In Containers

Container:

This will be long term and bushes can be 3’-5’ tall and as many feet around. Choose a large container. Tub or wine barrel size is good. Make sure the pot has drainage holes. blueberries don’t want to sit in water. Wheels can be a good idea if you want to easily move the pot. Plastic or wood are good materials and slightly lighter and less breakable than clay. You can always start in a smaller pot and re-pot each year into bigger pots (the bigger the bush the harder this is to do).

Soil:

Blueberries like acidic soil and naturally grow near pine trees. For your soil purchase pine mulch. It should look like it is chewed up and partially broken down like compost. Avoid bark nuggets that look like they were just stripped off the tree. Fill your container with pine mulch to 2” from the edge of the pot. As the bark breaks down over years you can add more to the container.

Sun:

Blueberries like full sun. Partial sun will be okay if that is all you have.

Water:

Keep the mulch moist. A bigger container will hold moisture longer and will mean you won’t have to water as frequently. Watering all depends on your location (US climate and microclimate of your yard).  A good test is to stick your finger in the mulch, if it is still moist 1-2” down you are okay. If it is dry it is time to water. You want you mulch to be moist not sopping wet. Also, if the mulch dies out completely it is hard to re-wet it. Containers dry out faster than the soil in the yard so keep an eye on your pot. If you leave for an extended time it will be beneficial to move the pot to a shady spot to keep evaporation to a minimum.

Fertilizer:

Osmocote is a good slow release fertilizer. Buy Osmocote Flower and Vegetable. Sprinkle 2 T of osmocote on top of the mulch in early spring (early flowering when day temps are in the 60’s and 70’s (depending on geography this is March to April). Then sprinkle 1 T on top the mulch April to May….about 2 months after your first application. Again put 1T of osmocote on the bushes after harvest (July-ish). This will promote new shoot growth and bud set for next year. You could also use an azalea/rhododendron fertilizer. But be careful to not over fertilize…the salts can burn the roots and kill your plant.

Pruning:

If your bush is actively growing by year three it will need to be pruned and then every year after that. It is best to prune in the winter when they are dormant before they flower. A good time to prune is February in NC and March in northern locations. Cut the branches out with pruners close to another stem or the Crown (center of the plant). You want to remove any branches that cross over other branches. You also want to open up the center to let light into the fruit. If there are dead branches these should be cut out as well. The fruit forms on the top 8-12” of a branch. Over-cropping is a problem and can affect the bush for many years so it is important to prune each winter. It is good to have a nice mix of old and new “canes” or branches. Old canes are thicker and have rough bark….new canes tend to be smooth and red or green in color.

Flowering and fruiting:

Flower buds form the summer before fruit production. Right after a crop is picked the bush will put on leafy growth and set buds before going dormant for the winter. Flower buds form on the top 8-12” of a branch. They are visible and are about the size of a small pea. As the weather warms the buds will swell in the spring. From each bud multiple flowers will emerge. When visible buds form in the spring it is important to watch the weather. If a frost is expected it would be beneficial to cover your bush with a sheet to try and protect the flowers from temperatures below 32. Cover flowers where you can see them starting to separate…stage 3 or 4 to stage 6 in the above graphic. From flower pollination it is about 50-60 days to ripe fruit depending on cultivar and weather.

Overwintering:

In NC and south you don’t need to do anything special. The leaves will turn color in late fall, fall off and the plant will go dormant. In March it should come back and flower and then leaf out. During the dormant period it will take up less water so that should be less frequent and may not be necessary at all depending on rainfall. In the north you should probably push the container up against the house for heat. You may even need to cover the bush with burlap.

https://hort.uwex.edu/articles/growing-blueberries-containers

http://www.hort.purdue.edu/ext/HO-65.pdf

http://ohioline.osu.edu/hyg-fact/1000/pdf/1422.pdf

http://www.fallcreeknursery.com/gardeners/gardeners_tips

https://www.rhs.org.uk/advice/grow-your-own/fruit/blueberries