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14 messages
26/04/2013 at 22:58

Does anybody out there have a definitive answer to black spot? I've tried all the usual sprays and solutions, and I clear dead leaves around the base of plants, and refresh the soil, but the dreaded spots eventually start appearing. The roses are of differing varieties and type, but they all seem susceptible. 

Any suggestions gratefully received!

26/04/2013 at 23:18

I don't have a definitive answer to black spot - if I did, any financial problems of mine would soon be over!t I was reading an older gardening book this week (from the 1970s) that recommended spraying with a jeyes fluid solution! I've also read this week that it is good for killing viine weevil bugs when watered onto pots. It isn't advertised for either of these tasks, possibly because it has not been tested adequately to receive EU approval.

I'm pretty familiar with the problem because I live in the west where the fungus grows fast because of the damp. The RHS recommend alternating spraying with different treatments to deal with the different strains of the fungus and to prevent resistance being built up.

27/04/2013 at 10:35

Thanks GG. I thought about watering the base of roses ( both planted and potted ),with Jeyes fluid - after your comments will give it a try.

Will let you have an update in 3 months! 

 

27/04/2013 at 12:49

Pentillie, Black spot is a fungus which affects the leaves and is transmitted by spores, so watering anything on the roots won't help.  All you can really do in addition to the things you have already mentioned is to more regularly spray the leaves and keep them really well fed.  On my clay soil, it doesn't matter what I do so just have to put up with it.  One rose "Peace" is about 40 years old and gets it really bad, but is still growing as strongly as ever.  If you see signs of black spot on the actual stems, cut them back really hard early next spring and it will lessen the effect for a couple of years.  Try and keep the roses as open in structure as possible - wine goblet shaped is recommended, as the more light and air that can get to the middle of the bushes, the better.

The JF might work if watered on roots of plants affected with vine weevils though.

27/04/2013 at 18:50

If using JF for spraying for vine weevil whar would be the proprtion of JF to water, please?

27/04/2013 at 22:15

here in Switzerland (and we are in a very damp and misty area), the rose centre recommends spraying with a copper-based fungicide very early in the spring.  It's harmful to insects, so only the one spray is recommended.  it's too late to do it now, so maybe for next year?  the rose expert told me to spray the rose and the ground around it liberally, and always to remove old leaves.  then a feeding of potash in spring, to build up the immune system.  after that, if the black spot is bad, proprietary fungicides.  they spray every two weeks, as their roses have to look good.  but i'd rather not.  i think i will root out the most susceptible roses and replace them more robust ones.

27/10/2013 at 10:51

Can I spray Rose plant itself with JF? and can I do it this time of year? I would love to get rid before the plant starts again in Spring.

27/10/2013 at 22:10

i also have problem with black spot so i think 'll prune low in the spring and spray the stems with jayes  as i've read that it can overwinter on the stems. I was also advised to spray with a rose tonic

28/10/2013 at 09:16

Some roses, such as Peace, are more susceptible to black spot than others. Keeping roses well fed and watered helps. In the RHS garden, Rosemoor, they only plant disease resistant roses.

28/10/2013 at 21:23

I too have a problem with black spot on a climbing rose - Pauls Scarlet.

Honeysuckle grows close by and that too gets black spots on it's leaves. Both planted about the same time the honeysuckle has romped away over an arch but the rose hasn't done what the packet says. It should grow to 200 to 300cm, it's going to be several years before that happens at the current rate of growth

29/10/2013 at 19:44

I have a Paul's Scarlet which nearly died from black spot and disease years ago. I then realised that the overhanging roof of the house was keeping it too dry. I sprayed it every 10 days with an anti-fungus and fed it and watered it copiously every few days. Now it it green and healthy and all the disease has gone.

30/10/2013 at 20:35

Will try spraying, is it better now to wait till Spring.

30/10/2013 at 22:42

Yes, too late now. Spray at first appearance of young leaves.

Lyn
31/10/2013 at 09:30

So, did you find the answer to your question, Matty?. This year I didnt use nematode and have found some vine weevil in my lily troughs, is it really as easy as watering in Jeyes fluid I wonder.

Off topic there!

Back to roses, I spray mine with the anti fungal spray very early in the season, before any leaves have black spot, then spray about once a fortnight whether they need it or not, just in case.

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14 messages