Pot selection

Choose a container large enough to give your shrub's roots room to grow and weighty enough to balance the top-heavy growth. If you intend to leave the shrub outside all year round, make sure the container is fully frost-proof.

Wooden half-barrels are useful containers for larger shrubs, but ensure they are of good quality or they may fall apart prematurely.

Compost

Peat-based multipurpose composts are fine for container bedding plants, but are not usually suitable for shrubs. Loam-based composts are a better alternative as they retain nutrients.

Ericaceous plants, such as rhododendrons, need an ericaceous compost. This is usually peat-based, but is more acidic than ordinary peat-based multipurpose composts.

Drainage

Put 7.5cm (3in) layer of broken terracotta crocks at the bottom of the container before filling with compost. Chunks of broken-up polystyrene plant trays are a good alternative and also help to keep down the weight of pots.

Before you add your drainage layer, check that your container has good drainage holes. You may need to use a hand-drill to enlarge any existing holes or make new ones in plastic and wooden containers.

Good drainage prevents the roots suffering through the compost becoming waterlogged. Waterlogged containers are more at risk of frost damage in the winter as the expanding action of the frozen water in the compost puts the container under so much stress that it breaks.

Another tip for good drainage is to stand the container on terracotta pot feet or chunks of wood to raise it off the ground and allow the drainage holes to work unimpeded.
Watering

Containers need regular watering

Containers need regular watering, even after heavy rain, as many shrubs have large root systems that use a lot of water. In the open border, the roots often spread over a large area in their search for water, but in a container they depend on the water they're given.

Feeding

Feed regularly with liquid feed during the growing season. An easier solution is to put slow-release fertiliser into the compost. These products need to be replaced after a while as their nutrients become exhausted.

Acid-loving plants, including camellias and rhododendrons, need to be fed with an ericaceous fertiliser. This prevents the leaves turning yellow, or chlorotic, due to iron-deficiency.
General care

* Pruning - prune your shrubs regularly to keep them within bounds. Make sure that you have checked the individual shrub's reqPrune regularly to maintain their shapeuirements.
* Deadheading - remove bloomsDeadheading blooms as they fade to avoid the plant wasting energy by setting seed. You may get a second flush of flowers.

Repotting

If your shrub appears to lack vigour or is too large for its pot, repot in a larger container. Remove from the old pot, teasing out the roots gently if they are congested. Prune back the non-fibrous roots by about a quarter and replant in a slightly bigger container.

Top-dressing

Top dress annually if your shrub doesn't need repotting. Remove the top 5cm to 10cm (2in to 4in) of compost in spring, taking care not to damage the roots. Replace with fresh compost, water well and mulch with bark or grit to retain water and deter mosses from growing.

Winter protection
Insulating containers

Container plants are more at risk of freezing than plants growing in the open border. Plants with fleshy roots, such as camellias and hollies, are particularly vulnerable to damage. Wrap your containers with an insulating layer of hessian or bubble-wrap for the winter to help avoid these problems. Move vulnerable plants into a sheltered place, such as a porch or cold greenhouse, to get them through the worst of the winter weather.