Thriller, Filler, and Spiller
I recently held a workshop at CAMP Rehoboth where I talked about, among other things, container planting.
The beauty of planting in pots, baskets, and boxes is that anyone can do it, and in the smallest of spaces. This allows those of us, me included, who only have a small patio or balcony, a chance to bring a little nature closer to us.
Start by choosing your container. A simple terra cotta pot, a hanging basket, an old boot, almost anything. Then, choose your plants both based on size (proportional to the container), and where it will be placed (full-sun, part-sun, or shade.) For example, don’t pick plants that will become too big for the pot and top-heavy. They are more likely to be blown over in high winds and will look awkward compared to the container. Alternatively, don’t place a barrel full of hosta and astilbe on your south facing patio as they need shade and the sun will be bad for them.
Containers can be filled with one type of plant for a big impact and then grouped with other containers of differing plants. Or, a container can have a mix of plants. When this is done, I find that a certain guideline should be followed: the container should have a “thriller, a filler, and a spiller.”
Meaning, the pot should have a tall or larger plant that is a focal point of the design—the thriller. The next level down is the filler to “fill-in” around the base of the thriller and provide color and texture. Lastly, provide a spiller around the edges of the container with plantings that creep or spill out over the edges and complete the magic show.
Next comes preparing the pot for the plants. Any container needs proper drainage. Most commercially available containers have pre-drilled holes or openings in the bottom. If you are using a non-traditional container, make sure there are areas where excess water can escape. If you have pots with no drainage, you will fail at growing anything in them. The roots will inevitably rot because of sitting in water.
It is always a good idea to include extra drainage items in the bottom, such as old pot shards, pebbles or stones, or even the upside-down plastic containers that the plants come in. This is a trick I have done in the past in very large containers.
I place some of the plastic containers in the pot upside-down, in order to take up some volume in the container. This will help keep the pot lighter and easier to move around. This will not work if you are planting larger specimens that need more soil for their roots.
Let’s talk about soil. We could chat for hours on soil mediums, vermiculite, perlite, yadda, yadda, yadda. But I find that a 50-50 mix of soil-based potting mix and a lighter peat-based mix works just fine. There are also special mixes available commercially for almost any condition.
If you are afraid of your containers drying out or missing a watering cycle, there are also special gel crystals that can be mixed into the soil which swell with water and then release it to the plant over time. To be honest, I have never tried these, so I do not know how well they work. If anyone out there has an opinion on them, let me know.
Next is planting. It’s a good idea to have the plant being transplanted to be moist. Gently remove the plant and loosen the roots on the bottom and sides. Place the plant into the container and make sure the soil line is at the same level it was taken from. Gently press around the base of the plant to remove any large air pockets. Then, water the container well and you’re off to the races.
Watering is essential for containers, especially in the heat of summer. Flower boxes and hanging baskets, or anything raised off the ground, dry out very quickly and may need watering twice or even three times a day in extreme heat. A fertilizer can be routinely applied throughout the growing season, since nutrients can leach out of containers easily.
A final thought on containers: they can be temporary pieces of beauty with items changed throughout the year or can be a more permanent feature filled with perennials, shrubs, or even trees. Whichever way you style the containers, make them your own. There are no rules when it comes to your garden!
Enjoy, and let’s garden together! ▼
Eric W. Wahl, RLA is a landscape architect at Element Design Group and president of the Delaware Native Plant Society.
Images courtesy of Buck Walter, Walter’s Nursery in Point Pleasant, PA