How to Plant in Pots
Container gardens are a movable feast for the senses. Here's how to assemble and care for knockout combinations
Clockwise from left: Container garden essentials include a pot with a flared mouth, potting soil, a trowel, slow-release fertilizer beads, a mix of plants, feet to elevate containers and keep from trapping moisture on wooden decks, pruners to tidy up plants, pottery shards to place over drainage holes, and gardening gloves.
Planting in containers allows you to garden where there's no ground to till, brightening up the patios, porches, decks, and stoops where we linger on long summer days. Containers also let you skip the major digging and weed-pulling of backyard gardening and fast-forward to the fun: designing, planting, and enjoying. You get just enough dirt under your fingernails to feel like you've accomplished something. Pairing up pots and plants in pleasing compositions, you can even work in perennials, grasses, and dwarf evergreen shrubs to provide year-round interest. Best of all, container gardens are close-up delights. They invite you to slow down, notice the details, and savor the scents. Here's how to pot up some gems.
1. Pick a Pot
Unless you're set on specific plants, it's best to pick the pot before you decide what's going in it. Look for ones in a style that suits your home. Classical urns look great on stone patios or flanking the front entry of a formal house, while clean-lined geometric shapes complement modern settings. Muted neutral colors emphasize the plants, while vivid ones draw more attention to the pots themselves. If you're going for a grouping, an odd number of pots generally looks better than an even-numbered collection. Aesthetics aside, there are also practical concerns when picking pots. For a mixture of plants, look for containers at least 12 inches wide. Annuals usually need at least 8 inches of soil depth, while grasses and shrubs may need two or three times that amount. The ideal container has straight sides or ones that flare out at the top for easy access. If you'll be placing pots on a deck or a rooftop, look for lightweight materials, such as metal or composite. These and some glazed ceramic pots also have the advantage of being nonporous, so they keep soil moister. Porous unglazed terra-cotta gets a wonderful patina over time but allows soil to dry out more quickly.
Any pot needs drainage holes so roots don't get waterlogged; these should be covered with pottery shards, stones, or a small piece of screening to keep soil from migrating out. If containers sit on a wooden deck, consider using pot feet or a plant stand to elevate them so that the decking doesn't stay wet, which will lead to rot.
Mix up Some Ornamental Edibles
This miniature kitchen garden, for full sun, provides culinary herbs and fresh berries all season: (A) tall bay (Laurus nobilis), (B) upright rosemary (Rosmarinus officinalis 'Roman Beauty'), (C) spearmint (Mentha spicata 'Kentucky Colonel'), (D) lemon thyme (Thymus citriodorus), (E) golden-leaved alpine strawberry (Fragaria vesca 'Golden Alexandria').
2. Assemble the Plants
Think beyond one-note plantings of marigolds or impatiens. For a long-lasting display, combine showy annuals with ornamental grasses, shrubs that change leaf color in the fall, or dwarf evergreens. Go for a mix of colors, textures, and foliage types. A tall grass, a delicate vine, and a plant with large, interesting leaves make a good combination. "A vertical element is important to give the planting height," says Gabrielle Whiton, a container-plant specialist at Bainbridge Gardens, a nursery on Washington's Bainbridge Island. She often starts with a dwarf conifer, then selects lower-growing and trailing plants to go around its base. One of those might be a flowering perennial or annual in a 4-inch container. She places this, pot and all, into the soil at the front of a large container. Once the blossoms fade, she can pull out the small pot and put in a new one with a plant just coming into bloom. She also likes to echo the pot color in her plantings.
To balance form and proportion in a pot, Ellen Zachos, owner of Acme Plant Stuff in New York City, which creates and maintains container gardens, relies on her own catchy recipe of "thrillers, fillers, and spillers." Thrillers are tall plants that go in the center or back, fillers are medium-size plants that fill out the middle, and spillers gracefully trail or cascade over the edge to soften the pot's hard edges."Resist the urge to crowd in too many different things," says Ellen Zachos, who likes to stick to three to five types, tops. "A lot of plants are fine, but a lot of different kinds of plants starts to look messy."
Unless you need a deck decoration for a party next weekend, select plants that are relatively small and let them fill out. Avoid buying ones whose roots stuff the nursery container. Dense root balls shed water, so these plants may become parched once you repot them, even if you water often. Pair up plants that are suited to the same exposure, whether sun, part sun, or shade, and that have similar water requirements.
3. Deal With the Dirt
Since ordinary garden soil is too heavy and can introduce disease, be sure to use a bagged planting mix or a homemade equivalent. Products labeled "potting soil" contain sterilized soil and other ingredients, while "soilless mixes" consist mostly of peat moss or peat substitutes, compost, and perlite or vermiculite to keep it loose. Soilless mixes weigh less but dry out faster, but some plants, such as succulents, prefer them. For a homemade batch, mix five parts compost with one part builder's sand, one part vermiculite or perlite, and one-quarter part dry organic fertilizer. Whichever medium you use, check to see if it contains slow-release fertilizer; if not, consider mixing in some granules at planting time.
Take the Container Color into Account
Play up pot colors with plantings. In this full sun mix, blue and yellow-green foliage and pink flowers enhance the planter's teal-rimmed golden yellow, including: (F) dwarf cypress (Chamaecyparis pisifera 'True Blue'), (G) blue oat grass (Helictotrichon sempervirens), (H) 'Glacier Blue' euphorbia, (I) pink miniature petunias, and (J) creeping thyme (Thymus vulgaris 'Silver Posie').
4. Planting and Maintenance
If you are growing shallow-rooted specimens in tall pots, you might want to fill in the bottom half with lightweight materials such as broken terra-cotta pot shards or Styrofoam packing peanuts. This promotes drainage and prevents waterlogged soil. Start planting in the center or with the largest specimen and work outward, scooping and filling as needed so that the plants wind up with soil at the same level that they had in the original containers—1 to 2 inches below the lip of the pot. Give plants a thorough drink, using a watering can or a soft-spray nozzle on a hose. Check the level of the soil again and add more if necessary. Keep watering often—whenever the soil is dry 2 to 3 inches below the surface—and fertilize regularly (if you haven't used slow-release beads), following package directions. Clip off spent blossoms or branches that grow too long. With just this minimal maintenance, your container gardens will flourish all summer long, and—depending on what you've planted—even beyond.
Where to Find It
Gabrielle Whiton, Bainbridge Gardens
Ellen Zachos, Acme Plant Stuff
Containers and plants:
Bainbridge Gardens; Bainbridge Island, WA
Atlas #370 Nitrile Soft Flex Gloves
Atlas Glove Consumer Products
Forged flower shears
Lee Valley Tools
For further reading:
Down & Dirty: 43 Fun & Funky First Time Projects & Activities to Get You Gardening by Ellen Zachos
North Adams, MA