Container Planting Made Simple!

Container gardening is a fun and creative way to add interest to your outdoor space and add year round interest. There are some basic concepts to know to ensure the success of your planting. While there are many different types of materials used for planters, some are better used than others, depending on your location and hardiness zone. First, there is concrete, which is attractive, durable and can take just about any type of weather. It is important to note; however, that concrete could be quite heavy. Terra-cotta or clay containers are very attractive, and excellent for warmer temperatures, but should not be left outside during winter in colder climates, as they are somewhat fragile and can chip easily. I bring mine indoors here in zone 7 once the temperatures drop to below 50 degrees to prevent that from happening. An alternate is a durable form of wood, such as cedar or non-treated pine, which will last for years to come. To prolong the lifetime of your planter, brush surfaces with a clear waterproofing sealer meant for outdoor wood. My favorite and most often used materials for containers include resin, fiberglass or plastic, all which will last for several seasons, are less costly and provide an attractive look. Many resin planters today look just like real concrete and add a nice touch to the garden.

Figure 1: Left to Right-Variegated Boxwood, Columnar Juniper ‘Blue Arrow’ and Chamaecyparis ‘Nana Lutea’

When choosing your plants, try to combine various plants for their interest, whether it be for foliage, blooms or other characteristic. In most planter combinations, the three basic elements include the “thrillers”, “fillers” and “spillers”. The “thriller” is known to add height and make a bold vertical statement. In the container planting above (Figure 1), the columnar juniper takes the role of “thriller”, making a statement and drawing the eye into the center. “Filler” plants are the more rounded selections that are usually placed around the main focal point and add a look of fullness to the planter. “Spiller” plants are added to hang over the edges of the container to give a more flowing look. The “fillers” in the above planter and in Figure 2 are the rounded boxwood and cypress, with a Dwarf Alberta Spruce as the “thriller’ in Figure 2. In Figure 3, three Mondo Grass make a simple planting with foliage spilling over the edges of the container. In Figure 4, there is a similar look with Black Mondo Grass on one side and Golden Japanese Sedge on the other, with Heuchera ‘Caramel’ for color in the center.

Figure 2: Same Planter as Above with Dwarf Alberta Spruce in Center

I for one like to enjoy my container planters all year long, so I often use a combination of evergreens, which can be appreciated not only during summertime, but in every season, including winter. The key is to choose plants which are at least two zones hardier than your location. I use plants which are cold hardy down to at least zone 5, since I am located in zone 7. This ensures that should the winter temperatures be colder than expected, the plants will survive. I also tend to keep the planters in a more sheltered area, such as near the house during the colder winter months. They receive regular watering from rain and or snow, but if there is a dry period, I will make a point of keeping the containers watered at least twice a month.

Figure 3: Ophiopogon planiscapus ‘Nigrescens,’ (Black Mondo Grass)

Figure 4: Left to Right: Black Mondo Grass, Heuchera ‘Caramel’ and Japanese Golden Sedge

Figure 5: Dwarf Alberta Spruce (center), Thuja occidentalis ‘Filiformis’ (Threadlike Arborvitae) left and right and Chamaecyparis ‘Nana’ (front center)

When it comes time to plant your container garden, I recommend a light, peat moss based all-purpose mixture, which will supply good drainage. Be sure there are adequate drainage holes for excess water to escape and that the container drains freely. I do not add rocks to the bottom of the pot, since I have found they can end up doing more harm than good, clogging the planter and not allowing water to drain. When planting, very gently loosen the root ball around each plant to prevent it from becoming root-bound and plant slightly higher than the soil level to allow for watering and top dressing or an additional layer of mulch, which will help to regulate soil temperature. Be sure that the plant is no deeper than the container it came in. Water right after planting and keep the container evenly moist, but not wet. For point of reference, the planter in Figure 5 measures 20 inches in diameter, while the smaller planters (Figures 1-3) are 18 inches long by 8 inches wide and Figure 4 measures 20 inches long by 8 inches wide.

For another type of look, try filling a terra-cotta pot with a variety of succulents (below) to create these sun-loving succulent planters or make a simple combination of various types of Coleus (bottom figure) for a shade setting. These are both fun and easy to create and will add interest all season long, until the temperatures freeze. I have found the succulent planters to overwinter just fine indoors alongside a sunny window or in a heated garage with some sunlight.. When it comes to selecting, I simply go to the nursery, choose my container and select succulents or Coleus that range in size, shape and color and always choose something that strikes my attention. Lay out the plants in the pot and give allowance for room to grow. The moral of the story is to have fun, get creative and keep in mind…”thrillers”, “fillers” and “spillers”!