Garden Dilemmas, Delights & Discoveries, Ask Mary Stone, New Jersey Garden blog

Deformed Flowers on Black Eyed Susan

a brigth yellow black-eyed susan flower with half-sized petals

Hello Fellow Readers, I have an assortment of deformed and dwarfed flowers on my Black-eyed Susan (Rudbeckia) and Coneflower (Echinacea). In addition to distorted petals, some flowers didn’t form at all.  Plus, the ends of others look like something nibbled them off.

This year, the foliage looks terrific, unlike the last two when riddled with powdery mildew from being overly wet. This summer is on the dry side with plenty of heat, and the happy plants held the promise of a plethora of blooms—instead, it’s a confusing dilemma. On went the research cap.

a purple flower with dwarfed petals with a bumble bee

Dwarfed leaves on Echinacea

Is the dilemma Tarnished Plant Bugs or Lace Bugs? 

I learned about tarnished plant bugs (Lygus lineolaris) that can disfigure leaves and flower buds on rudbeckias and echinacea, causing them not to bloom. Or the flowers have petals only on one side.

There’s Lace Bugs, a large family of insects that also sucks the sap out of leaves, disfiguring them. I’ve seen a few of the small (1/8th to 3/8th an inch long) lacey-winged things flying around. But it’s the tiny black spots under the leaves called frass (a polite way of saying bug poop) that points to them maybe being the culprit.

Or thrips? 

Or is it tiny thrips (1/25th an inch long) attracted to yellow, white, and light-colored flowers sucking the daylights out of them?  In major infestations, the plants themselves become deformed and splotchy. Hmmm, not the case with mine. But if so, like with the beforementioned bugs, insecticidal soap, or my tried-and-true Neem Oil will do the trick. Plus, cleaning up the garden in the fall limits their overwintering there, though contrary to my desire to keep the dry seed heads standing for our feathered friends.

Sadly, it’s Aster Yellows for which there is no cure.

After sifting through all these maladies, I’ve narrowed the dilemma down to Aster Yellows, which affects over 300 species of plants, including vegetables like potatoes and carrots. It is caused by a pathogen called phytoplasma transmitted primarily by leafhoppers. By the time symptoms appear, initially often yellowing foliage before the deformed or dwarfed flowerheads, it’s too late. There is no cure. Removing the infected plants, including the roots, is the only way to end the cycle of spreading the disease to other plants. Toss all the plant parts into a plastic bag and in the regular trash—a sad end to beautiful plants.

Mary Stone, Garden Dilemmas, Ask Mary Stone,Gardening tips, Garden Blogs, Stone Associates Landscape Design, Garden Blog, Mary Stone with Miss Ellie Mae

Miss Ellie Mae & I at “The Top of the World

A personal note about our dear Miss Ellie

Before I sign off, if I may share news about Miss Ellie, we learned that she has cancer for which there is no treatment. As you know, Miss Ellie is the mascot for our column since we began our weekly chats. She arrived unexpectedly eleven years ago during a tough time of transition. I’m doubly blessed as Curt came into my life about the same time. Together we shared a journey of recovery. Ellie, from the neglect and isolation of living alone in a cage, rarely fed or watered, with no protection from the hot Georgian sun. I from the years of neglect and loneliness of addiction.

Ellie was about a year old when she arrived, making her about twelve now— a long life for golden, but it never seems long enough. We will cherish all the days we still have. Thank you, kind readers, for your loving thoughts and prayers. Garden Dilemmas? (and now on your favorite Podcast App.)


Though it’s sad to lose beautiful plants riddled with disease, there is the hope of renewal and memories that will last forever.

a hot pink echincacea flower with an orance center with a bee.

A Healthy Echinacea

yellow black eyed susan flowers next to light blue hydrangea flower

And, my happy rudbeckia peaking through the hydrangea.

Tune in to the Garden Dilemmas Podcast featuring this story.

Click through to learn more about Aster Yellows.

Column updated 8/22/21

Mary Stone, owner of Stone Associates Landscape Design & Consulting. As a Landscape Designer, I am grateful for the joy of helping others beautify their surroundings which often leads to sharing encouragement and life experiences. These relationships inspired my weekly column published in THE PRESS, 'Garden Dilemmas? Ask Mary', began in 2012. I dream of growing the evolving community of readers into an interactive forum to share encouragement and support in Garden and Personal Recoveries - seeking nature’s inspirations, stimulating growth, weeding undesirables, embracing the unexpected. Thank you for visiting! Mary
  1. Dorrie Reply

    Mary, a couple stocks on one of my Black eyed Susan plants are wide and the blossoms weird – elongated centers. I was showing my sister and when she got home in Vt found a few on her Coneflowers. Do you have any idea the problem? I have photos but wasn’t sure how to share them.

    • Mary Stone Reply

      Hi Dorrie, I can’t say as I’ve seen elongated centers on Black-eyed Susans. Yes, please send photos to and hopefully can get to the bottom of your garden dilemma. Thanks for your message and for reading my column, Mary

  2. Andrea Wells Reply

    Hi Mary,
    A few of my black eyed susans have petals coming out of their brown centers. Someone said they thought it was aster yellows. Some of the flowers have brown petals, don’t think any are dwarfed. I do have an echinacea I recently bought, still in its pot, that has flowers with really small petals… But it got really dry and almost died while I was away so I thought that might be the cause. What do you think? Do we have aster yellows? Wondering how we can know for sure. Thank you!!

    • Mary Stone Reply

      Hello Andrea, Well, that is a mystery. It sounds like it could be Aster Yellows, but I would check with your local Extension Office to be sure. Thanks for reading my column, Mary

Leave a Reply


This site uses Akismet to reduce spam. Learn how your comment data is processed.