Pick a high quality container based upon size of arrangement wanted, location of arrangement, and whether it is likely to be moved.
You can’t build a beautiful container arrangement with an ugly pot. Worse yet would be building a beautiful container arrangement with a pot that breaks the first time someone bumps it or there’s a frost. Then, there are those cheap poly-resin or plastic pots that fade at the first hint of sunlight. In short, you get what you pay for.
At Urban Earth, we carry high quality planters made by Campania and Fiore. Whereas some concrete planters decay and crumble in just a couple of years, the best concrete is more durable, properly cured and sealed. Similarly, Campania’s ceramic pots are fired longer and at higher temperatures to create a clay pot that is much more frost resistant than less expensive glazed pottery.
Finally, bigger is generally better. Most people get pots that are too small for the context. The bigger the container the less vulnerable the arrangement will be to temperature fluctuations and drought.
No matter what kind of container you get, make sure there is at least one drain hole in the bottom, unless you’re creating a water garden or a bog garden.
Choose a good potting mix.
Container gardens never drain as well as in-ground gardens. Therefore, potting mix has to be much lighter and drain better than a garden mix. Otherwise, your plants will quickly succumb to root rot.
At Urban Earth, we carry top shelf organic potting mixes by Fox Farms. Cheaper potting mixes use synthetic fertilizers and cheaper fillers, making for plants with weaker stems and more fungal problems.
Use Soil Moist for hanging basket arrangements or those subject to potentially inadequate watering.
Hanging baskets loose moisture REALLY fast! Soil Moist is a water absorbing polymer that, when used correctly, holds in moisture better without making the mix soggy. It is similarly helpful in arrangements likely to receive inadequate attention, places like businesses or weekend homes.
Use a Drain-It disk.
Nearly every plant will need really good drainage to avoid root rot. Having a drainage hole or even multiple holes in the bottom of the pot will not guarantee good drainage. Gravity and time will conspire together to clog those holes. Therefore, good gardeners, in the old days, put gravel, broken terra cotta, or Styrofoam peanuts in the bottom of the pots. But, even then, that only delayed the inevitable compaction. So, the next step was to wrap the material in landscape cloth to keep the potting mix from descending into the reservoir. But then, some genius invented the Drain-It Disk and the world was a better place.
Choose the right mix of plants.
First, if the arrangement is going to be indoors, year round, it needs to be able to handle the stress of an indoor environment. We think of climate control, with year-round constant temperatures as being the ideal, but not all plants can handle it. Some plants need a period of vernalization or dormancy, which generally only occurs when temperatures drop below 50 degrees for a sustained period of time, each year. Moreover, the air in homes is much dryer than the air outside, in many parts of the country, not able to provide the humidity needed by some plants. Finally, in even the brightest spots in your home, there is usually less light than you could find anywhere outside. So, make sure the plants you use are plants with a solid track record of performing well indoors, plants like strawberry begonia, zz plant, English ivy, and philodendron, just to name a few.
Second, if the arrangement is outside, consider the amount of sunlight the plants will be getting. As is true with all garden designing, you need to know the terms for describing light conditions, “full sun,” “part sun,” “part shade,” “shade,” “morning sun,” and “afternoon sun.” Full sun means at least six hours of direct sunlight daily, part sun means 3-6 hours of direct sun daily, part shade also means 3-6 hours of direct sun daily but that the plants will be sheltered from western exposure (afternoon sun), preferring eastern exposure (morning sun), and full shade is less than 3 hours of direct sunlight daily. Only choose plants that are right for your light conditions.
Third, choose a combination of plants rather than just one or two plants and choose a nice combination of thrillers, fillers, and spillers.
The thriller is the tallest plant, the focal point of the arrangement. It can be a small tree like a coral bark maple, a flowering plant like Cordyline fruticose, or, if the arrangement is small, something like shrimp plant or Angelonia. Where you place the thriller in the arrangement, whether centered or off-center, is determined by the perspective of the arrangement’s intended audience. If the arrangement will be viewed from all sides, it is often in the center. Otherwise, it is off-center and in the back of the arrangement.
