June / 2001
At Home in the Garden

Large container gardening
by:  

The last spring garden chore for me is installing all my container gardens. As I look around I have quite a few containers to fill-nine in all and each of them is less than 16 inches in diameter. When the 90-degree days of summer hit I have to water them almost every day.
I also design and install container gardens for clients each year, and as I was reviewing some of my designs recently, I questioned why I chose such small containers for my home when I always choose the biggest possible containers for my clients. The truth is I hadn't given the same considerations for maintenance at home as I do for the commercial accounts. I design high-color, low-maintenance container gardens. So with lower maintenance being my new motivating factor, it is time to make a few changes at home.

Proportional Plants
Switching to fewer but larger containers can be expensive, but will not reduce the overall show of your container gardens; in fact, it can have the opposite effect and bring the show up a notch. What's different about gardening in containers 25 inches in diameter or larger is that you have to choose plants that will grow larger than you would choose for your smaller containers. This is a must in order to keep the display in proportion.
While there is no plant I am afraid to try, there are several that I seem to use over and over again. Jasmine, canna lilies, aspidistra, gardenia, philodendron, and hibiscus are a few. I like to incorporate tropical plants into my large container displays to balance the display, and also because of the look and feel they bring to the displays. The tropical plants in many cases use less water than the annuals, helping to reduce the overall maintenance. I like to use an assortment of annuals, surrounding the tropicals, for season-long color. I also like to add plants that will cascade out of the container, like sweet potato vine or tropical ivy.

Water & Fertilizer
Because water management is the biggest chore, I have adapted my soil mix for outdoor containers. It contains two parts light soilless potting media (like Premier Pro Mix) and one part worm casting or complete landscape mix. This mixture holds water for a longer period and has better nutrient-holding capacity. Above all, never use regular, native garden soil.
An adequately sized container is essential and it must have a drain hole in either the bottom or sides; if it doesn't, you need to make one. In all my plastic containers I even drill holes in the sides at the base of the container: sometimes the weight of large plastic containers can compress the bottom, cutting off drainage through a single bottom hole.
Regular fertilization is as important as the drain hole. The light, porous medias required for container gardens do not hold nutrients well, so it is important to fertilize every two weeks during the season. A soluble fertilizer like Monty's Joy Juice or Daniels Plant Food is easily mixed up in a watering can or siphoned through your hose for regular application.