Using shrubs in container gardens provides many options to home gardeners, and landscape contractors as well. Sometimes container gardens are the only way to bring plant life to a patio, deck, porch or other area where there is no ground available to grow plants. I have over 150 container gardens of all shapes and sizes in my own landsape - ranging from 3 to 48 inches in diameter. I grow almost every type of plant in containers: shrubs, small trees, flowers, herbs and vegetables.
But this article is about planting shrubs in containers, so I'll stick to topic.
(Scroll down for step-by-step instructions)
There are many types of shrubs that can be grown in containers, and they have many types of uses. A row of tall growing shrubs in containers can create a boundary or provide a privacy screen. Shrub in containers can be useful on either side of a front door, sidewalk entrance or at the end of a driveway to accentuate these entryways. Container shrubs can also be useful in garden beds to provide texture, color and dimension. How you use them is entirely up to you.
For a shrub, growing in a container is much different than in the ground. Containers can provide excellent drainage, but this might mean they'll require closer attention to watering, especially during summer. Because their roots are more confined in a container, shrubs often stay smaller in a pot than they would in the ground. Another thing you'll want to consider when selecting shrub varieties to grow in container is that their roots will be exposed to air temperatures, which are often much colder during the winter months than soil temperatures.The general rule of thumb for container-plant survival through the winter is that the plant should be hardy to two zones colder than your USDA Hardiness Zone.
Selecting A Container
The first thing you'll want to do is select a container that fits the setting it will be placed in, and that compliments the beauty of the shrub.
Size matters. You want to match the pot size to the size of the srhub. I would recommend choosing a pot that is at least 4 to 8 inches wider than the nursery container the shrub was growing in. This will allow space for new roots to grow. Too, keep in mind that you'll want to match the size of the container to the size of the space.
Color and style matters. Pick a color of pot that goes well with the colors of the structure and/or the other plants in the area. Pick a style of pot that matches the style of your home or space. For example, if you live in a 1930's cottage bungalow, you don't to use ultra-modern pots.
Drainage is all important. Make sure the pots you select have drain holes or are constructed of a material that can be drilled through to make drain holes. Most clay and concrete pots provide excellent drainage and also allow air movement through the pot. That being said, clay pots are porous so they tend to dry out more rapidly than plastic and glazed ceramic pots.
Choosing The Growing Medium
When planting most types of shrubs in containers I use a a 50/50 mixture of a premium potting mix and standard potting soil. The potting mix helps hold moisture more evenly throughought the pot while the potting soil will add some weight to the mixture, which can help reduce water needs during the hotter and drier months of summer. What you don't want to use is native dirt dug out of your yard, which will most often lead to death of the shrub due to lack of aeration and poor drainage. Also, do not use straight compost, such as composted cow manure or mushroom compost, which are typically sold in bags. You can add a double handful or two of organic compost to the mix.
Choose plants that are known to perform well in pots, and one's that like the environment where the container will be placed.
Scroll below to see a listing of shrubs I am growing in containers
How much sun? It's important to know how much and when the sun the area will receive. If sites that provide shade or morning sun with afternoon shade, you can use shade-loving shrubs. If the sun shines for 8 or more hours a day you can use sun-loving shrubs. When combining a variety of plants in one container or grouping several pots in the same location, select plants that have similar growing requirements. Obviously, sun-loving and shade-loving plants are not very compatible unless the sun-lovers serve as an umbrella for the shade-lovers.
How much wind? If the site receives a lot of wind, consider using lower growing shrubs as taller ones might blow over, or use low-prifile, wider pots that will not blow over as easy. Too, you can place bricks, gravel, or other heavy objects in the bottom of pots for extra stability in wind.
Foliage and flower color. Shrubs come in an endless array of foliage and flower colors. You'll want to choose colors that match nicely with the color of structures and other plants in the area. Cool colors, such as blues, pinks and white shades are restful and soothing while warm colors, such as red, orange and yellow express action.
A color wheel is a diagramatic way of showing relationships between colors. Colors on the right side of the wheel are warm. Colors on the left side are cool. Colors adjacent to (beside) one another are analogous (similar). Opposite colors are complementary.
Habit of growth. Trailing or cascading shrubs, such as Purple Pixie Loropetalum, are good for use to cascade over the edges of containers or pots. Upright and taller shrubs, such as Sky Pencil Holly or Degroots Spire Arborviate, make good center pieces.
Step-by-Step Planting Instructions
1 - First you'll want to remove your shrub from the nursery container it was growing in. If the plant is rootbound and stuck in the pot you can cut away the pot using hand pruners.
2 - Then use your fingers or a claw-type tool to loosen some of the feeder roots around the surface of the root ball.
3 - Next, measure the height of the root ball of the shrub you are planting. Then fill the container with your 50/50 mixture of premium potting mix and standard potting soil to a height that will allow the top edge of the rootball to be about 1 inch below the top rim of the container you are planting in. Tamp the soil lightly and add more soil mixture if necessary.
4 - Now, set the shrub in the container and make sure the top edge of the root ball is 1 inch below the top rim of the container. Add more soil mixture if necessary to achieve the proper planting height. Then backfill around the root ball with your soil mixture, tamping lightly as you go until you have reached the top edge of the root ball.
NOTE: You can add an inch or two layer of gravel to the bottom of the pot to maybe help drainage, though I'm not sure how much a difference it'll make. Might be helpful if you were using a soil mix that was too heavy?
5 - Now you can apply a slow-release flower food or a water-soluble fertilizer at recommended rates on the product label.
6 - (Optional) To conserve moisture you can add a 1-inch layer of shredded wood mulch to the soil surface.
7 - Water deeply and your done!