Sorry I can't help with your question, but I'm wondering what symptoms the rhubarb is showing?

This is what she wrote:

Last summer two of my rhubarb plants had several red leaves and the
plants failed to flourish, but they didn't die. Three other rhubarb
plants, which are planted next to the other two, did beautifully and
did not show any signs of having red leaves.

This spring those three plants have grown in leaps and bounds,
standing almost a foot and a half tall, while the other two are
struggling to make it out of the ground and are maybe a whopping 1 1/2
inches tall.

I tried to figure out what is wreaking havoc on my rhubarb and this is
the closest thing I've found that looks like the leaves did last year:
http://www.greengate.ca/aboutplants/plantdiseases/vegtablessmallfruit.html
( see the section regarding Red Leaf of rhubarb, with picture.)

I guess my question is, is there an
herbal concoction that might help these plants? Should I be concerned
about it spreading to the other three, currently, unaffected plants.
Or am I faced with the loss of those two rhubarb and should remove them.

(Side note: The plants were given to me last spring and planted fresh
in their current location, no prior sign of this red leaf thing.)

well, as the page says, either way they're toast, so I'd scrap them to simplify things .... rhubarb is easy to multiply by digging/splitting/replanting the roots .... but they need to be in a fairly moist, very rich soil, lack of which will also make them struggle along and even have patchy red on the leaves when mature and the ground gets quite dry

Bill

Agreed. Who knows why 2 out of 5 refuse to be healthy and vigorous, but no reason at all to keep the slackers around.

A lesson all gardeners learn sooner or later is that sometimes plants just do not do well even though their neighbors do fine.

One could try to figure out the issue, but removing the plants and replacing them with others is easier and most often more productive.

Start with a good, reliable soil test to see what the soil is and what is going on in the soil.

Start with a good, reliable soil test to see what the soil is and what is going on in the soil.

The 5 plants are all right next to each other. Would you suggest 5 soil tests (1 per plant) or just 2 (one for the healthy plants and one for the unhealthy ones)?

What should be tested for and where does one get this test?

Personally I would just replace the failing plants with divisions from the healthy plants. It's cheaper, faster and easier.

The most serious disease that would affect Rhubarb is root rot and that occurs only in too wet soils. Most all leaf diseases have very little affect on Rhubarb, so if there is a problem growing Rhubarb, even if the plants are very close, it is most likely a soil related problem and the only really good way to determine that is with a good, reliable soil test for nutrient load and soil pH.
If you plant healthy plants into an unhealthy soil you will get more unhealthy plants.

Heathen, tell your friend that Red Leaf disease of rhubarb cannot be 'fixed' or cured. There is no reasonable way of removing it from the soil. I would also think that if she attempted to transplant the remaining unaffected plants, that she would simply be planting the pathogens right along with those plants.

I think that a new location should be selected for some brand new plants.

I agree that the wise thing to do is to relocate. I also agree with dividing the healthy plants. The root cause could be because of a genetic difference, the unafflicted being the fittest.

rangier

I told her that originally when she said she thought it was a virus, I told her to remove it promptly so it won't spread... she didn't, but says it's still not thriving, so she's doing it now. It was the second year for rhubarb failures in that spot, so I suggested planting something else there forever. she was just hoping that there was a way to 'cure the soil'. I had the same sort of problem with salvia officinalis... 2 years in a row I planted it in what I thought was a perfect spot, great drainage etc. and it croaked... so I left it empty and now the thyme has spread and taken over that exact spot... whatever was in the soil affecting the sage, didn't affect the thyme!
My friend has said she plans on getting some soil testing done.
Thanks everyone!