The filler is usually shorter and wider than the thriller but more upright than the filler. Its color and texture should simultaneously complement and contrast with the thriller. The filler should never try to compete with the thriller, its primary purpose being to provide visual support for the thriller. A few of my favorite fillers include hens and chicks, sweet flag, Firewitch dianthus, route 66 coreopsis, chocolate chip ajuga, or even mondo grass. But, it should be shorter than the thriller and taller than the spiller.
Finally, the spiller is like the scarf or the tie that completes the outfit. Great spillers include variegated English ivy, burgundy glow ajuga, creeping phlox, portulaca, wave petunias, and lemon ball sedum.
Consider the time-frame.
In magazines, arrangements are filled with plants, a solid mass. But, usually, in real life, arrangements start off with some blank space between plants, to allow the plants room to grow to their full size. If you place too many plants in a pot, you’ll be pulling some out in a few weeks as they grow to maturity and the arrangement becomes too crowded. So, it’s not good to overplant.
On the other hand, if the arrangement is for a special event, and you are determined to have immediate gratification with a full arrangement NOW, fill it up! Just know that, if you do, you’ll need to revisit the arrangement every few weeks, eventually repurposing or throwing away some of the plants.
Incorporate non-plant elements (sometimes).
Consider creative touches like lattice-work for a climbing thriller (think clematis or Carolina jessamine), miniature garden figures or small statues, and stones or gravel. But don’t go overboard and if you have a lot of container arrangements, don’t use non-plant elements in every one.
Promote good drainage by raising the pot off of the ground.
Even if you have chosen a pot with a drainage hole and you have sprung for a drain-it disk, if there is no space between the bottom of the pot and the ground beneath it, it won’t drain. Create space between the bottom of the pot and the ground with pot feet, pot dollies, plant stands, or even coins. You can, literally, accomplish this part of the arrangement for a few pennies!
Use plastic saucers or deck savers to catch excess water.
The thing about arrangements with good drainage is that they, well, drain. And, if the surface beneath your container isn’t something you want to get wet, you need to put something down there to catch the water, or, in the case of a deck, at least keep it from sitting and pooling in one place and rotting the wood.
Fertilize and water the arrangement appropriately.
Different plants need different levels of moisture. Succulents, like hens and chicks, and stonecrop rarely need watering. In contrast, big leaf hydrangeas and dwarf giant papyrus need water very often. But, most plants are somewhere in between and will thrive if you apply the knuckle test regularly. By knuckle test, I mean that, after the first watering, stick your finger in the soil every day or two and water only when you don’t feel moisture by somewhere between the first and second knuckle, depending on where the plants’ water needs are on the continuum. Remember, most plants need the top inch or two of the soil to dry out between waterings.
Similarly, plants won’t reach their full potential if you don’t feed them. Less expensive potting mixes use synthetic time release fertilizer, advertising that no fertilization is necessary for three to six months. (The outright cheap potting mixes contain no nutrients at all.) But, better potting soils use purely organic ingredients, with nutrients that are gentler and more accessible to the plants. Even the Fox Farms mix with the longest nutrient charge only provides nutrients sufficient for the first 4-5 weeks.
So, you need to fertilize, and, when you do, use a high quality organic fertilizer, a granular like Happy Frog All Purpose or a Liquid like Fox Farms Big Bloom. For all of my own personal container arrangements, I sprinkle a teaspoon full of Happy Frog All Purpose organic fertilizer once weekly.
Remember, you can always come to Urban Earth for help. We’ll help you design your arrangements at no charge and we’ll even plant them for you if you bring your containers or buy containers from us and have the means to transport planted arrangements!
The author, John Jennings, has been manager of Urban Earth Garden Center since June 1, 2016. Before that he was a self-employed landscaper for 8 years, having worked as both a real estate lawyer and a drug counselor in previous lives. He grew up in the South Carolina low country, learning to garden in the fertile soil of Copes Island, a small barrier island near Beaufort, in Jasper County. John is a graduate of the McCallie School, the University of Richmond, and the University of Memphis Law School. If you read this blog entry, please email the author at firstname.lastname@example.org and let him know what you think.