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Fertilizing Containerized Woody Ornamentals

The use of containerized woody ornamentals, as shown in Figure 1, for patios and specialized areas has become an important feature in residential landscape design.

Woody ornamental in container

Figure 1 - Woody ornamental in container

To ensure vigorous, healthy plants in these containers, a growing medium composed primarily of organic materials (pine bark, peat moss, etc.) mixed with coarse builder sand or perlite to ensure adequate drainage is recommended.

Plants growing in these media require frequent irrigation and additions of nutrients. Before potting, the medium should be amended with 2 oz. of dolomitic limestone per cu. ft. This will raise the pH to about 4.5, a level conducive to vigorous growth of the plants in the organic medium, but lower than is recommended for growing plants in mineral soils.

Plants should be fertilized every two weeks in the irrigation water with a complete fertilizer with an approximate formulation ratio of 2:1:2. While the exact ratio is not critical, higher levels of phosphorus relative to nitrogen and potassium may reduce plant growth and vigor. Manufacturer's directions for application should be followed.

Fertilizer products that release nutrients over a number of months are also desirable and reduce labor associated with frequent applications.

Two types are currently available;

  1. Nutrients are contained inside a resin bead
  2. Nutrients are coated with sulfur.

Both will supply nutrients at satisfactory levels throughout the growing season.

The 2:1:2 ratio mentioned above should also be considered when purchasing these fertilizers. One example would be Osmocote 18-6-12.

Directions on the container should be followed and will vary depending upon the container size.