Knowledgebase

Sunflower problem #807758

Asked August 23, 2022, 7:51 PM EDT

Some of my sunflowers have been falling over. When I cut them down, I notice that inside of the stem is brown and mushy. There is insect damage to the leaves too. Please advise! Thanks! Andrea

Anne Arundel County Maryland

Expert Response

Hi Andrea!

Sunflowers can get several stem boring pests including Dectes Stem Borer, Sunflower Stem Weevil, and Sunflower Maggot. Try cutting into other parts of the stem and see if you can locate the pest. Compare to photos and identification cues on pages 48-53 of the ID Guide for Sunflower Insect Pests from South Dakota State University Extension. It is geared towards commercial growers, so the recommendations for management are not suitable for residential gardeners. These pests have natural predators and spraying anything would harm pollinators visiting the plants. 

You can leave the broken stems upright in the garden - I do this with my sunflower stalks and in the spring sometimes I will find that an insect or pollinator has made its home inside! You can also bundle the already cut stems and leave them to dry for cavity-nesting bees. 

Jamie

Answered by the Home and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied August 24, 2022, 10:23 AM EDT
Thank you for detailed reply.  I will check my stems.  I have to take my sunflowers down in mid September because their bed is being renovated, but I will save the stems to dry.

My bees disappeared a week or so ago.  I still have quite a few plants for them, including fresh cone flowers to be planted in a month once my garden expansion is done.  I was having 5 - 6 bees on some of my sunflowers, but now none.  Where did they go?  Why did they go?

Thanks!

Andrea

Sent from my iPhone

On Aug 24, 2022, at 10:23 AM, Ask Extension <<personal data hidden>> wrote:


The Question Asker Replied August 26, 2022, 10:28 PM EDT

Hi Andrea!

Once the sunflowers begin to go to seed, the bees will seek pollen elsewhere. To encourage bees and other pollinators to stay in your garden, plant a diverse array of plants that have staggered blooming periods. Some late season blooming native plants like New England Asters, Goldenrod, and Anise Hyssop will do the trick!

Jamie

Answered by the Home and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied August 29, 2022, 10:55 AM EDT

Loading ...