Grow Blueberries In Pots To Help Create The Perfect pH And Moisture Levels
Ed is a horticultural therapist, professional gardener and writer. Ed has a BSc in Occupational Therapy from Coventry University and a Diploma in Social and Therapeutic Horticulture (DipSTH) via Thive, the RHS and Pershore College. Ed runs a community kitchen garden in West Sussex, where he leads horticultural therapy sessions.
Reviewed By COLIN SKELLY
Colin is a Horticulturist and Horticultural Consultant with experience in a range of practical and managerial roles across heritage, commercial and public horticulture. He holds the Royal Horticultural Society’s Master of Horticulture award and has a particular interest in horticultural ecology and naturalistic planting for habitat and climate resilience.
Contributions From LORRAINE SUMMERS
Lorraine has worked with camellia plants for over 40 years. Based in Wimborne (Dorset), the nursery has various camellia species, cultivars and hybrids for sale and has links to the International Camellia Society.
IN THIS GUIDE
Blueberry shrubs not only produce delicious fruit but look great when they flower in spring and their foliage turns red in the autumn.
Originating from North America, blueberries are well suited to our climate here in the UK, especially when grown in pots and containers.1The Blueberry: An American native. (2021, October 27). Berkeley Horticultural Nursery. Retrieved March 13, 2023, from https://berkeleyhort.com/gardening-suggestions/the-blueberry-an-american-native-2/
Are Blueberries Suitable For Pots?
Absolutely!
Blueberries have certain soil and climatic requirements that need to be met in order for them to thrive and produce the delicious fruit they are grown for.
“My garden has slightly acidic soil but a low enough pH for blueberries to thrive,” says Colin Skelly, a Professional Gardener & Horticulturist with over 13 years of experience.
“I grow my blueberries in pots so that I can create the perfect pH and moisture levels using ericaceous compost.
“They are moisture-hungry in summer, particularly in prolonged dry spells, so a water butt would be a good idea if you don’t already have one.
“This has the added bonus of collecting pH-neutral rain water.”
Growing blueberries in pots is ideal as the soil can be chosen to suit their needs and the planters moved to protect them from the worst of the winter weather.
Sourcing Ideal Containers
There are many different varieties of blueberry available to grow here in the UK, with ‘Blue Crop’ and ‘Duke’ perhaps being the most commonly grown.
The eventual size of blueberry shrubs can differ hugely depending on the variety, ranging from dwarf varieties that grow up to 1m to large bushes growing as high and wide as 3m.
When choosing a container to grow blueberries in, make sure it will be able to accommodate the shrub’s eventual size and root system, but as a general rule, a 30cm diameter pot is the minimum for a newly planted shrub.
“You can grow blueberries in containers, but as small plants, they don’t like to be overpotted,” says Lorraine Summers, the owner of the specialist blueberry retailer Trehane Nursery.
“Plant into a container that is 2-2.5 times the volume of the pot your plant is in now.
“Ensure that the pot has good drainage holes and cover the holes with coarse gravel to prevent clogging with compost.”
As mentioned, blueberries require free-draining soil, so any container used will require adequate drainage holes to allow any excess water to escape freely.
Remember that blueberry plants prefer moist, but well-drained ericaceous soil with an acidic pH.
Potting Up Blueberry Plants
Water the blueberry plant thoroughly before planting and half-fill the chosen pot or container with ericaceous compost.
Remove the plant from its pot, place it in the container and backfill it with more compost, gently firming it in as you go.
Ensure that the blueberry is planted at the same depth it was previously and water in well.
“Ericaceous compost must be used and potting up is done every two or three years until the final container can be used, which should be of at least 50 litres capacity,” says Lorraine.
How Many Can You Plant Per Pot?
It is advisable to only plant one blueberry plant per pot or container, as they develop a tightly packed fibrous root system in the space they are given and do not like to be overcrowded.
Even though many blueberry varieties are described as self-fertile and will produce a good crop, growing two or more varieties nearby can increase not only fruit size, but yields as well.
Potted Blueberry Care
Watering
When it comes to watering blueberries, rainwater is the preferred choice as tap water can raise the pH of the soil.
Blueberries require moist, but not wet soil and will need watering regularly, especially after planting and during the summer months when they are actively growing.
Feeding
Blueberry shrubs can be hungry feeders and certainly benefit from an ericaceous liquid fertiliser applied during the growing season from April to September.
Overwintering
Many blueberry varieties are fully hardy, but some are not and even those that are can suffer from the extremely low temperatures and wet conditions of winter.
One of the many benefits of growing blueberries in containers is that they can be moved undercover or to an unheated greenhouse to avoid the worst of the winter weather.
Re-Potting
Blueberry shrubs can need re-potting either due to outgrowing their current container or when their soil needs refreshing, which can be every 2-3 years.
If the blueberry’s roots are visible through the container’s drainage holes this is an indication that it needs re-potting into a larger pot, which can be done in either spring or autumn.
To re-pot, remove the blueberry from its current container by squeezing the pot sides or if necessary, sliding an old knife down between the pot and the soil.
Inspect the roots and if root-bound or severely congested, gently tease out some of the roots.
Fill the bottom of the new container with fresh ericaceous compost and place the plant ensuring it is at the same depth as it was previously planted.
Backfill with compost and water thoroughly.
If re-potting becomes difficult due to the size of the shrub, then it can be top-dressed instead, which is when the top 5-7cm of compost is replaced each year to replenish any lost nutrients.
Protecting Fruit
As with blueberries grown in the ground, container-grown shrubs will need their fruit protected from any birds.
As soon as the berries start to turn blue, fleece or fine netting can be placed over the shrub to form a barrier against pigeons and blackbirds who can strip the berries bare if they are not protected.
The fruits are ready to harvest when they have fully changed colour and there is no hint of green left.
Pruning
Whether grown in the ground or in containers, blueberry shrubs can benefit from an annual prune carried out when they are dormant in winter.
New blueberries don’t need much pruning, apart from removing any wayward stems or shortening them to encourage branching.
From the third year onwards, annual pruning involves removing any dead, diseased or rubbing branches.
As the shrub matures, up to 25% of the oldest and thickest stems can either be pruned back to a strong shoot lower down or removed at the base, to encourage new growth which will fruit the following year.
