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Free Gardening Advice from Extension Experts

Jill is a former Master Gardener and Naturalist who enjoys cooking, abstract painting and stewardship.

Experts throughout the US provide online answers to gardening questions free of charge through the eXtension Ask an Expert program.

The Caterpillar in Our Garden


Two weeks ago, I noticed a large caterpillar stripping the leaves from one of our knockout rosebushes. It wasn't doing too much damage, but I was nervous.

Last year, a bad case of rose slugs had almost killed one of our bushes. Should I be worried?

I took several photos and compared them to pictures in gardening handbooks on our bookshelves.

In some of the photos that I took, the caterpillar wasn't easy to spot. It looked a lot like a mature rose cane!

What Is That?


In other photos, the caterpillar was easy to see, thanks to its size (It was big!) and its fuzzy yellow spines.


After much debate, we decided that it was either a butterfly or moth caterpillar.

I was leaning toward the caterpillar of a Question Mark butterfly (Polygonia Interrogationis), but I wasn't sure.

According to The Life Cycles of Butterflies, Question Mark caterpillars come in a variety of color combinations and patterns. Sometimes they're black with orange spines, sometimes black with yellowish spines and splotches of oranges.

We Ask an Expert


Our caterpillar was black and beige with yellow and reddish-brown spines.

Was it really a Question Mark caterpillar?

We decided to "Ask an Expert."

What Is Ask an Expert?

"Ask an Expert" is a free online service provided by cooperative extensions throughout the United States. Anyone can use the service, both US residents and those residing outside the USA.

The Experts

The experts who answer the questions are cooperative extension staff members, university staff members and volunteers, such as Master Gardeners who have been trained through the extension Master Gardener program in a variety of issues related to gardening through coursework and hands-on experience.

Scroll to Continue

The Master Gardener Program

To find out more about the Master Gardener program, check out the Extension Master Gardener webpage. It provides links to extensions throughout the US in the About section. You can also access free webinars, trending questions and other gardening information there.

Ask an Expert is a service of Cooperative Extensions, which serve as links between state land grant universities and counties. Their goal? To provide services, support and opportunities that help people everywhere improve their lives through education.

The Expert's Response

Because we live in Maryland, I contacted "Ask an Expert" at the University of Maryland Extension website.

I received a response within the promised 48 hours.

According to the responder, she and her colleagues had studied the photos, done some research and believed it to be the caterpillar of a Buck moth.

She advised us not to touch the spines (They sting!) and to allow the caterpillar to pupate, as Buck moths are rather unusual in Southern Maryland.

Thanks, Ask an Expert!

We hadn't intended to move the caterpillar anyway. The damage it was doing to our rosebush was negligible. Besides, we've been trying to attract more pollinators to our yard.

Although I was hoping for a butterfly, I'll also be happy to see the Buck moth's black and white wings fluttering through our yard.

Stinkbug Scare

We also contacted Ask an Expert several years ago when brown marmorated stinkbugs (Halyomorpha halys) first hit Maryland.

I thought I saw one on a tomato plant in our garden, so I sent in a photo and my question. The results were the same: within 48 hours I received a response. (Luckily, it was a regular old stinkbug.)

Ask an Expert gives users the option of making their questions (and Ask an Expert answers) viewable to other users.

The stinkbug on my tomatoes wasn't a marmorated one, thank heavens!

The stinkbug on my tomatoes wasn't a marmorated one, thank heavens!

How You Can Ask an Expert

Extension Ask an Expert

Have a question about something that's going on in your landscape? You can submit your question online at Extension Ask an Expert.

The advice is free, and the online form is easy to complete. It provides boxes for your question title, question and the email address where you would like to receive your answer.

There's also a drop-down box for selecting your state or country, and another drop-down box for indicating your county. You may attach up to three photos as well.

Although your question may remain private, you can click "Share my question on Ask an Expert" to make it and the answer visible to other users.

And, of course, you can read the questions at Ask an Expert (both answered and unanswered) that other gardeners choose to share.

Ask an Expert provides answers to general and specialized gardening questions, including questions about roses. Pictured: Hannah Gordon floribunda rose.

Ask an Expert provides answers to general and specialized gardening questions, including questions about roses. Pictured: Hannah Gordon floribunda rose.

To learn more about real-life gardening problems and solutions, you can scroll through the questions other gardeners have posed on Ask an Expert.

Question Response Time

The answer to your question will arrive to your email with surprising speed.

