Proven Winners’ Intensia phlox (rear right of planter) are an excellent container choice for their bold color, robust flower production and drought tolerance.
Whether you’re pressed for space or garnishing your landscape, adding containers to your garden expands your planting possibilities and adds a punch of color and foliage to your design palate.
Tucked among your perennials as a statement piece, flanking your entrance as a welcome, conveniently holding kitchen herbs on your back patio, or even providing a miniature vegetable patch on a city fire escape, containers are endlessly versatile.
With the plethora of planters available and a corresponding wealth of container-friendly plants, creating a show-stopping display has never been easier.
“Containers are so much fun,” says container gardening expert Chris Abel, whose Custom Container Gardening (717-314-3086) business creates designs for regional corporate and private clients. “They bring color and nature right up close so you can enjoy it while you’re on your patio or grilling burgers, instead of looking across your yard and seeing plants from a distance.”
Abel especially likes to use pollinators and plants that attract hummingbirds and butterflies in her containers.
“People like that up-close experience of nature,” she says.
Vessel varieties
When planning a container garden, having a style in mind helps narrow down the choices of containers. Formal gardens may call for classic urns, informal gardens are just as happy with whisky barrels, and more whimsical gardens can employ everything from bathtubs to wheelbarrows. The key requirements of a container are that it holds several gallons of soil and has enough drainage to keep plants from rotting. If your container doesn’t have good drainage, either drill more holes in the container, or line the container with gravel or pebbles, then set another pot with adequate drainage inside.
When choosing containers for your plants, bigger is definitely better.
“The larger the pot, the easier to care for,” says Abel. “A larger pot means less watering; the soil doesn’t dry out so quickly, and there’s more room for plants to grow.”
Abel suggests using at least a 22-inch-wide pot to make for a realistic watering routine.
Formal gardens may call for classic urns, informal gardens are just as happy with whisky barrels
“You don’t want to have to water three times a day,” she says.
Choosing the appropriate sites for the containers is also important.
“You don’t want to put a pot on a brick patio next to a brick house with full southern exposure,” she says. “That’s just asking for trouble.”
Even if you are choosing plants that require full sun, when planted in containers that heat up more quickly and intensely than garden soil, these plants will welcome some mid-day relief.
As for choice of material, she avoids metal pots that can cook the plant roots. Terra cotta pots are classic and attractive, but their porous nature means extra watering in the hot months. Glazed ceramics can be a good choice, but some need winter protection, either by covering them or moving them indoors. Abel is also impressed with the improvements made in plastic and fiberglass pots, which are easy to customize with extra drainage holes and paint choices.
“But my favorite is cast concrete, even though it’s pricey,” she says. “It’s not easily moved, so make sure you place it where you want it.”
In placing pots, Abel is also a strong advocate for pot “feet” that elevate the containers to allow for proper drainage and air circulation. Otherwise, water can pool in the bottom of the containers and rot the roots.
“I love them. I’m a collector,” she says, “but if people can’t find them, you could just use three bricks under each pot.”
Preparing pots
Once you’ve figured out where you want to place your containers, it’s time to fill them. Abel strongly advocates using a soil mix specifically designed for containers. Our region’s clay garden soil is too heavy. A lightweight porous mix helps facilitate water drainage.
A soil-less mix is most ideal for containers where weight is a consideration, such as window boxes, hanging baskets, and roof gardens. Soil-based mixes (packaged and sterilized, not from your garden) work better than soil-less mixes for large, heavy plants, especially permanent ones. They generally hold fertilizer longer than soil-less mixes and do not become too wet or too dry as easily.
When you’re ready to plant your containers, make sure you start off with slightly damp soils. If you can, soak the soils the day before. If you’re using terra cotta pots, it’s also a good idea to soak them before planting. To prevent soil from washing out the drainage holes, cover them with fine screening. Water your plants before and immediately after planting to remove air pockets and settle the soil around the plants.
Plant selection
Now for the fun part. When selecting plants for your containers, think about your site. What kind of light does the area receive? Will plants be exposed to wind? Will they be out in the rain?
This will help you with plant selection. When planning a container, be sure to group plants with similar cultural needs together.
Inspiration for both containers and plant selections can be found in garden centers, gardening magazines, public gardens, and even around your neighborhood.
“I love visiting local greenhouses to get ideas,” says Abel.
Just about any plant can be grown in a suitable-sized container, from small trees and shrubs to roses or climbers, as long as there’s ample space for them to develop roots.
To begin designing your display, whether it’s one pot or a cluster of containers, start by thinking about the size, shape, and texture of the plants.
You can go for one specimen planted en masse to make a bold color statement, like the fail-safe Wave petunias commonly planted in city hanging baskets. Or you can design each container to make a stunning, singular display of form and texture.
For beginners, the rule of thumb is to pick three different kinds of plants: a tall spiky variety, one that is bushy, and one that will drape down the sides of the container.
“Beginners tend to choose things like verbena, petunias, calibrachoa,” says Abel. “But there are so many other cool plants in the world to try. I’m a big foliage person, because you don’t have to rely on blooms.”
Abel particularly likes to use succulents in containers, as they weather the arid conditions better than most plants.
Plant breeder Dr. Kris Barry of Groff’s Plant Farm in Kirkwood (www.groffsplantfarm.com; 717-529-3001) is also a big fan of textured foliage in container plants, like the twining emerald colored muehlenbeckia “Wire Vine” to drape over the sides or the bold, tall pseuderanthemum “Black Varnish” with its high-gloss, deep maroon foliage. For shady sites, she says you can’t beat the nearly infinite varieties of coleus. Her favorite of the moment: the vibrant “Burgundy Wedding Train” variety.
Her top picks for new “fillers and spillers” of annual blooms: the pinkish foliage and peachy pink flowers of centradenia “Cascade;” the trailing yellow flowered mercardonia “Gold Dust;” the new phlox varieties “Intensia” and “Phloxy Lady;” and the uniquely hued mounding petunias “Black Velvet” and the yellow and black “Phantom.”
“I’m also really excited about the intense colors of the anagallis ‘Wildcat Blue’ and ‘Wildcat Mandarin,’” she says. “By themselves the plants aren’t that exciting, but trailing through a container, they’re stunning.”
If you’re planting containers for food consumption, Abel suggests a combination of kale or chard in the center for height and structure, herbs to mound and fill the container, and nasturtiums to spill over the side for color.
“Cooks love it,” she says. “I do containers mixed with herbs for Checkers restaurant and the chef comes out to trim them for dinners.”
Maintain
Containers are a closed environment, so it’s up to you to give them enough food and water to flourish.
“The most important thing I can say about watering is to water at the base of the plant,” says Abel. “Watering the foliage and flowers is just asking for trouble.”
Abel suggests watering the containers enough “so that the water drains through, then come back and water again.”
If you have problems with the containers drying out, you may want to group them together so their foliage can help shade the soil.
To feed your container plants, Abel says that “blue water” of commercial water-soluble plant foods is fine, but for superior performance, she has found that worm castings are best.
If you are growing vegetables in containers, Dr. Barry suggests using a fertilizer specifically designed for this application.
“Most fertilizers are high in nitrogen and don’t have enough potassium or calcium for fruiting vegetables like tomatoes,” she says. “Herbs and lettuces and other leafy vegetables will do just fine with nitrogen, but fruiting plants need potassium.”
Shifting seasons
The beauty of containers is their changeability. Once the plants have peaked, simply replace them with something new.
“In the spring I like to use forsythia and pansies for a beautiful burst of color, in the fall beautyberry bush, and for winter, greens and holly and winterberry,” says Abel.
With containers, you can celebrate the best of each season.
