As all plants, shrubs can be grown in containers. The main period for planting shrubs in containers is late summer to autumn. When you are planting a new bought shrub or transplanting one that you already have, you should choose the new container with 5 cm larger in depth and diameter than the previous one. If you are using an old container, scrub its inside surface thoroughly before filing to avoid propagation of any possible diseases that it may contain from the previous plant.
Large shrubs require big containers, so consider placing these heavy containers in their final position before planting them because they will be too heavy to be moved once filled with soil and plants. Stand the container on bricks or blocks to allow free drainage. Also place broken crocks over the drainage holes and then add a 2.5 cm layer of drainage material, like coarse gravel, to obtain a good drainage of your container.
Over your drainage material you can now add the potting compost. Use loam-based compost, which is rich in nutrients, rather than peat-based compost, which contains only limited, added nutrients and dries out more rapidly. If you are using peat-based compost to plant you shrubs then consider feeding them regularly. For planting rhododendrons and lime-haters use ericaceous compost. Also use it for obtaining blue flowers on hydrangeas.
After placing the plant in the pot, spread its roots out evenly and work compost round them. Make sure that the soil mark is level with the compost surface. Also ensure that the compost is at least 4 cm below the rim of the pot to allow enough room for watering and mulching. Top-dress the compost with a covering or grit or bark chippings to avoid the soil from forming a crust. This mulch also looks decorative.