From University of Illinois Extension Garden packet
URBANA, Ill.—Choosing plants for a container can be intimidating, said a University of Illinois Extension horticulture educator.
“You may think you’re not creative enough or that you don’t know enough about plants,” said Jennifer Schultz Nelson. “But, with a few tips and tricks, you will be designing container gardens in no time. You need to start with the basics.”
First, choose a container that coordinates or complements the color of your deck. Whatever you choose, make sure there is a hole in the bottom for drainage. This sounds really basic, but it is easily overlooked when shopping for a pot.
“If you are going to place your pots in a sunny location, remember that unglazed, clay pots will dry out relatively quickly in the sun,” she noted. “You may wish to choose a glazed ceramic or even plastic pot for a very hot, sunny location. Also, it may be a good idea to choose a larger pot as a larger volume of soil will dry out more slowly than a smaller volume of soil.”
The disadvantage of larger pots is buying enough soil to fill them. It would cost a small fortune to fill some of the giant urns and pots available in stores. And because most annuals develop a fairly shallow root system, around six to eight inches deep, it’s really a waste to have soil two feet deep in a pot. Instead, Nelson suggests placing inverted plastic pots or a plastic bag filled with Styrofoam packing peanuts in the bottom of your pot to act as filler. The pot will be a lot lighter, and you won’t have to invest in soil that your plants never utilize.
“It’s tempting to use your regular garden soil for your container gardens, but don’t,” she cautioned. “Garden soil is much too heavy, does not drain well enough, and may harbor pests and disease. Instead, choose a quality mix labeled as ‘potting’ or ‘container’ mix.
“These types of mixes are formulated to be sterile, drain well, and are much lighter than the soil in your garden. Many mixes available now come with time-release fertilizer incorporated into the mix, as well as moisture-retaining polymers that slowly release water to your plants after watering.”
One of Nelson’s favorite tips in designing container gardens is that there are three types of plants in a container garden: the thriller, the filler, and the spiller.
“I wish I knew who originally coined these terms as I think they are a great guideline in choosing plants,” she said.
The thriller is the tallest plant in the bunch. It grabs your attention in how it stands above the other plants. The filler is a medium-sized plant that dominates the center area of the pot. The spiller cascades down the side of the pot, drawing attention downward.
“In my experience, container gardens look best when you have at least one of each of these plants in the mix. Also, odd numbers of plants tend to look best.” she said.
“But just because you have a thriller, filler, and spiller doesn’t mean they look good together. You still have to pay attention to color. This is where many people get frustrated. In my opinion, you will have the best results if you keep your color choices simple.”
The simplest method is to choose different shades of one color. Another choice could be a palette of warm colors, which includes red, orange, and yellow. Green, blue, and purple are the cool colors.
“At the same time you are choosing your plants with colors that work well together, keep the plants’ preferred needs in mind,” she said. “Choose sun-loving plants for sunny locations, shade lovers for shady spots. Do not mix shade-loving plants with sun-loving plants in the same pot, or one of the plants will be unhappy no matter where you place it.
“If you are trying to choose plants for several containers at once, it can quickly get confusing. Group plants for each container together in your cart and ask the cashier to bag or box them together. This increases the likelihood that you’ll remember how you wanted to use each of the plants once you get home.”
From the May 12-18, 2010 issue