This is the question I’ve frequently been asked as a grower. A simple yes or no is what many people want, but the answer is quite complex. I usually respond with “it depends on many factors”.
Overall Plant Preferences
Camellia sinensis can produce growth for harvesting in 80-90°F temperatures. When dormant, they could tolerate mid 20’s with precautions.
Your location will be a big factor in determining if Camellia sinensis can grow outdoors during cold weather. You can refer to the climate zone map on page 12. Usually, zones 8 and 9 are well suited for growing tea. When you move to the cooler climate zones of 7 and 6, then you have to take into consideration a few more factors. Even within a particular climate zone, you could have some variances. For example, our home is on the coast in zone 8b but 70 miles inland, in the same climate zone, we can see a 7–8-degree temperature difference. In January of 2018, it was 18°F degrees in Savannah GA and back at the farm it went to 10°F. Using the zone map as a basis is ok but rely on your experience with temperatures for your own area. It may be warmer or cooler than normal for your particular locations.
Planting Location & Preferences
Avoid full sun in colder climates. An overstory of evergreen shade trees can provide winter protection from sun and wind. Planting next to a building, fence, or hedge can offer cold winter wind protection.
Degree and Length of Cold
Tea plants should be able to handle cold of 20-25F for short periods. Prolonged cold or ground freezing could damage plants. This depends on the other factors listed below.
Age Of the Plant
Younger and less established plantings will not tolerate cold temperatures as well as larger more mature plants. 2–3-year-old plants with established root systems are better equipped to handle cold. Seedlings traditionally have shown more cold tolerance than plants produced from cuttings.
Health Of the Plant
The health of your tea plant will be a factor in a plant’s ability to tolerate the cold. Poor health, dehydrated, or under-nourished plants will not be strong enough to pull through the stress of extremely cold weather. Make sure your plant is well-nourished and well-hydrated.
Time of Planting
When you plant a camellia, it needs to grow out into the surrounding soil to establish a bigger and stronger root system. A larger root system means it can handle stress better. For this reason, spring planting is widely recommended for colder climates. This gives the plant extra time to get established before cold weather sets in. But don’t think that it gives you a free pass on winter weather. In the first year or two, you need to add protection and any other year that you have an unusual cold.
This could be in the form of greenhouses, cold frames or frost blankets. Avoid white plastic sheeting which can burn foliage when the sun comes out.
With plastic, you want to use a barrier between the plant and plastic like a sheet. Plastic touching the plants could transmit the cold right to the leaf.
Snow in Georgia in 2018 on newly planted tea. We went to 10°F and had a little damage on some of the plants. It was only freezing for a day or two. In 2022 we had an artic blast that brought in below 20°F temps for almost 5 days and we had significant damage to some of our plants that were fine in the first freeze in 2018. The longevity of the cold temps played a part in latter damage.