What can I do for my Rose?

Question

It started out fine this spring. Then the leaves started turning yellow with black spots, so the local nursery told me to spray a fungiside on it. The leaves are still doing that, plus there are hardly any left. There are three new shoots coming from the top, but the stems are to small to support the blooms. Should I cut it back, and let it start from closer to the base?

Answer 1

Diplocarpon rosae is your culprit. The fungus survives the winter in fallen leaves and in crevasses in the stem. Raking and removing these leaves each fall may provide some control. Avoid watering the plants by splashing water on or about the fallen leaves then back onto the plant.
Cutting the stems will make the plant work that much harder to come back. Leave the stems but include them when you spray.
At this point your BS needs a rotation of fungicides. This prevents the fungus from building up a resistance to the fungicide. Do not use an insecticide if you do not need one. You will only be breeding more pesticide resistant insects and killing any beneficial insects unnecessarily.
Below I have listed the classes of fungicides and how they act.
To save your roses you need to use Aliette first. It is the only fully systemic fungicide on the market. Try to find what class you have bought and select something from the third class. Organic methods are only in the contact class and should be used as much as possible because many of the chemicals are harmful to soil invertebrates. If they are not healthy your soil will not support your plants well. But first get the BS under control then ask how to get the soil cycles reestablished. Some fungicides say to spray in 7 or 10 or 14 days. Right now do it weekly for four weeks then drop down to recommended levels.

There are I - Contact Fungicides, 2- Penetrant & Locally Systemic Fungicides, and 3 - plant wide 1 Systemic Fungicide.
I- Contact is a “broad spectrum multi-site surface protectant” They remain on the leaf surface, acting as an exterior shield to fungi. This is the most common method of controlling BS, before it becomes a problem.
Potassium bicarbonate; Amicarb 100 Keep off soil
Copper fungicide; May cause soil damage with long term use.
Fish emulsion/seaweed (kelp) — Many rosarians achieved the best results by applying these mixtures on a regular basis. Will help build good soil also.
Milk 1:7 water Dried milk works as well as fresh. Use weekly in spray rotation.
Whole neem oil this is also an insectide, miticide.
Dithane; Dithane-Ultra, Mancozeb, Mancozin, Manzate 200
Baking soda/horticultural oil — Tests performed by Cornell and Auburn universities in the U.S. confirm this as my favorite powdery mildew black spot control. Mixed at a rate of 1 rounded tablespoon baking soda (sodium bicarbonate) and 1 tablespoon horticultural oil per gallon of water, this material is sprayed on foliage and stems weekly when the disease first appears. Use caution to keep the spray confined to the plant, thus reducing the potential for sodium bicarbonate buildup in the soil.
Bordeaux Mixture; A mixture of copper and lime, Bordeaux Mix should be combined with Saf-T-Side to make a very effective dormant spray. For northern gardeners, this spray is best used in fall, to prevent spores and insects from overwintering, to speed dormancy in preparation for cold weather, and to defoliate late fall plants. Rate: 1/2 cup per gallon along with 4 tablespoons per gallon of Saf-T-Side.

2- Penetrant -Locally Systemic Fungicides. These are absorbed but not translocated far from the site of uptake. They serve to prevent the development of disease at (and in a small zone surrounding) the site of uptake.
Chloroneb; Terremec SP
iprodione ; Chipco 26GT
vinclozolin ; Curalan, Touche, Vorlan

Systemic “single-site locally systemic” enters the plants xylem stream so is carried out to the leaves.
Benomyl ; Benex, Benlate(but is toxic to earthworms)
Thiophanate-methyl; Cleary’s 3336
There are others that also enter the phloem so go to the roots.
Propiconazole; Banner Maxx
Fenarimol; Rubigan
Myclobutanil; Eagle, Immunox

Aliette is the only truly systemic fungicide, moving to root and crown, and it works on downy mildew.

Example
Week I Systemic only Aliette
Week 2 Single Site Local (like Banner Maxx)
Week 3 Broad Spectrum (Fish and seaweed or milk)
Week 4 Single Site Local
Week 6 Systemic only Aliette
Week 7 Broad Spectrum Baking soda/horticultural oil
Week 8 Single Site Local
Keep on spraying the fish emulsion and seaweed whenever using a hose end sprayer on all you plants.
The baking soda mix is good for mildew on phlox or dahlias and on plants the aphid's honeydew is mildewing.

Answer 2

Spraying with a fungicide is exactly right, but did they not tell you that all the now affected leaves will not recover? Those leaves are going to fall off and the fungicide is supposed to keep the new leaves and those leaves not affected from getting the fungus. Bayer Advance has a product out called Alll-in-One and is an inseciticide, fungicide and fertilizer all in one easy to use mix. You mix with water and pour at the base of the rose and it soaks up the much needed chemicals. It says to do this every 6 weeks, but I have had better success using it every 4 weeks. Since your rose is so bad already, I would go ahead and cut back the worst part, treat it with the Bayer All-in One and continue to spray the fungicide as the previous person explained. Never water the entire plant, only at the base and make sure it is getting at least 6 hours of sun. Good Luck!

Answer 3

You should be spraying once a week as soon as the leaves start shooting out and after every rain. Also spray the ground under the growth. When I was laid up and couldn't work with mine and they got pretty bad so I cut them off at the ground and started over. Don't wait and do it too late into the growing season. When you water them don't get the leaves wet. Never water them in the evening. When you trim, take some of the branches in the center out completely so the breeze can help keep the leaves dry. Try to plant them in open areas where they are going to benefit from any breeze. Sheltered areas will be the most difficult to prevent any fungus from attacking the leaves. Hope this helps.

Answer 4

Ortho makes a good food and fungicide called RosePride You must not water them overhead; instead water them close the roots and always early in the morning so that the sun can dry the plants all day. Never water at night, either.

Cut off all the yellowed and spotted leaves, and burn them; or at least throw them into the garbage. Do not compost them.

Water and apply your RosePride, and spray with the can that comes with it. You need to do this about every six weeks with this product.

Answer 5

I have 8 rose bushes and i fight constantly with the fungus and mold I live in south Texas. I have used immunox. Its a spray for plants and it works rather well. but its hard to get rid of once you get it (the fungus i mean). good luck

Answer 6

A much cooler name than William Bailey.