First, you will receive an automated email that acknowledges you have submitted a question. Then, usually within two business days, you'll receive an expert answer.

Sometimes, the experts at Ask an Expert need more than two days to research the question. Sometimes they forward the question to other experts who are specialists in the question area. If that happens, they will inform you that they need more time.

One user, for instance, asked a question about a snake she'd seen in her yard. Within two days, the experts on duty responded that they could not give her a definitive answer until their snake expert returned from vacation the next week.

Ask an Expert Near You

You may also submit your questions through the website of the cooperative extension in your state or another state. The online form allows you to select your location when submitting a question, including locations outside the US.

The online form at state extension websites looks the same as the one at the Extension Ask an Expert website. The promise is also the same: "expert answers and help from Cooperative Extension/University staff and volunteers from across the United States."

To find the website of the extension in your state, search by the terms "ask an expert," your state name and "extension."

When I googled "ask an expert Florida extension," for instance, the University of Florida Extension's "Ask an Expert" page was my first hit. Googling "ask an expert Oregon extension" yielded a similar result at the Oregon State University Extension website.

Below are links to other popular extension Ask an Expert pages.

Questions You Can Ask an Expert

Lots of questions on Ask an Expert are about tomatoes. Before asking yours, be sure to scroll through the answered questions.

Lots of questions on Ask an Expert are about tomatoes. Before asking yours, be sure to scroll through the answered questions.

Typical Questions

Most questions on Ask an Expert go something like this: "Why is the __________ (tree/shrub/plant/turf) in our garden/yard/flowerbed dying?"

But I've seen other types of questions as well, including questions about

  • houseplants
  • pest damage (deer, squirrel, rabbits, etc.)
  • pest management (squash bugs, stinkbugs, aphids, etc.)
  • plant identification
  • plant diseases (blossom rot, powdery mildew, etc.)
  • snake & insect identification
  • state & local gardening programs for children and families.
A shade-loving white bee balm that isn't prone to powdery mildew.

A shade-loving white bee balm that isn't prone to powdery mildew.

Specialty Questions

Sometimes people ask "specialty" questions about specific types of plants and crops, such as

  • roses
  • tomatoes
  • strawberries
  • fruit trees
  • bonsai
  • native plants.

No matter what question is asked, a thoughtful response is forthcoming. And, as noted previously, if the experts can't answer the question immediately, they will respond to say so.

Get More Free Info from eXtension

For the latest cooperative extension instructional and informational videos, subscribe to the eXtension Initiative channel on YouTube. Access is free, as is the information.

The eXtension Goal: Sharing Knowledge through Technology


© 2015 Jill Spencer


Jill Spencer (author) from United States on July 02, 2017:

@Mike and Dorothy-- They're going to love hearing from you!

Mike and Dorothy McKenney from United States on July 02, 2017:

Wow! The experts are going to wish you hadn't shared this with me! LOL

Jill Spencer (author) from United States on October 04, 2015:

Hi Patricia, Hope you do give Ask an Expert a try. I'm horrible at identifying pests and disease. There are so many variables! It's nice to have someone educated and experienced, sometimes several someones, provide help. Always good to hear from you! Hope you're safe and dry there. We're having coastal flooding here.

Patricia Scott from North Central Florida on October 04, 2015:

Hi Jill This rocks!! I am always having some concern with this or that visitor to my garden or and concerns about flowers and other plants.

I am bookmarking this so I do not lose the info.

Angels are headed your way this early morning


shared pinned g+ tweeted :D

Jill Spencer (author) from United States on August 07, 2015:

Awesome, Kristen. It's a really good, free resource. Thanks for commenting! -Jill

Kristen Howe from Northeast Ohio on August 07, 2015:

Jill, thanks for sharing this hub. I might check out Ask an Expert in the future. Very useful with great photos to share. Voted up!

Jill Spencer (author) from United States on July 16, 2015:

Thanks for your kind words, the share and the vote, thumbi7. Appreciate it!

Jill Spencer (author) from United States on July 16, 2015:

Yes, they do, Thelma. So glad you asked that. I realize my hub makes it sound as if it's a US only service, but it's not.

Thelma Alberts from Germany on July 16, 2015:

That is a great service to the people especially those who love gardening. Thanks for sharing this. I wonder if they also answer questions not from the US. Voted up and useful.

