About St. Mary's County Master Gardeners

Our Vision

We envision a healthier world through environmental stewardship.

Our Mission

We support the University of Maryland Extension (UME) mission by educating residents about safe, effective and sustainable horticultural practices that build healthy gardens, landscapes, and communities.

Our History

The UME Master Gardener Program began in 1978 as a means to extend science-based knowledge to the general public by providing horticultural and pest management expertise to help protect and improve Maryland’s natural resources. Today, this popular program can be found in 20 Maryland counties and Baltimore City. 

UME Master Gardeners are volunteers who combine their love of plants, people, and the environment to help residents in their communities solve problems and make environmentally-sound decisions.  

St. Mary’s County Master Gardeners

St. Mary’s County Master Gardeners do a lot to help our community. We host Ask A Master Gardener Plant Clinics where we answer the public’s horticulture questions, conduct Bay-Wise site visits to help educate residents about how to make their landscapes more friendly to the Chesapeake Bay, do many presentations on pollinators, native plants, and other horticulture topics, plus so much more.

Master Gardener Programs

Plant clinics are an opportunity for Master Gardeners to help answer the public’s horticulture questions. We are doing them virtually during covid-19. Please see our Facebook page for Facebook live Plant Clinics and check out the St. Mary’s County Library’s calendar of events to get the link to attend one of our virtual plant clinics!

Before and hopefully after covid-19, we are at the local libraries, farmer’s markets, and more to host plant clinics. People bring us horticulture samples (like plants, insects, tree twigs, etc), pictures of horticulture samples, or just ask us questions. We help answer their questions.

Check back for more updates about plant clinics and when we can return to doing them in person!

Library Calendar of Events

St. Mary’s County Master Gardener Facebook Page

  • What is Bay-Wise?

Bay-Wise is a program designed to help Maryland residents learn more about horticulture and landscape practices that are wise about the bay’s health. Maryland Master Gardeners educate Maryland residents about bay friendly practices through presentations, demonstration gardens, one-on-one consultations, home visits, and more. We have also created a “Bay-Wise Yardstick” to help residents see what is and is not Bay-Wise.

  • How Do I Get My Home Landscape or Vegetable Garden Certified as Bay-Wise?

Interested in making your landscape more Chesapeake Bay Friendly? Follow these three steps:

1. Download the appropriate MD Yardstick along with an application

2. Complete the Bay-Wise Maryland Yardstick Application
3. Contact the St. Mary’s County Master Gardeners to sign up for a site visit for certification.  Do not submit your completed Yardstick and application before you contact your local Master Gardener program. 

Once a 'Bay-Wise trained' Master Gardener certifies your home landscape you will receive a small sign to display in your landscape and a certificate. Even if you do not have your landscape certified, you can still do plenty to reduce pollutants going into the Chesapeake Bay by following the suggestions in the Bay-Wise Yardstick.

If you are interested in learning more about the Chesapeake Bay and how our behaviors effect it, please check out the Watershed Stewards Program 

St. Mary’s County Master Gardeners educate St. Mary’s residents about pollinators. Pollinators are very important and proper gardening methods can reduce any harm to them. We have many pollinators in St. Mary’s County such as butterflies, bees, and more! 

Many pollinators prefer native plants and prefer native plants. We have many demonstration gardens around the county that have many pollinator friendly plants that grow well in St. Mary’s such as milkweed, joe pye weed, zinnias, and more! 

Check out our upcoming events page to see when we are having our next educational event on a pollinator related topic!


St. Mary’s County Master Gardeners educate St. Mary’s residents about composting. We do this through educational presentations, demonstration areas, and more.

Composting is a good way to help reduce waste going to landfills. It is a way put waste to good use! Compost often contains a lot of nutrients that plants need to grow.

Check out our upcoming events page to see when we are having our next educational event on a pollinator related topic!

For information on agriculture please go here 

The Grow It Eat It program is designed to help educate Maryland residents about how to grow and then eat their own food! The St. Mary’s County Master Gardeners have educational presentations, demonstration gardens, and more on how to grow and eat your own food!

There are a lot of plants that produce food that we can grow in St. Mary’s. Some examples are tomatoes, greens, okra, eggplant, squash, rosemary, sage, oregano, thyme, blueberries, raspberries, and more!

Check out our upcoming events page to see when we are having our next educational event on a Grow It Eat It related topic!

