I am in Southern Ontario, Canada (Zone 5).

I transplanted a fairly large Black currant bush two years ago from my friend's garden. While I'm happy to see how resilient this plant is and that even in its first year it produced some fruit, I noticed that the issue we had last year (and I wrote it off to the stress of transplanting and very dry spring and summer) came back. This year we can hardly complain about lack of rain. It rains a lot. Yet, we are experiencing the same issue again.

Symptoms: first shriveling/curling of the leaves with some yellowing of the veins, then drying/dying of some tips of the older branches, drying berries that just started to form, then some spider webbing around those spots (not sure if related).

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I tried to prune away most of the problem branches last late Fall cutting down bush by ~30%. It looks a little better this year, but starting this drying out again this year.

I searched online, but I didn't find anything specific about currants that resembles what we are seeing. What could it be?


I tested pH of the soil in a few places in my garden this spring (one test was close to the bush) and it showed to be 6.5.

When I first planted it in October 2015, I didn't fertilize at first, but placed sheep manure compost around it before winter (few weeks later) as directed by "gardener friend". It was a very cold winter (with temperatures below -20 for a few weeks in the row) followed by brutally dry summer. I watered through the summer by hand and added more of the same compost around the bush. I applied 15 kg of sheep manure compost again early this spring. The bush is close to the lawn on one side and the vegetable garden on the other side.

  • @pnuts No, never heard of it. I will try it for sure... once it dries out. Thank you!
    – InitK
    Commented Jun 6, 2017 at 18:24
  • But the branches are good to produce berries for 2 or 3 years... Maybe we have different variety of currant.
    – InitK
    Commented Jun 6, 2017 at 18:33
  • Yes, I found that info too. I guess I'm just basing my opinions purely on my experience, and on the fact that I find it hard to prune so much. I will be more firm this year and remove all old wood. Hopefully my issue is in fact mites and rain will wash it away. If not - anything can be done about mites as a preventative measure next year? Does it mean that it will come back year after year and we are doomed?
    – InitK
    Commented Jun 6, 2017 at 18:42
  • 1
    I love blackcurrants too! it's the taste of summer from childhood to me. I updated the questions with some more details.
    – InitK
    Commented Jun 6, 2017 at 18:58
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    @stormy What would you recommend I should to do to fix the issue? Can you point me to anything "trustworthy" to read about the topic? I'm planning to bring more currants into my garden and want to treat them right :) Also, I feel that all the information you are sharing here should be placed into an answer to the question.
    – InitK
    Commented Jun 7, 2017 at 12:52

1 Answer 1


Decomposed organic matter should never be used as 'fertilizer'. When undecomposed the decomposers use up the nitrogen to do their job. What is left? All sources are different in chemical (nutrient) makeup. That is the thing; none of these manures are balanced. The decomposition itself uses most of the Nitrogen just to decompose. Decomposed organic matter is invaluable as a way to 'feed' the soil or rather the macro and micro soil organisms outside of the decomposers. The only way to improve soil is to add decomposed organic matter, to the top of the soil allowing the soil organisms who have to have only decomposed organic matter for food/energy to come up, eat, go back into the soil and poop it out mixing organic matter into the soil for you without any mechanization. I've been out on a sheep manure and gardening site explaining that sheep manure has to be decomposed as well. 'Hot' means not decomposed. Has more nitrogen than after decomposition and most certainly can affect your plants primarily because it is way out of balance. Too much Nitrogen in relation to the P and K will enhance fast growth, weak growth making a plant susceptible to disease. That manure will be broken down by decomposers who in the process use lots of nitrogen. Sucks any nitrogen out of your soil that it might have had as well as the nitrogen the manure began with. Until that stuff is fully decomposed all the other soil organisms go to sleep, dormancy or die. When there is decomposed organic matter available the soil organisms not responsible for decomposing finally wake up, reproduce, eating this stuff for energy. That is called a 'live' soil. Putting bark (not decomposed) or sheep manure (not decomposed) on your soil causes your soil organisms to go dormant until the decomposers have done their job, using up the Nitrogen to do their job.

