By Guest Author Kristen Pullen of Bushel and Berry.
What’s not to love about container gardening? It brings greenery into spaces that desperately need it, it lets those of us without yards still enjoy plants, and it has broadened the use of traditional landscape plants through new breeding specifically for smaller spaces. But when the days grow short, the leaves start to fall, and you feel that tell-tale temperature dip letting you know winter is coming, what can you do for your potted friends?
In this article, I’ll be talking specifically about care for containerized blueberries, but many of these tips can be applied to other Genera as well.
Berries For Containers
At home, I keep three containers of blueberries. Blueberries are pretty hardy plants; on average they survive USDA zones 3–10. Be sure to always check the plant tag to find the exact hardiness zone of the variety you’re purchasing.
Preparing To Overwinter Your Berries
The first thing you’ll want to do is to stop any fertilizer you’ve been feeding your plants. Fertilizer encourages new growth, but you want to get your plants ready to go dormant. It’s best to cut this off by early- to mid-September, depending on your zone. Warmer climates can wait longer, cooler climates can stop earlier.
Many blueberries are deciduous, meaning they will naturally lose their leaves as the temperatures drop. You’ll want to leave your containers alone at first so that the plants naturally go dormant through the fall. Keep an eye on your 10-day forecast. If you see freezing temperatures approaching or an extreme temperature fluctuation expected, (something like daytime temperatures of 70 degrees Fahrenheit plummeting to 30 degrees Fahrenheit overnight) then you’ll want to start the overwintering process.
How To Overwinter Berries In Containers
What we’re looking to achieve is protecting the roots inside the pot. When berries are planted in the ground, the roots have insulation, but the exposed sides of the pot make for a harsher winter climate for container plants. The following solutions can help:
- Group containers together and move them closer to your house. This includes taking down any hanging baskets you are using, as they are more susceptible to cold winds suspended in the air. The foundation of the house will provide protection from chilling winds, just be sure that you don’t place your plants under a gutter or any other runoff that will have them soaked with water.
- Wrap your pots with burlap. This provides extra insulation for the roots inside the container.
- Add an extra layer of mulch to the top of the pot. Combined with the burlap, this provides insulation on all sides of the root ball.
- If you have extremely harsh winters, move your containers inside an unheated garage or basement. Keep your containers inside until the threat of the last frost has passed (typically early spring).
When to Water Dormant Berries
Throughout the winter, you want to make sure the soil in your containers stays moist, but not soaked. Plants need less water during dormancy than when actively growing. Water your plants during the day when the temperature is above freezing and with adequate time for the water to soak in before the temperatures freeze again at night. If your containers become covered by a layer of snow, leave it be.
This is extra insulation for your plants.
Preparing Your Berries For Spring
As spring approaches, keep your eye on the 10-day forecast again and look up the frost-free date for your USDA zone. Once the temperatures are safe, you can move your containers back to your desired space and remove any wrappings. As the temperatures warm up, you should start to see green buds forming along the stems of your blueberry plants.
Once you see buds over the majority of the plant, it’s a good time to look for any dead stems that aren’t budding up and remove them. Use a pair of clean pruners and cut the dead stem out at the soil level. This type of pruning increases air flow which in turn decreases the likelihood of foliage diseases.
Author’s Bio: Kristen Pullen is brand manager of Bushel and Berry® and Woody Ornamental Plants portfolio manager of Star® Roses and Plants. She completed her Bachelor of Science in Biology at Rider University. After college, she took an internship position at Longwood Gardens in Chester County, Pennsylvania. Kristen has been with the new product department at Star® Roses and Plants since 2011. She previously managed domestic and international trialing of woody plants before accepting her current role where she coordinates the development, launch, and market evaluation of all new trees, shrubs, and edible plants. To learn more about the Bushel and Berry® Brand, visit our website.