides have you used and when have you used them? How much spring pruning did you do, or were forced to do by Mother Nature?

[Sunflower]

powdery mildew. It won't touch black spot. In fact, the whole thing is something of a joke.

[Sunflower]

deter spider mites. It does nothing to prevent fungal infections. Black spot is mostly carried over and reproduces from lesions on the canes, so no method that doesn't involve coating the canes and leaves with some substance will stand a chance of working as a preventative.

[Jim Carlock]

The person that posted seems to be in NY. I'll let him or her indicate that though. I only looked at the header to the message that he or she posted.

I'll leave the expert advice up to others. I am good at research and learning from the research. The following website indicates that chives have long been planted next to roses. They only seem to hint that it helps deter certain pests and attract other certain pests. Some links that suggest companion planting for roses include:

for:

chives "black spot" roses

on google turns up 382 links. And those are from the first ten links presented. :-)

I have some roses out front that had black spot on them. I'll have to wait until next year to see if the chives help, as I just put in the seed. I tried to grow chives earlier this year but for some reason none of the seeds germinated. Maybe the soil is too rich ?

[Phisherman]

[Paul E. Lehmann]

I have roses at the head of each row in my vineyard. I spray them the same time I spray the vines. I normally use both sulphur and Penncozeb at the rate of: Sulphur - at rate of 3.84 oz per 4 gallon packpack spray tank Penncozeb - at rate of 2.56 oz per 4 gallon backpack spran tank

If you don't have a lot of roses, you could just just adjust for half a backpack tank etc.

You can also use Ziram in place of the Penncozeb or Tenncop (a Copper fungicide) in place of the Sulphur.

If you already have a black spot problem, you might consider using a systemic such as Nova at the rate of about 5 grams per back pack spray tank.

The Sulphur and Copper will do nothing for the black spot but they are good for powderly mildew which Penncozeb or Ziram are not too good at controlling.