As container shrubs have limited access to any available moisture and nutrients, they generally need watering and feeding more often than those planted in open ground. They will also need to be periodically top-dressed or repotted.

Feeding

Container shrubs should be fed two or three times a year between early spring and mid-summer using a quick-release, balanced liquid fertilizer.

Watering

The canopy formed by the shrub leaves often stops rain from reaching the soil in the pot, and so you should check the container compost at least once or twice a week, even in rainy weather. When watering, soak the compost thoroughly until water starts to drain through the holes in the base of the container. Do bear in mind that windy weather will cause rapid moisture loss, and so the shrubs are likely to need additional watering during this time.

Re-Potting

Re-pot shrubs young shrubs every year or two in spring until they reach maturity. After this, you will only need to top-dress the plant every year; however, you will need to re-pot whenever the shrub starts to lack vigour or becomes too large for its present container.

1. Prepare a new container by placing crocks over the drainage holes of the pot and then covering them with compost.
2. Carefully lay the shrub on its side and, with one hand supporting the root ball and stem, knock it out of its pot by sharply tapping the base. You may need to slide a long-bladed knife between compost and pot to loosen the root ball.
3. Remove the top 5 cm (2 in) of compost and any moss or weeds, then gently tease out the roots, cutting back by up to two thirds any non-fibrous roots that are coarse or large. Position the shrub in the pot, spreading its roots out evenly.
4. Add the compost to the pot in stages, firming it gently, so that the fresh compost reaches the soil mark of the shrub. Leave about 2.5-5 cm (1-2 in) below the rim of the pot to allow for watering and top dressing.
5. Prune back any dead, damaged or straggly stems to produce healthy, vigorous growth, and to create a well-balanced framework of stems.

Top-Dressing

Top dress the shrub in the spring by removing the top 5-10 cm (2-4 in) of compost and replace with fresh compost enriched with slow-release fertilizer.

You will need to take care not to damage any surface rooting shrubs; instead of removing the top layer of soil, ease them out of their pot and remove the bottom layer of soil. Add a smaller layer of enriched compost into the bottom of the pot and replace the plant. This will now sit lower in the container, allowing room for a top-dressing.

After you have finished, prune back any dead, damaged or straggly stems to revitalise the shrub so that it will produce healthy, vigorous growth.