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Growing Rhododendrons in Containers

Rhododendrons can be grown in containers with success.  Having your plants in containers can give you many options for your landscaping.  It allows you to give “feet” to you plants to find the perfect location or to give them additional shelter during the winter months.  Container growing is also a great option when ground is not available such as on a deck or balcony. 
When you are growing a rhododendron, or any other plant in a container, it is very important to consider the resources that your plant will need during its life.  The larger the plant will grow, the more nutrition and water it will need to prosper.  When considering rhododendrons for containers, selecting plants that will not grow as large will allow you to plant into a container that you can move around without needing a forklift and also allow the plant to reach it’s potential.  Selecting a rhododendron that will grow to four feet tall and wide will allow the use of a fifteen-gallon container that is still mobile.  For each foot less in height, you can subtract five gallons in container size.  These sizes are approximate recommendations.
The soil medium that you choose is very important.  Rhododendrons need to have well drained soil.  A potting mix with sand works great.  Do not use the soil blends that hold moisture.  Make sure that the top of the root ball is at the soil level.  Spreading mulch or fine bark at the top of the container will give your plant a layer of insulation to help with water evaporation.
When you plant your rhododendron in a container rather than the ground, it will miss all the resources that the ground provides.  You will need to water your plant more often.  Leaving a saucer under the container is not recommended.  Remember, your plant wants to have moist roots, not wet roots.  You will also need to feed your plant on a regular basis.  Use a slow release fertilizer designed for rhododendrons.  We do sell a very good fertilizer on our web site, but you can also find it at your local nursery or big box store.  You will need to apply this fertilizer at least twice a year, following the directions on the package.
When your rhododendrons are in the ground, the earth acts as an insulator for the root system.  In a container, these roots are exposed to the large fluctuations of the daily temperatures.  Keep this in mind when placing your plants in direct sunlight.  You will want to avoid the container from getting too hot.  Also, in the winter, roots are exposed to the cold air temperatures.  If you get subzero temperatures, consider moving your plants out of areas of exposure.  A great place is by the house.  Rhododendrons do not like the temperatures and humidity of the house, so keeping them outside is the best idea. 
Container growing is a great way to add color to any place outside!