Gwinnett Hardiness Zone & Frost Dates

Hardiness Zone
The purpose of the USDA Hardiness Zones map is for growers and gardeners to determine which plants will tolerate the area’s climatic conditions. The map’s basis is the minimum extreme temperature that can potentially occur, which is divided into 14 separate zones across the country. Gwinnett County is in Zone 7b, meaning that the winter temperatures could drop to five to 10 degrees, although the occurrence is quite rare. Zone 7b is too far north for some plants, such as citrus plants, which prefer the hardiness zones in Central and Southern Florida. Georgia’s coastal counties are in zone 8b, meaning the temperature could drop to as low as 15 to 20 degrees. Plants that thrive on the coast and the rest of South Georgia, such as oleanders and sago palms, could suffer in our zone during an extreme cold weather event. Most plants for sale at local garden centers have USDA Hardiness Zones on their labels. Make sure your purchase ones that are adapted to Zone 7b.

First and Last Frost Dates
In addition to knowing your hardiness zone, every gardener should know the average frost dates. These dates are the key to successful planting. Just look at the instructions on a seed packet or plant tag. “Plant in spring after danger of frost has passed.” Or, “Plant six weeks before the first frost in fall”. Frost dates are also important when it comes to pruning and executing pest control measures.
Average frost dates are based on historical weather data and may or may not hold true every year. In the spring, planting instructions often refer to the average date of the last frost, which is the date on which the last frost has already occurred. Remember – this is an average. This means that if you plant after this date, there is a good chance there will not be any more frosts and frost-sensitive plants should be safe outdoors. Still, you should watch the weather forecasts and be prepared to provide protection … just in case.
The first frost date of autumn helps you time fall plantings, when to bring your tender houseplants indoors and when to harvest tender vegetables. Again, the first frost date is an average and frost may occur before then. It is best to keep an eye on the weather and be prepared.

Timothy Daly, University of Georgia Extension Gwinnett County | Agriculture and Natural Resources County Extension Agent
Ann Langley, Master Gardener Extension Volunteer, Class of 2017

Pandemic Gardening

We asked our members to tell us what they’re doing in their own yards during this pandemic.  Scroll down to read their stories and see the pictures they sent.

Since many people are experiencing job loss and food insecurity during the pandemic, St. John Neumann Catholic Church hosts a food bank to provide canned and frozen foods to those in need. To add a fresh food component, the Creation Care Team, led by Master Gardener Extension Volunteer Susan Varlamoff, sponsored two workshops on vegetable and fruit gardening for fellow parishioners. Gwinnett County Extension Agent Tim Daly, who is a member of the parish, conducted the workshops.

Lettuce, kale, broccoli, cabbage, and peas were planted in raised beds to provide fresh vegetables for the pantry. Twenty-five bags of lettuce have been harvested so far.  A fig tree, blueberry bushes, and a blackberry vine were planted to supply fresh fruit next year. About a dozen people attended each workshop wearing masks and practicing social distancing.

Mary Kistner Nature Center in the Snellville area is a GCMGA and MGEV garden restoration project which received a 2020 GCMGA grant. 

In the top photo, volunteers are installing plants in this year’s grant area which is located at the entrance to the woodland garden in back of what was Mary’s home.  The emphasis of the project was on adding native plants that combine to form a plant community in an area with very poor soil, lots of rock and even more deer.  The second picture shows the orchard of American chestnut seedlings planted two years ago.  These plantings were done in collaboration with a nationwide project of the American Chestnut Foundation to develop strains of American chestnut trees that can withstand the soil fungus and disease that have nearly wiped out this species in the eastern U.S. The third picture shows a pathway leading into the woodland garden at the Kistner Center. 

This garden was begun by Mary Kistner years ago. In the center of the area is Mary’s Secret Garden where her ashes are scattered.  The following wonderful group of MGEVs provide willing hands and valuable expertise at the Kistner Center: Carol Hassell, Mary Ann Maher, Karen McGinty, Glenda Patterson, Lori Prosser, Martha Whitman, and Becky Wolary.

Volunteers are installing-plants purchased with GCMGA grant funds

Volunteers are installing-plants purchased with GCMGA grant funds
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We heard from Inday B that they created two flower gardens, one in the back of the sunroom and in the front porch walkway. We also finished the sidewalk leading to the arbor and back gate. These we accomplished with the help of our two wonderful high school grandsons during early spring and summer. We hope you enjoy.

Susan V told us that Master Gardeners, along with a passel of St. John Neumann parishioners, care for creation in the church gardens. Each Thursday, a dozen or so gardeners pull up at 8:30 am to beat the heat to begin work. They unpack hand tools, wheel-borrows and knee pads to pull out weeds, lay down newspaper and cardboard as a barrier against future weeds and pile wood chips on top. They deadhead plants, cull over-crowded plants, water, label horticultural specimens and indulge in a few ripe blueberries. We are following the Action Plan written for Pope Francis’ environmental encyclical Laudato Si in which he calls on the people of the planet to care for the earth and one another. One chapter in the Laudato Si Action Plan recommends using sustainable practices in managing the landscapes surrounding the churches. They include establishing a pollinator garden to attract bees and butterflies whose numbers are down more than thirty percent. Using plants native to the local ecology to draw indigenous wildlife, and foregoing pesticides to avoid harming animals, plants and even humans. Besides benefiting nature, gardening give us the opportunity to socialize with one another and catch up on one another’s news during the pandemic since many of us are staying close to home. Out in the fresh air, we feel invigorated as we exercise and enjoy each other’s company while following Pope Francis call to care for creation and each other.  

Susan Varlamoff, co-author Laudato Si Action Plan, author, Sustainable Gardening for the Southeast

Our plans to host the annual GCMGA April plant sale had to be cancelled due to the pandemic and stay at home guidelines.  After much deliberation, it was decided that a fall sale wasn’t viable and we’d delay to 2021 – BUT – that left loads of plants that members had been fostering for the April plant sale. On Saturday, May 30, many Gwinnett Master Gardeners picked up plants at Community Garden of Snellville parking lot. A great crew put together orders from the plants that had been potted up for the canceled April sale. It was wonderful that the City of Snellville let us use the parking lot for this event. Thanks to Susan Kosenka (who gallantly took on creating the order form and organizing the orders), Wes and Lucy Nettleton, Virginia Schofield, Susan Varlamoff and Linda Bolton, {who joined us to sell Garden Tour tickets}, and Lynda Pollock. We really appreciate everyone who shared their plants and made purchases. Leftover plants are making their way to Vines and the Community Garden of Snellville. 

Cars arrive to pick up plants and Linda's working that line

Cars arrive to pick up plants and Linda's working that line
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Marcia L told us …. We have a wooded wetland for our back yard. There was an old footbridge across the creek, which had gotten pretty rickety, so we decided to replace it ourselves this year. We are not terribly “handy” (taking the old one apart gave us guidance on how to build the new one), but it kept us busy and outdoors during the entire stay-at-home period!

Bridging the isolation gap with nature

Bridging the isolation gap with nature
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Marcia and her husband replaced the old footbridge across the creek

Lynda P responded with pictures and an account of what’s she’s doing this May saying….

Front yard pollinator meadow is coming into its own. Created a raised bed veg garden also in the front yard. We’ve cleared privet, honeysuckle, and English ivy out and can now get down to the creek and are planting a native woodland. We’re enjoying sitting by the creek and communing with Harold the great blue heron. All the clearing was done by hand including my sweet sons, who’ve been off work,  and Bob the Master Gardener’s Assistant. You’re welcome to come visit. Cheers!

Beauty in pollinator meadow

Beauty in pollinator meadow
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