Whether 'organic' or 'synthetic' the chemicals are identical. No matter their source, a Phosphorous atom is always a phosphorous atom. No differentiation between an 'organic' atom or a 'non organic' atom.

You have to give your plants balanced fertilizer. You have to take into account the 'standard' chemistry of decomposed sheep manure. Haven't been able to find that one yet. Look for an even number of NPK for a balanced fertilizer from a bag. Or if you want to get into this more, find a formulation higher N in proportion to P and K after the fruiting. Before that only fertilize with LOW N in proportion to P and K. That promotes reproductive growth.

If plants are not getting the chemistry they need with which to do photosynthesis, they will be weakened, vulnerable to disease. Which brings me back to the symptoms of your currant. I see a number of problems which I believe are the result of lack of chemicals (nutrients) your plant has to have to be healthy and resistant to diseases, insects.

Are you a smoker? Have you had any friends over that are smokers and have blown tobacco smoke on this plant or handled/touched this plant with tobacco on their fingers? Tobacco has a gnarly virus which is contraindicated for an awful lot of plants. This shrub looks like it has Mosaic Virus. One of the reasons is because there are leaves that look just fine and dandy. Newer leaves will be allotted chemistry if that chemistry is lacking first. Your plants show this yellowing on the newest leaves. I am thinking that these are the most vulnerable leaves to tobacco smoke and therefore are showing the symptoms of Mosaic Virus. mosaic virus on ribes. Check out the dead fruits.

Part of the reason is unbalanced fertilizer but the other would be tobacco smoke. If no smoker has touched or smoked around this plant, we need to continue this investigation! Grins. Let me know. Hold off on doing anything as yet, okay?

Well, if there are truly spider mite on this plant (fine fine webbing in the angles of branches and leaves) or get a cheapo specimen microscope ($10 - $14 on line, Amazon) and look at the leaf undersides. You should easily see them at 40X. My cheapo microscope goes up to 120X! Always important to see your insect before making battle plans. If there is a spider mite problem, Neem, is the best to use. Please never spray NEEM during the day, only at night. Some formulations say 'okay for bees' but I don't believe them. Spray only at night. Get the undersides of the leaves, too! Take a picture if possible of the webbing at least to send.

  • I also see leaf miner activity and powdery mildew...berry blight for sure. All because of imbalanced chemistry. I kid you not. Well, smokers if that is possible own equal responsibility. Mosaic virus really weakens a plant. Nothing to stop it other than pruning and proper fertilizer and new friends, grins!! Can help you through pruning as well; do you have bypass hand pruners? A pruning saw? Alcohol? Get them sharpened cause we'll have to walk through pruning (more ventilation less fungal disease such as powdery mildew and berry blight) and I love pruning!
    – stormy
    Commented Jun 7, 2017 at 18:51
  • First, we are not smokers and no smoker came close to this plant. We do have neighbors that smoke tobacco and other various weeds, but it's at least 80' away from my garden. Besides, it's the same problem that we had last year. Second, I believe that sheep manure compost was fully decomposed, I added it on the advice of some article about care for currants. Can I use something like "Tomato tone" by Espoma on currants? and when? I need to hunt for microscope too. I started to think that maybe it's time to start over and get new "clean" plants, but really want to understand how to do it right.
    – InitK
    Commented Jun 7, 2017 at 19:39
  • Yes, there was a lot more powdery mildew on the bush this morning. Since I pruned last year (removed all unsightly old wood), there are a lot of new branches glowing, so the plant became pretty crowded. I do have some hand pruners and spirits handy :) I'm thoroughly confused on what to do when with currants. I thought they are problem free plants, saw them growing without any care in grandma's garden. I don't think she ever touched them and we had loads of berries. Should I pull all that compost away from the bush? I have other places in the garden I could use it...
    – InitK
    Commented Jun 7, 2017 at 19:49

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