Damage to plants #566451 - Ask Extension

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Damage to plants #566451

Asked June 02, 2019, 9:12 AM EDT

Can you identify the cause of the yellowing and withering of this swamp milkweed plant? It is the only plant affected so far in this area of the garden and the other swamp milkweed plants that are in different locations do not have this damage. The dead stem started out getting yellow and in about 48 hours was dead. I removed that stem from the plant. Thank you.

Baltimore County Maryland

Expert Response

Please send us photos of the plant and the site, around the base, and affected stems/foliage so we can see what you may be dealing with.  Also, give us more more information, how old is the plant, site conditions, etc. 

Marian
Thank you for your quick reply. The swamp milkweed is in a small area that get afternoon full sun at least 
6 hours per day. The area does have a clay base with good quality soil about 6-8 " on top. The large plant is one year old and was purchased from a reputable local nursery. Photos IMG 1298 and IMG 1309 are of the soil and stems of the plant. IMG 1300 is the healthiest looking stem beginning to yellow.
I will send several more photos in following emails.
The Question Asker Replied June 03, 2019, 3:50 PM EDT
IMG 1306 and 1307 are smaller plants that I winter planted and transplanted in early May. IMG 1319 is another stem that is yellowing.
I will send one additional response with photos.
The Question Asker Replied June 03, 2019, 3:55 PM EDT
IMG 1310 and 1311 show the top portion of the most affected stem.

I hope that I didn't information overload you. Thank you for your assistance. At this time all other flower, herb and vegetable plants appear to be unaffected. I did send a question regarding a Joe Pye plant that was withering and it was determined to be herbicide exposure. We live in a retirement community and commercial lawn service and lawn and garden care is contracted to outside companies.
The Question Asker Replied June 03, 2019, 4:00 PM EDT
This looks like spider mite damage. Spider mites are very tiny pests related to spiders. They suck the chlorophyll from the leaves, resulting in yellow or white spots called stipples. Spider mites tend to be worse in hot, dry areas. Some of your plants are near a brick wall where they will get radiant heat from the building, potentially exacerbating the problem. Take a look at our webpage about spider mites and options for managing them. https://extension.umd.edu/hgic/topics/spider-mites-flowers-and-groundcovers

Christa

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