Roots, Shoots, Fruits & Flowers: Yellow Butterfly, Horsetail Scouring Rush & Fertilizer Label

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A yellow caterpillar feeding flowers. Photo: Christy Frederick, Master Gardener, Pineville, LA

Yellow Butterfly

Sometimes readers will share some positive emails and pictures. Christy of Pineville shared this email and images from late 2022, “I was encouraged…to find quite a few Cloudless Sulphur caterpillars on yellow cassia in my yard. These butterflies are common, but I have never noticed these [caterpillars] before! Yay! They are interesting caterpillars and eating yellow flowers not the foliage.”

There are a few times when tolerance of some damage will reward a gardener with a pleasant surprise like a beautiful caterpillar. Evan Cole, an entomologist with the US Forest Service, shared this information about this butterfly, “The sulphur butterfly, often known as the cloudless sulphur butterfly, is a large yellow butterfly found throughout most of the mainland United States. It is most common in the eastern United States and southern portions of the western United States, but it has been spotted as far north as Canada.”

Cloudless sulphur butterfly.

A cloudless suphur butterfly. Photo: Christy Frederic, Master Gardener, Pineville, LA

Horsetail scouring rush.

Horsetail Scouring Rush. Photo: Silas Cecil, LSU AgCenter

Horsetail Scouring Rush

Silas Cecil, 4-H Agent & Parish Horticulture Agent in LaSalle Parish, sent this email about a strange plant, “A gentleman brought this to me yesterday at church. I do not know if it is a broken-down Field Horsetail Rush or Scouringrush.

[It has] round stems, joints, and no leaves. [It] might not matter, but [is there ]more [information on] how to kill this plant and mitigate the spread.”

Cecil correctly identified this plant. Settlers used this native plant to scour pots and pans so “scouring” is part of the name. This plant is also a living fossil and can be invasive. Weed scientists at the University of Nebraska, Lincoln, conducted trials and reported that Glean® and Telar® were highly effective in controlling this weed.

Miracle Gro plant food.

Miracle Gro(R) fertilizer concentrate Photo:

Fertilizer Label

Kyle asked a thoughtful question, “I was wondering if I use Miracle Gro® All-Purpose liquid fertilizer you mix with water, how long do you have to wait before picking a vegetable. I read online for 2 weeks but I wanted to double check this.”

Kyle took the responsible step of reading the label and then asked his question. AHA was unable to find the 2-week recommendation on the label. However, the Gardening Mentor, an online writer and certified in Home Horticulture and Organic Gardening by Oregon State University, made this statement, “It is safe to eat vegetables grown with Miracle Gro®, but you need to wait at least two weeks after application of the chemical fertilizer, so it is absorbed by the plants. You should also wash the vegetables well before you eat them as the chemicals can irritate the mouth, throat, and skin.”

If you want to contact Roots, Shoots, Fruits, and Flowers, please send your questions and pictures to Keith Hawkins, Area Horticulture Agent (AHA), 337.284.5188 or

“Before you buy or use an insecticide product, first read the label, and strictly follow label recommendations. Mention of trade names or commercial products in this article is for informational purposes only and does not constitute endorsement by Louisiana State University AgCenter.”

“This work has been supported, in part, by the USDA National Institute of Food and Agriculture, Renewable Resources Extension Act Award, Accession Number 1011417.”

5/17/2023 7:42:57 PM
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