Container Garden: Planting

Last week, our column covered the basics of container planting. This week, we look at design and plant selection. When a few basic principles are applied, even first-time gardeners can create and maintain attention-grabbing containers.

Plant selection depends on location, light and temperature. A container could contain many different types of plants, including ornamentals, succulents, herbs, vegetables, and even small shrubs and trees. Make sure you choose plants with similar growing requirements for your container. How you arrange your choices depends on container location. If you will be looking at the pot from all sides, the classic approach is to place tall plants in the center and then surround them with shorter mounding plants and finally finishing off with trailing plants along the edges. If it will be viewed from the front, locate the tall plants at the back and work forward with shorter plants and then trailing types. If you are not sure of your design, set the plants on top of the soil to visualize the arrangement before you start to plant. You can adjust as needed. 

In choosing plants, a good rule of thumb is to pick a “thriller, filler, and spiller.” The thriller should be eye catching, colorful and the focal point of your container. Stroll through our local nurseries to find something that attracts you. It might be a tall plant, or one with large or showy flower or interesting foliage. It should draw the most attention of all the plants in a container.

The fillers and spillers need to have the same growing requirements as the main plant, but can be different colors and shapes. A spiller is a plant that spills over the edge. The foliage drapes over the sides of the container and balances out the height of the thriller. Many spillers have flowers, but they tend to be simpler or smaller than the thriller. Spillers are typically planted along the front and sides of the container.

A filler fills in the space between the thriller and spiller. It usually has more dainty flowers than the thriller or spiller and is shorter than the thriller, and doesn’t trail over the sides of the container. The filler unifies the container garden and supports the other two elements. Examples of fillers and spillers are baby’s tears, blue star creeper, creeping thyme, bacopa, and Irish moss.

These three elements help organize most containers. However, different locations can require different combinations of the elements. A hanging basket might look good with several spillers, and may not need a thriller or a filler. A tree or shrub-like thriller in a large container may benefit from a spiller, but no filler. Another good rule is to use odd numbers of plants equally spaced for fillers and spillers.

Planting a container garden is similar to planting a regular garden or flowerbed. Fill the container with your selected soil, leaving an inch or so between the top of the media and the top of the container to prevent soil from washing out when watering. There is no need to place pebbles in the bottom of a container, just mesh or larger rocks to cover the drainage holes. Do not pack the soil, allowing roots to get air. Loosen the roots gently before putting plants into the container. Make sure the root ball is covered with about ½ inch of soil. Once all the plants are in the container, water until you see the water draining out the bottom of the container. This encourages deeper root growth and helps to flush out any buildup of salts. To prevent leaking or staining the surface under the container, you may want to put a saucer underneath the container. Be sure to dump out the water as soon as possible, as standing water in the saucer can lead to disease and harbor pesky mosquito larva.

Edible container gardening is a recent trend using vegetables or dwarf fruit trees to make lovely and edible container gardens. Tomatoes, peppers, carrots, lettuce, and beans are a few of the vegetables commonly found in container gardens. Dwarf fruit trees, such as peach, apple and orange can also be planted. Since food production is the goal, larger containers are generally required. Many popular edible plants and trees need at least 5-gallon or larger containers. Five-gallon buckets or reusable soil bags may not be pretty, but they are cheap and support good production. Most vegetables and trees need lots of sun and water. Some need a trellis or support system. When using a support system, use a heavy or weighted container to prevent tipping over. Edible containers are not just limited to vegetables or trees—herbs and ornamentals can be grown in the same containers. Flowering plants can help bring in beneficial insects, pollinators, and add an attractive splash of color.

Now, here’s the information no one talks about! Outdoor container gardens with annual plants must be replanted every spring. Even perennials plants may not be winter hardy in a container. Potted shrubs or trees need to be replanted every 3 to 5 years to prevent the tree or shrub from becoming root bound. Repotting involves removing the plant from its container (no easy task if the plant or container is large!), pruning its roots, as well as the branches. Repotting prevents shrubs and trees from becoming too large for their potted environments, freshens up the soil, and prevents roots from growing around the inside of the container and even out the drainage holes.

Container gardening has an unsuspected benefit. In our era of sustainable gardening practices, including plant selection and lawn removal, containers are one way to fill the space left from a removed lawn. By choosing the right plants for your container and locating the containers in an attractive design, you are truly practicing “Gardening Central Valley Style.”

Pick your location, container and plants. Experiment with color, form, texture, size and shape. Let the fun begin!

The Master Gardeners will be live to answer your questions on Saturday, Jan. 21, from 8 to 11 a.m. at Visalia Farmer’s Market in the southwest parking lot of Sequoia Mall in Visalia; from 10 a.m. to 1 p.m. at their rose pruning workshop at the Ralph Moore Garden in Visalia; and at their 11 a.m. composting class at the Tulare Public Library in Tulare. You can also contact them at 559-684-3325, or visit their web site at ucanr.edu/sites/UC_Master_Gardeners.

This column is not a news article but the opinion and advice of the writer and does not reflect the views of The Sun-Gazette newspaper.

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