what's wrong with my zinnias?

Desirai

11 years ago

Featured Answer

rhizo_1 (North AL) zone 7

11 years ago

Ignore ken.

You picture is a textbook image of a common disease of zinnia called Alternaria, which can cause leaf spot and flower blights.

Understanding this fungus disease is paramount to preventing another major outbreak next year. You'll need to address a variety of factors :

1. Housekeeping tasks include the removal of the plants and all of the debris from the area where they're planted. It will need to be disposed of, not put in the compost pile.

2. Some zinnia varieties are more disease resistant than others. That characteristic is usually well advertised in seed catalogs or in descriptions you can find on line.

3. Zinnias and other disease prone plants need to be grown with careful attention to disease prevention. Avoid overhead watering, over crowding, and frequent irrigation. Make sure that your zinnias are nutritionally taken care of....excess OR insufficient fertilization can contribute to disease onset.

4. Finally, alternaria can be controlled by pretty commonly available commercial fungicides, if you're interested in going that route. You would need to research the active ingredients to look for and become a label reader at the garden center.

I never use fungicides, and I grow zinnias. But I limit myself to those varieties that are tough as nails and those just aren't as appealing to most people. I'm in the south, which can make it extra challenging.

Since it is late in the season, I'm going to suggest that you begin with the garden housekeeping unless there are lots of flowers to enjoy until frost.

Over the winter, you can do your research and make your decisions about what direction to go in. I know that there are lots of people who grow zinnias successfully.....we can all help.

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Comments (12)

ken_adrian Adrian MI cold Z5
11 years ago
was your lawn recently sprayed for fall???

ken
Desirai
Original Author
11 years ago
No, we don't spray our yard for anything
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ken_adrian Adrian MI cold Z5
11 years ago
i realize you are in z7 ...

and i realize these plants can POSSIBLY last deep into fall ..

but some years.. you just chuck it in early ... and cut them all down... and that is the least invasive solution to your issue ...

the flowers themselves.. any flower.. are very ephemeral ... short lived ... and anything the lingers on them ... will cause them to fail/spot ... even just water sometimes ...

so i think it has to do with something that landed on the flower ... hence the spray ????

if it were me... i would cut off the affected flowers .... ignore the leaves... and enjoy them.. until they pissed me off so bad i cut them down for the year ... so... most likely.. they would be gone within 30 days or so ...

ken
Desirai
Original Author
11 years ago
Rhizo, question

My zinnias are in the same bed as my dahlias, and my dahlias have been ugly as hell, deformed, and sad looking all year.

Could these 2 things be related? I poste din the dahlia forum a few weeks back, and many people suggested that something was wrong with my soil.
rhizo_1 (North AL) zone 7
11 years ago
Something going on in that area could be contributing to fungus problems with your plants. Dahlias are susceptible to even more diseases than zinnia!

Overly moist conditions, frequent overhead irrigation, and poorly drained soils can all contribute to disease outbreaks in plants.

Most outdoor soils contain all manner of pathogenic propaguled. But only if a susceptible plant is present AND the right conditions will the disease show up.

You need to evaluate the environment within this planting bed.
Desirai
Original Author
11 years ago
this bed is not very big at all, maybe 2ft by 2ft. should i just dig up all of the soil? can you recommend what i should do. i filled it with bacto brand potting soil last year. i dont know much about diseases and fungicide and herbicide and all that.
dbarron
11 years ago
That could be part of your issue. Pottings soils aren't made to be 'earth' bed type soils.
rhizo_1 (North AL) zone 7
11 years ago
Baccto used to be one of the very worst of packaged potting mixes. It used to be made of mucky sedge peat......OOPS, I see that it still is!

Awful stuff. That has absolutely contributed to the problem!

Any reason why you can't plant directly into the existing, native soil?
Desirai
Original Author
11 years ago
i built a raised bed with bricks and stone and then bought 3 50lb bags of it because it was only $5/ea lol easier than digging up yard dirt or buying $25/ea bags of dirt
dbarron
11 years ago
And you got the results we would expect.
Desirai
Original Author
11 years ago
ok so if bacto is the most probable culprit what should i do? should i till up the entire bed and if so what brand of soil should i use?? a lot of my yard is clay or rock is that ok for dahlias??