Sunday, August 14, 2016

Rust isn't only on cars

The last time I grew hollyhocks was four summers ago. If you type hollyhocks into the search bar, you may see them. When we decided on the new garden this year, I wanted to plant them again. We started the seeds inside and they were a good size when we put them outdoors. For a while the plants were a lush green and very healthy. They got tall and the buds looked great in this picture from July 30.


but the leaves had these odd little spots.


You might think, oh, those aren't so bad, but these were the leaves which were just beginning to be infected. Here are the leaves which were in worse condition.




And now, a couple weeks later


Even the buds are affected


But amidst all this ugliness, the hollyhock flowers continue to open and bloom and look as beautiful as any prizewinner, as long as you focus on just them!



When the problem first appeared I searched online and found a very informative site.

Puccinia malvacearum, the rust fungus that infects hollyhock, causes yellow spots on the upper leaf surface, and orange-brown raised pustules on the lower leaf surface.   Wet conditions promote infection by the rust fungus. The lower leaves typically show symptoms first, and the disease slowly progresses to upper leaves over the summer. Infected leaves eventually turn brown, wilt, and die. Wind and splashing rain help spread the spores of the fungus, so spacing plants to promote good air circulation can help slow the progression of the disease. Because wet conditions favor infection, water the soil around the plants rather than wetting the leaves with overhead irrigation if possible.

I grew them in the corner of the fence, and they were too crowded. Four years ago, they were out in the other garden with plenty of airflow. I did have a big problem with Japanese beetles but no rust. This year there have been very few of them around anywhere. Funny how bugs go in cycles.

So I plan to clean up very well, and next year I won't grow them in the same place again. I'll give them lots of space and will water from below. 

And I wanted to note that the mallow was also affected by rust. Hollyhock and mallow belong to the same family malvaceae

When I mentioned in the post about the new garden that I had a whole blog entry planned on hollyhocks, both Lisa and Stephanie commented that they have a terrible time with rust, so here's hoping these tips will help all of us! Stay tuned to see if next summer's hollyhocks are rust free.

22 comments:

  1. I have only one hollyhock this year. A volunteer that popped up in a difficult place. It won't bloom until next year but I doubt it will be rust free no matter what. But I will let you know how it goes. Thanks for the info.

    ReplyDelete
  2. Fingers crossed for a better hollyhock summer next year for all of us. It's hard to give up on flowers this pretty. They add so much to a cottage garden appearance which I love. Thank you for sharing the good information.

    ReplyDelete
    Replies
    1. You're welcome! I hope it works for all of us.

      Delete
  3. My morning glory plants have a fungal disease this summer - they bloom away, but the leaves are yellow with black spots - ugly looking. I think perhaps they also aren't getting enough air circulation. Looked lush and beautiful even last month. I do love them so.
    Mary

    ReplyDelete
    Replies
    1. Have you looked it up or checked with an extension service to find out what the cause is? Have you had a lot of rain? I've never grown morning glories. They are so beautiful.

      Delete
    2. My morning glories are doing the same thing, littlemancat. They have gorgeous, prolific blooms, but yellow leaves and black spots. We have had a lot of rain here more seeds came up here than in past years. They self-seed in a pot.
      Nan, I don't grow hollyhocks, but, a few of my friends do and they are having the same problems. These things can be very frustrating, I know, but, your blooms are gorgeous.

      Delete
    3. Penny, have you looked up the problem? I wonder if the 'lot of rain' has anything to do with it. Have you had this problem in drier summers? I wonder if your friends might be interested in the link? But maybe it is the rain.

      Delete
  4. So sorry to see your hollyhocks suffering. I must admit I always thought they are the same as mallows - to me, they were all malve flowers. It is good that I keep reading your blog - it gives me the opportunity to learn more about gardening and plants! (among many other things)

    ReplyDelete
    Replies
    1. I learn from people's blogs all the time!

      Delete
  5. hat a shame, Nan. I remember seeing these on my Gram's hollyhocks which had self-seeded over years and were crowded.

    ReplyDelete
    Replies
    1. I've never had self-seeded ones. Too cold maybe. I treat them as annuals. The mallow however self-seeds all over!

      Delete
  6. Well, they are beautiful, nonetheless. Such a pink!

    I didn't realize that hollyhocks were mallows. We have a couple of wild mallows here and you can see the family resemblance. (Maybe I should do a post on them!)

    ReplyDelete
    Replies
    1. I think that lavatera is also in the same family. I love them all. And you should do a post!!

      Delete
  7. Who knew that rust was a fungus? It seems brave that the flowers just keep blooming so beautifully in spite of everything.

    ReplyDelete
    Replies
    1. The same thing happened the year they were attacked by Japanese beetles. The leaves were decimated, and yet the flowers were perfect! Brave, indeed.

      Delete
  8. I tried to post photos of my hollyhocks so you all could see the differences ... mine are growing at 7,200 feet elevation in a semi-arid (desert) landscape in Santa Fe, New Mexico, in the US. I notice I too have some rust, but mine seems to be only on the lower leaves. These grow to be 6+ feet and, so far, are self germinating. Alas, my photos would not paste to this blog.

    ReplyDelete
    Replies
    1. Thanks for trying, and thanks for telling me. Mine are six feet, too, and the flowers seem not to be a bit bothered by the rust.

      Delete
  9. I'm going to plant hollyhocks next year. They're so pretty! I'll put your tips in my garden folder, otherwise I'll certainly forget.Thanks Nan!

    ReplyDelete
    Replies
    1. They are such lovely flowers. You will certainly enjoy them.

      Delete
  10. I love hollyhocks! And rust is a real issue with some varieties. The ones that I grew in my Reading, VT garden so many years ago never had a rust issue. They were a dark maroonish red. I've also had good luck with some coral/pink ones. The hollyhock that I have purchased at garden shops have all succumbed to rust. The seeds that have come from friends healthy plants have done well.

    ReplyDelete
    Replies
    1. We started our hollyhocks from seed. I'm hoping the problem this year was simple overcrowding. It didn't happen the other year we grew them - in a more open space. Fingers crossed.

      Delete

I am really going to try and respond to your comments as soon as they come in! Please do come back if you've asked a question.
Also, you may comment on any post, no matter how old, and I will see it.