"honey-do" wrote in message
...
I recently read an article in an organic magazine that suggested using
Baking Soda and horticulture oil as a remedy for black spots on roses.

Has anyone tried this, or do you know of a remedy that might work? I
have tried many fungicides including dormant sprays and still have a
HUGE problem.

Thanks in advance!


The Cornell method of fugus control works great for powdery mildew. It
doesn't touch black spot, so don't waste your time, money, and effort. If
you are going to go to the trouble of spraying, pick something that works.
You need to go to a local nursery and find some manzate or mancozeb (same
active ingredients). Use it mixed as directed (add a bit of vinegar to the
water if your water is alkaline) at 3 day intervals for 4 sprayings. Only
mix what you can apply at once, as it rapidly loses effectiveness,
especially in alkaline water (a matter of a few hours). 7 days from the 4th
mancozeb spraying, you need to spray with a fungicide with an alternative
method of action. Funginex, Immunox, BannerMaxx (or Fertilome Systemic
Fungicide, which is the generic version of BannerMaxx, i.e. propiconazole)
One of these ought to be easily available. The advantage to the
propiconazole is that it has a 14-21 day spray interval, thus reducing the
time you are out in the garden spraying. Funginex and Immunox have a 7 day
spray interval. Whichever you choose, continue to spray at the suggested
interval, and every other spraying, combine it with the manzate. Your roses
will be at least 95% clean for the rest of the summer and fall. Spraying
fungicides is a preventative though, and you will not see it cure any of the
affected foliage. The new foliage that grows in clean will remain clean if
kept sprayed. Next spring, begin spraying as soon as you have leaf out and
your roses will remain healthy. To promote new growth now, go to a feed
store and find some alfalfa for horses. Alfalfa contains a growth hormone
which will promote a lot of new growth above and beyond the NPK it contains.
Do not apply epsom salts unless you have had a professional soil test that
shows your soil is low in magnesium, as many soils already contain an almost
toxic level already and adding more can result in you killing your plants.

Or, if you prefer to not spray, get rid of the more disease prone ones like
Don Juan and grow something else like Dortmund. There are lots of roses out
there that don't require spraying, but your local nursery won't know about
them or stock them. Listen to gardeners in your area who grow roses and
don't spray and pick a few they recommend. Most modern roses like hybrid
teas, floribundas, and modern large flowered climbers will *not* be on the
list of anyone who is seriously no spray, so if you get a list of
"reccommended varieties" from a rose society that contains any of them, then
the whole list is probably suspect and formed by gardeners who think disease
resistance means that it doesn't spot *with* a regular spray program.. In
the north, portlands, polyanthas, hybrid musks, and rugosas are good
choices. In the south, teas, chinas, polyanthas, hybrid musks, and
noisettes are good choices. Most of these will only be available mail order
through specialty nurseries like Kedem's, Chamblee's or Ashdown's, but it's
worth the trouble if you really are committed to a no spray lifestyle.

Sunflower
MS 7b