BLUEBERRIES are one of August’s treats and if you’re not growing a bush, September is the ideal time for planting. Blueberries do very well in the open ground, fruiting faithfully every year and needing little more than a steady supply of water, a mulch top dressing and occasional winter prune if plants become congested. Remove dead and crossing branches and reduce some branches by a third if the plant hasn’t been bushing out.

My two established bushes growing in a bed in the fruitcage give a steady supply for morning muesli and a delicious nibble during the day. But they also thrive in pots and their pretty, white bell shaped flowers in spring and fiery autumn colours make them very decorative.

You do need to use acidic soil – pH 4.5 - 5. If you’re not sure about your soil’s alkalinity use a simple test kit to find out, don’t just assume you know. The soil’s pH level determines the availability of nutrients to plants which need a different balance of nutrients according to their species. So even when specific nutrients are plentiful in the soil, acidity or alkalinity can lock it up denying a particular plant’s needs. This means acid-loving plants such as blueberries require low pH ground.

When buying, only choose a blueberry that’s been grown in a pot: they don’t take kindly to root disturbance, so are weaker if simply dug up at a nursery and plonked in a pot.

Use ericaceous compost in a container. The plants need some, but not too much nutrient, so avoid using any animal manure as it’s too strong, could scorch roots and kill a blueberry.

Since blueberri ses don’t quickly grow an extensive root system, you’ll need to start in a pot with a diameter of around 40cm and only transfer to a larger 50-60cm after 2 - 3 years. The plants simply won’t use the extra compost in a larger pot so the compost will sit wet and could damage the plant above.

After planting, use lots of water to let roots bed in and cover compost with mulch to conserve moisture. Blueberries are high on a blackbird’s list of preferred fruits, so protect the crop if you’d like some of the berries too.

Plant of the week

Common Knapweed, Centaurea nigra, is an end of summer stalwart growing in a wide range of grassy places. Its purple flower heads look good in rain or shine and are a top favourite with late summer butterflies like Peacocks and Red Admirals. The neat, dark seed heads are relished by goldfinches.