Container Planting & Design
One of the more perplexing questions people have that are new to container gardening is how many plants should be included and where should they be placed in the container? The truth is that plants are flexible and there is no "right" answer. There are, however, guidelines that can help you decide how many plants to use and where to place them.
Living Flower Arrangement vs. Traditional
There are two types of plant combinations, a "living flower arrangement" and traditional planting. A "living flower arrangement" is when you place as many plants as possible into each container. This allows the container to look full immediately after planting. However, since "living flower arrangements" are crowded they tend not to have as much longevity and often have a greater chance for diseases than traditional planting. "Living flower arrangements" can be really useful if you need to have a high impact container immediately, say for a party the same weekend you are planting the container.
Traditional planting is when you allow enough room between plants that the container looks full after two to three weeks of additional growth. Generally use three or four plants in 10 to 12 inch container, four to six plants in 14 to 16 inch container and six to eight plants in 16 to 20 inch container and so on. With traditional planting, you need some patience to get a completely full container. However, the plants will be healthier because of better root growth and less crowded containers also have better air flow around the plants, helping foliage dry faster which will decrease the chance for diseases.
It may take more than the recommended number of plants to fill a container if the plants are more compact and upright. Pansies are an example of a compact, upright, slower-growing plant that are fantastic for adding color during cooler growing seasons. However, they tend to be relatively small plants and primarily grow when the weather is cool, which means they grow more slowly. Use a lot more than the recommended number of plants mentioned above when planting with pansies.
Size Does Matter
Beyond considering how large a plant will get and how vigorously it grows you will also need to consider the current size of the plants you are using in your containers. If you are starting with a four or six pack of plants, you will use more plants than if you are starting with a four inch pot of plants. If you use gallon sized plants, you will need fewer plants.
Spacing instructions are often included on plant tags. This refers to the preferred spacing for in-ground planting. However, you can use this spacing information as a way of estimating final size and vigor. Plants that have a smaller spacing recommendation are generally going to be smaller and less vigorous and those with a larger spacing recommendation are going to be larger and more vigorous.
Now that you have determined how many plants to use in your container it is time to start placing them in the container. It is best to leave some space between the top of the soil and the edge of the container. In small containers half an inch is recommended, but for larger containers leave an inch or two. This is called headspace; it helps to keep the soil from washing out and helps channel water into the container, making watering much easier. Without headspace, water would simply run out of the container.
Once you have added potting soil, it is time to start arranging the plants within the container. It is best to leave an inch or two between the edge of the container and the top of the soil from the plants. This will give the plant room to root-out in all directions. Now you will need to arrange the plants so each has room and the whole container is full.
Generally, if you are using three plants in a semi-circular container, you could plant one in the middle at the front of the container and the two off-set to either side at the back of the container (below, left). For a round or square container, you could plant them in an equilateral triangle within the container (below, middle) and if it is an oblong or rectangular container you could plant them in a row (below, right).
If you are using four plants in a semi-circular container, you could place three along the back with one in the middle in the front (below, left). For four plants in a round or square container, you could put them in a square formation or into an equilateral triangle and then place one plant in the center (middle photos below). For a rectangular container, four plants would work best with two along the front and two along the back in a checkerboard pattern (below, right).
For five plants in a semi-circular container, you could put one plant in the front, two plants in the middle on either side of the first plant and the last two plants at the back of the container close to each side (below, left). For five plants in a circular or square container, you could put four of the plants in a square with the fifth plant in the middle (below, center). With a rectangular container, five plants could be placed in a checkerboard pattern with three plants along the front and two along the back of the container (photo, right).
Once you plant six or more plants in a round or square container, you will probably want to plant at least three towards the outside, equally spaced apart. Place one in the center and then place the rest between the outer plants and the center plant. For a semi-circular container, place one to two plants at the front and then fill in behind with the rest.
If you are planting a mono-crop (all the same plant), you can place one plant in each spot explained above based on how many plants you have. If you are planting a combination crop (several different plants), pay attention to color, texture, habit and height when arranging the container.
As you are planting, try to space the plants out evenly throughout the planting area of the container while leaving some space between the edge of the container and the root ball of the plants. If you do that, your planters will look great!
- Proven Winners