It's no wonder bumblebees love Carolina horsenettle (Solanum carolinense), with its similarity to tomato plants and other members of this deadly family. This is not a true nettle but a member of the Solanaceaea family, or nightshades. Its nicknames include bullnettle, devil's tomato or devil's potato. It is perennial.

Tomatoes are another member of this family along with peppers and eggplant. But do not think this is a free vegetable: All parts of this plant are poisonous. You can take your clue from the nickname of its family, deadly nightshade. 

Bumble bees are buzz pollinators, meaning they buzz their abdomen when they land on a flower. This is necessary because the solanaceaea cannot be pollinated by wind or by insects moving pollen from one flower to the next. That accounts for the weed's popularity with bumblebees.

Carolina horsenettle is considered an noxious weed. Although it is native to the southeastern United States, it grows in all temperate climates. Animals are particularly sensitive to the plant's alkaloids. 

There are two main ways to manage this plant, neither of which are a quick fix. Horsenettle reproduces both vegetatively via rhizomes that travel underground and by seeds produced in small, tomato-looking berries. Each berry holds between 40-120 seeds.

If the infestation is not too great you may be able to hand pull these weeds. Be sure to wear substantial gloves because the nettles have small arbs that break off under the skin.

Most sources I have read suggest that herbicides are the most efffective method of control. I would check with your extension office for specific recommendations. I am not qualified to offer that information. You should be able to contact them at extension.osu.edu/lake-county-office

Glad the bumblebees are happy, but you need to think about what would happen if the horsenettle left the edge of the retention pond and marched farther onto your property. It's not called invasive for nothing. 

Here are some resources to teach you more about this weed.

https://extension.tennessee.edu/publications/Documents/W264.pdf  

https://www.inaturalist.org/taxa/52899-Solanum-carolinense#Faunal_associations_and_diseases

I am so glad that was helpful. Here's to fewer horsenettle plants in your world!