JR Krishna from India on July 16, 2015:

Awesome hub with beautiful photos

I love gardening and appreciate your achievements :)

Voted up and shared

Jill Spencer (author) from United States on July 14, 2015:

Hi poetryman6969. Thanks for you comments! I hope you do give Ask an Expert a try the next time you have a gardening questions. All the best, Jill

poetryman6969 on July 11, 2015:

Very useful and interesting information. I shall have to remember to call the extension agent the next time I have a gardening question.

Love the beautiful photos as well.

Voted up.

Jill Spencer (author) from United States on July 10, 2015:

Hey, Lee. It really is a great resource. No bull. Hope you're having a good summer. It's really hot and rainy here, so much so that we have fungus on plants that usually don't get it. I'm just pruning & pinching to keep good air flow & hoping for the best.

Lee Raynor from Citra Florida on July 10, 2015:

Hey Jill

Excellent info here. I didn't know about the Ask an Expert site but it will come in handy


Jill Spencer (author) from United States on July 10, 2015:

Hi Donna! How did I miss you comment before? You know, I think there is a TV show on PBS associated with the extension. Seems like my husband and I watched it one day. They took call-in questions. Something comparable that's done here locally are information booths at public libraries where MGs field gardening questions once a week. Great to hear from you! Take are, Jill

Jill Spencer (author) from United States on July 10, 2015:

Hi MsDora! Hope you're keeping well. Thanks so much for visiting this hub and commenting. --Jill

Dora Weithers from The Caribbean on July 09, 2015:

Great information. Very helpful. Thank you and Voted Up!

Jill Spencer (author) from United States on July 09, 2015:

Hey Maren, how are you? The program is great and really easy to use. It's as easy as sending an email. Thanks for stopping by, Jill

Maren Elizabeth Morgan from Pennsylvania on July 09, 2015:

Sounds like a wonderful program!

Jill Spencer (author) from United States on July 09, 2015:

Hi Marie. You're right; the MG Program isn't organic. At the risk of being offensive, I think the attitude is fostered by the fact that chemical companies partner with government agricultural programs, providing monies, etc. The attitude toward herbicides & pesticides is a tolerant one by many in the program, and extensions advise farmers and home gardeners on chemical usage. I, however, am organic, no matter how much of an alarmist others may think I am for eschewing Roundup and the rest. You can learn a lot in the program without drinking the Koolaid, if you know what I mean. Take care, Jill

Marie Flint from Jacksonville, FL USA on July 09, 2015:

I receive emails from the Duvall Country Extension Service, but I am reluctant to try the Master Gardener's program, partly out of transportation concerns and because the lessons are not centered around organic growing methods. I realize I'm missing a lot of information.

Voted Useful.

Jill Spencer (author) from United States on July 09, 2015:

Hi Wiccan Sage, I'd so sorry to hear about your accident and that you had to put your life on hold for so long after it. Maybe someday you can do the MG program. I've been in it five years now and, although I'm certainly not an expert, I'm enjoying learning about gardening through the program. And I like to volunteer. All the best, Jill

Mackenzie Sage Wright on July 09, 2015:

Awesome! I was accepted into an MG program once, but before training began I was in an accident that required a year of recovery so I had to turn down the invitation. I never got a chance to go back to that, life had changed... but I highly respect the Master Gardeners out there and the training they go through. It's pretty awesome.

Jill Spencer (author) from United States on July 09, 2015:

Thanks for stopping by, Roberta! Ask an Expert really is easy to use. So helpful!

MsLizzee, you should send your question through the link above to the NC Extension Ask an Expert along with a photo. They might recommend some sort of spray, I don't know. I'd probably just leave it alone or pick the critter off by hand. But that's me. Good luck to you! --Jill

elizabeth from Buncombe County, NC on July 09, 2015:

Hi dirt farmer:

I have a question.I have one 5 foot tomato plant that looks like it's going to have a tomato, but I'm seeing chewing on the leaves. What can I mix up at home that is not toxic and is organic to keep the critter from eating my tomato????

Donna Herron from USA on July 09, 2015:

Hi Jill - thanks for another informative hub! Our state extension office has a weekly gardening program on our local PBS station too. You can call or email the program during their live show and they'll answer your plant and gardening questions on the air. Your readers might want to check out their local PBS station (or cable access) and see if their extension office also has a tv program. Our's offers great information and recipes!

RTalloni on July 09, 2015:

What a great service you've highlighted in this hub! Thanks for sharing this info. It's always been a benefit to have extension services available, but this particular function makes taking advantage of their expertise fast and easy.

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