The Art of Outdoor Container Growing

“Flowers are restful to look at. They have neither emotions nor conflicts.” — Sigmund Freud

With a porch, a deck, a balcony and a semi-covered patio, I’ve got a lot of good places for raising potted plants. I spent sometime this weekend going through some favorite gardening books, getting ideas and reviewing principles that will not only improve my growing but also the aesthetic of potted plants. Here are some of the things that attracted me. Let’s hope they expand your thinking on container growing in the outdoor landscape just as they did mine.

Container Garden Idea Book put together by the editors of Fine Gardening magazine was one of the more browseable gardening books to come out in 2011.

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It doesn’t really spend a lot of time discussing soil, drainage and moisture control, and what kind of pots to use for successful gardening. And that’s fine with me. I figure I know enough to grow climate-appropriate plants in containers. It’s the aesthetics that challenge me. I don’t have a good visual eye. Luckily, the Container Garden Idea Book helps me see how pots and plants come together for visual appeal.

In fact, the book seems to have never seen a pot it didn’t like and recommends a whole array of containers, from those salvaged at junk yards to big, expensive metal and glazed-ceramic planters. They’re all about using all kinds of different containers together, side-by-side — wood, metal, stone, clay; even wire baskets which can be lined with moss and filled with soil — to add contrast, as long as it goes with the garden’s theme, design-style, or color scheme (if you have one).

In my case, this will be a couple of old, grizzled wood boxes saved from a tear-down in which I’ll drill some drainage holes and reinforce with a handful of weathered screws. They’ll go on the porch’s rail with some annual flowers and trailing vines.

I have some large clay pots of various sizes that I want to front a really big pot holding a Japanese maple if I can find one that will overwinter in its container in zone four. Potted plants intended to overwinter in their containers should be at least a zone and maybe two lower (more cold tolerant) than if they were to be planted in the ground — see Overintering Potted Plants. You can help this situation by getting your pots off the ground, say on a couple short two-by-fours, to help air circulate beneath the pot.

Growing trees and shrubs in pots (PDF) is an art in itself.

You probably already know which pot-suitable plants, both annual and perennial, grow well in your area. The next step is then to consider the pots as part of the color scheme and choose plants accordingly. A big, showy, decorative pot should be planted with something upright that keeps the pot visible. No trailing vines or growth that will hide the container. On the other hand, if its just an old clay pot that’s familiar if not unique in the way it’s weathered, don’t be afraid to fill it with plants that trail and obscure its clay.

My place for a large pot is at the base of the stairs to the front porch on a patch of the concrete off to one side. There’ll be room for two or three smaller pots to front it. That’s where I’ll put seasonal plants designed to trail and provide color. Or maybe stuff a couple pots with tulip bulbs to put front and center as spring dawns. That’s the other thing about growing in pots: the soil in containers warms up more quickly in the spring than it does in the ground.

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The seasonal aspect of container planting is Sara Begg Townsend and Roanne Robbins’ Continuous Container Gardens. Townsend and Robbins embrace the idea of planting perennials, say a shrub or dwarf tree, in pots large enough to contain them — always give a potted plant more root room than you think it needs — while seasonally swapping out the understory (what grows beneath that focus plant).

As in the Idea Book, Townsend and Robbins suggest layering plants to give pottings contrasting heights and dimensions. They even suggest pairing plants that appreciate different soil and light conditions if those plants look good together. Townsend cites an example where they planted sun-and quick-draining-soil loving catnip beneath a miniature birch that likes partial shade and moist soil. They figured the catnip which “looked so good, so crisp, just the right colors and textures” wouldn’t do any better planted in their garden over the first summer so they stuck it where it would show off. They moved it out of the pot the next planting season.

Along the catnip line, Townsend and Robbins will plant seasonal salad greens around the base of their focus plant and harvest them when ready. Then some other plant, either purchased or raised in their garden, goes into the space.

Needless to say, these two women are transplanting fools even as they establish permanent plantings in large containers.

Both books, richly illustrated, demonstrate how containers make gardening almost anywhere possible. They also consider the pot as part of the landscape, part of the beauty of your planting. Sure, you think your garden dirt is beautiful. But it can be even more attractive inside a handsome planter.