5 Steps to Perfect Planters

How to Design Sensational Container Plantings

One of the two pots on my front porch last summer: million bells (Calibrachoa 'Apricot'), sweet potato vine (Ipomoea 'Blackie'), Diascia 'Flying Colors Apricot', Purple Fountain Grass (Pennisetum setaceum 'Rubrum'). The vine in the background is 'Heavenly Blue' morning glory.

"Why don't my pots ever look like that?" If you find yourself asking this question, I'm here to tell you that they CAN, and how to do it. Here are five tips for success, gleaned from my own experience and that of the experts in our retail store here in Burlington, Vt.

There are so many incredible pots these days in all shapes, sizes, styles and colors, that trying to choose one can be a bit overwhelming. Think first about where the pot will be placed and make sure you get the size right. Containers usually look best when there's about twice as much plant as pot.

Remember that good-looking plants have good-looking root systems. Make sure the pot you use is large enough to contain the entire root mass (3 months after you plant!). A good size pot also means more room for soil, which means more room for moisture and less need for frequent watering.

All pots should have drainage holes at the bottom or sides so excess water can drain out and roots won't get waterlogged. Self-watering planters have a built-in water reservoir to ensure roots have access to a consistent supply of moisture.

The style of pot should also suit your home, and if you already have a color scheme in mind for your plants, make sure the pot will complement these colors.

As a general rule, planters look best when you select one plant that has a vertical habit (such as phormium, canna, calla, pennisetum, or upright fuchsia [Fuchsia triphylla 'Gartenmeister Bonstedt']), two or more with a horizontal, weaving habit (such as heliotrope, osteospermum, petunia, coleus or impatiens) and one or more with a cascading habit (such as nemesia, helichrysum, ipomoea or calibrachoa).

You can choose two different kinds of plants to play the same role (two cascading plants, for instance). When you are at the garden center, stand the plants next to each other and try to imagine how they will interact later in the summer when they're four to 10 times larger.

Container plantings that combine shades of a single color, such as purple or yellow, can be very effective. Another combination that's been very popular in our Vermont store is blue, pink and gray. But bright, sharply contrasting colors—such as purple and orange or yellow and blue—are also increasingly popular. (Click here to see some of our favorite combinations.)

Foliage color provides another opportunity to create interesting color combinations. Consider experimenting with:
Lime green: Ipomoea batatas 'Marguerita' or Helichrysum 'Limelight'
Gray: Helichrysum or Centaurea 'Colchester white'
Variegated: vinca or plectranthus
Burgundy: Ipomoea batatas 'Blackie', perilla or tradescantia
Highly colored: coleus, strobilanthes (Persian shield) or canna lilies

You can also combine different foliage textures: the shiny leaves of cannas, phormium and New Guinea impatiens or the felted leaves of Helichrysum petiolare, heliotrope or a dark-leaved coleus, such as 'Felix.' And don't forget about leaf shape. You can create lots of visual interest by contrasting the broad leaves of canna lilies or strobilanthes with the sword-like leaves of phormium or the finely textured foliage of verbena or calibrachoa (million bells).

Your container-grown plants want a mix that is loose and well-aerated; moisture retentive yet well drained; easy for roots to penetrate. Our Container Mix has been specially formulated to address these needs. It is comprised of ground sphagnum peat, vermiculite and sifted compost. If you make your own blend, just use a combination of these same ingredients. Avoid using garden soil because it is much too dense for container growing.

Use fresh soil every year to ensure good aeration and avoid the accumulation of fertilizer salts that can inhibit healthy root growth. Fresh soil will also prevent disease and pest problems that might otherwise linger from a prior year. The price of fresh soil is a fraction of what you'll invest in plants. It's well worth the $5-10 to ensure a long season of healthy growth and abundant blooms.

The single most effective thing I've done to improve the appearance of my container-grown plants is to fertilize them three to four times a week. For years I just never made the connection that my plants were growing in a nutrient-free soil mix and I was expecting them to survive on a diet of nothing but air and water. No wonder they looked pathetic after I'd starved them for two or three months!

If you use an organically-based fertilizer such as Plant Health Care for Flowers, it's pretty difficult to over-fertilize your container-grown plants. I add two heaping tablespoons to each of my 3-gallon blue watering cans about every other day. What an incredible difference it's made.

The other thing I've done that's made a huge difference has been to water frequently so my plants never dry out. I learned a couple years ago that it's the growing tips of a plant's root system that absorb most of the nutrients and water. If these delicate root hairs dry out, they die, and the plant must generate new ones. A plant will concentrate on doing that before it will put energy into foliage or flowers. These wet/dry cycles also stress plants and may cause them to go to seed more quickly than they would if they received a consistent supply of moisture. Self-watering planters make it easy to ensure there's always a supply of water on reserve.

It takes me about 15 minutes every morning to water (and fertilize!) all the plants on my front and back deck. I have to plan ahead to make sure I have time to do it before heading off to work. But that's 15 minutes every day that I get to listen to the birds as the watering cans fill, notice how things are growing, and appreciate the living art that surrounds my home.

Kathy LaLiberte has worked for Gardener's Supply since it began more than 25 years ago. She lives and gardens in Richmond, Vt. Click here to read more of her Innovative Gardener essays.