For information on nutrition education 

Family Consumer Science nutrition education

SNAP-Ed nutrition education

St. Mary's County Master Gardeners love native plants! Native plants are plants that were growing here before European settlement. Master Gardeners help educate Maryland residents about how to grow native plants and why they are important.

There are many plants that are native to St. Mary’s County including milkweed, joe-pye weed, andropogon glomeratus, etc… Many species of pollinators co-evolved with native plants and depend on them. We grow many native plants in our demonstration gardens around the county. Check them out at different times of the year to see how pretty and beneficial to our local ecosystem they are!

Check out our upcoming events page to see when we are having our next educational event on a native plants topic!

Become a Master Gardener

Why become a Master Gardener?

  • Master Gardeners do a lot for their counties! We help educate local residents as well as maintain demonstration gardens to help beautify our county. By joining the program, you'll have the opportunity to learn new gardening skills as well as hone your existing skills. You'll also learn how to solve gardening problems, and be able to teach others to do the same. Best of all, you'll meet new people who enjoy gardening just as much as you do!

Who can become a Master Gardener?

  • Any Maryland resident, 18 years of age or older, who likes working with people and plants and has a thirst for knowledge.

What do Master Gardeners do?

  • Master Gardeners help educate local residents about various horticulture methods that are safe, effective, and sustainable. We do this through presentations, workshops, demonstration gardens, social media, and more.

How to become a Master Gardener?

Steps to Become a Master Gardener

Step 1

Determine when the Master Gardener Basic Training will be held in St. Mary’s County by visiting our When is the next training webpage. Basic Training classes are typically offered once a year or every other year in St. Mary’s County.

Step 2

Contact the Master Gardener Coordinator  (Mariah Dean, email is and phone is 301-475-4120) to learn more and receive an application package.

The fee to enroll in a Master Gardener Basic Training course is $165. This fee pays for the mandatory Master Gardener Handbook, class materials, and covers additional costs to support the program.

Step 3

A Master Gardener Trainee is required to attend at least 75% of the Master Gardener Basic Training classes and pass the final exam. Master Gardener Trainees are taught about a variety of horticultural subjects by specialists, educators, and other horticulture professionals. Topics may include:



Diagnosing Plant Problems



Integrated Pest Management (IPM)


Lawn Care

Vegetable, Fruit, & Flower Gardening

Organic Gardening

Pesticide Use and Safety Precautions

Soils and Fertilizers

Tree and Shrub Care

Step 4

Once a Master Gardener Trainee has completed the Master Gardener Basic Training and the passes the final exam, they become a Master Gardener Intern.  Interns must complete at least 40 hours of approved volunteer service before achieving the status of Master Gardener.  

To remain an active Master Gardener, each calendar year individuals must complete

1) a minimum of 20 hours of approved volunteer service, and
2) a minimum of 10 hours of approved continuing education.

Continuing education hours may be completed through classes, webinars, seminars and other educational activities offered by UME, plant societies, botanical gardens and arboreta, colleges, nature centers, etc.

When can I become a Master Gardener?

  • St. Mary’s County typically offers basic training classes either once a year or once every other year. We usually offer our classes in the winter/spring timeframe. You can sign up to receive updates about when the next one is or check back on our website for future class dates.

Where do I have to go to become a Master Gardener?  

  • During covid-19 we have been continuing most of our activities virtually, so you can become a Master Gardener at home! Before covid and hopefully after covid, we will return to having basic training classes at the St. Mary’s County Extension office Leonardtown, Maryland. We have various places that we do Master Gardener activities such as the county park sign gardens, local organizations like Sotterley, St. Mary’s County Library, and more.

University of Maryland Extension

26737 Radio Station Way, Suite E-2

Leonardtown, MD 20650

Next Master Gardener Training

The Master Gardener Basic Training class is offered every other year in St. Mary's County. Our next scheduled session is spring 2024. Please check back here for updates about specific dates. Please note that with the new background check policy, applications must be submitted no later than 45 days before the start date of the class. 

Home Gardening Monthly Tip from MG's

Check here for a monthly tip from a Master Gardener!

Upcoming Events

The Vine Newsletter

Additional Resources

Learn about MG upcoming events, gardening and pest tips, and education opportunities.


The Home and Garden Information Center (HGIC) develops and delivers science-based, sustainable gardening and integrated pest management education for better human and environmental health.

Ask Extension Question, Mark, Punctuation, Symbol
Maryland Certified Professional Horticulturists answer yard and garden questions. Find answers to many common questions on our website.

Ask Extension