Gardening Sweet Spots
By Donna Hessel
Living Flower Arrangement vs Traditional Container Planting
There are two basic ways to plant a container. The “living flower arrangement” is what is often seen pre-planted for sale in garden centers… as many plants as possible crammed into the container to completely fill it out to look immediately amazing.
That’s great if something that looks “finished” for a special occasion is the objective. Traditional container planting is when there is enough room between plants so the planter looks full after several weeks of additional growth.
Most of the time, traditional planting is the way to go. Generally, using three or four plants in 10-12 inch planters, four to six plants in 14-16 inch planters and six to eight plants in 16-20 inch planters will fill out containers nicely while allowing room for the plants to grow without excessive crowding.
The number of plants used can be adjusted up or down by considering the vigor and final size of the plants. Plants that are more compact and have an upright nature may take more than the recommended number to make the planter seem full. The size of the plants being purchased also needs to be considered. More plants in six-packs will be needed than plants in four-inch pots, and even fewer plants will be needed if plants in gallon-size pots are selected.
Information included on the plant label is a good clue as to the number of plants needed. “Spacing” refers to spacing for in-ground planting. However, it is one way to estimate the final size and vigor of the plant being purchased and how many will be needed to fill a container. Plants that have a tighter spacing recommendation are generally smaller and less vigorous. A larger spacing recommendation means plants will be larger and more vigorous.
Thriller. Filler. Spiller.
The most common way to begin designing a container is to use the “thriller, filler, spiller” concept, which will create well-balanced and attractive arrangements.
Thrillers are plants with height that add drama and a vertical element to the combination. They can be either flowering or foliage plants or ornamental grasses. Thrillers are generally planted in the center of the container if it will be viewed from all sides, or in the back of the container if it will be seen from only one side. One striking plant in a container can make a dramatic statement.
Filler plants tend to be more rounded or mounded and make a container look fuller. Filler plants are generally placed in front of or around the selected thrillers. They should be placed midway between the edge of the container and the thriller variety, surrounding the thriller if it is in the center of the arrangement.
Spiller plants are added last. These are trailing plants that hang over the edge of the planter. They are placed close to the edge, on all sides if the container is in full view, or in the front of the container if it is seen from only one direction.
It is best to leave some space between the top of the soil and the edge of the pot. In small containers, half an inch is good, but for larger containers, an inch or even two inches of space should be left. This “headspace” helps to keep the soil from washing out of the container and it also channels the water into the container. An inch or two left between the edge of the pot and the edge of the plants will give the plant room to send roots out in all directions.
The thriller, filler, spiller concept doesn’t work well in hanging baskets. Using a mixture of spillers and fillers, or just spillers will make the most attractive hanging baskets.
Planning Color Combinations
The easiest container to design is choosing a single plant variety to fill the pot. “Mono-culture” containers are great for showcasing a special container or creating a pop of color. Any type of pot from classic to colorful to a found object (basket, odd worn work boot, etc.) can work as a container if the plant selected has staying power and fills out the container.
The next simplest design is “mono-color.” Mono-color combinations use plants with at least two different shades of one color. Selecting a container in a neutral color, whether white, terra cotta, black or silver, or selecting a container in a color that coordinates with the color of the plant, enhances the arrangement.
Referring to a color wheel when selecting color combinations is helpful.
The pot color and the background behind the container can be important considerations in selecting plants. Consider them a part of the color scheme. One way of combining color is selecting analogous colors. Analogous colors are next to each other on the color wheel and mix together easily. Some examples of analogous colors are yellow-orange, orange-red, violet-red, blue-green, and blue-violet. Analogous colors can be bright or muted, but they are always next to each other on the color wheel.
Another way of combining color is to select complementary colors. These are colors that are opposite each other on the color wheel. Complementary colors are red-green, orange-blue and yellow-violet. Using complementary colors in the container arrangement will create drama and the color contrast will make both colors pop. Color intensity of the flowers is important to consider when using a complementary scheme. Similar color intensity of flowers will work best.
A triad color scheme uses three colors that are spaced equally distant on the color wheel. This scheme is more difficult to accomplish since several different colors are selected. Two triads to try are red-yellow-blue or violet-orange-green. Colors are classified as either hot or cool. Hot colors are red, orange and yellow. Cool colors are blue, pink and purple. Color schemes can be selected to complement a specific area of the yard or garden. Hot colors work great in containers placed to focus attention — at doors, walkways and in corners of the garden to call attention to an area. Cool colors evoke calm and tranquility, best in spaces where relaxation is the objective.
Contrasting foliage colors and textures in color-matched neutral containers
make a striking presentation.
Neutral colors – white, black grey, silver and shades of brown – can also be added to a scheme. Green is considered a garden neutral and green foliage can be used to add dimension to an arrangement. Plants with dark foliage create both drama and contrast. Silver and chartreuse foliage harmonize well with most flower colors, and silver looks great with soft colors. Chartreuse foliage mixed with reds, oranges and yellows creates a tropical feel but is also a dramatic contrast with dark colors.
A plant with dark foliage and bright flowers in a neutral container placed in the garden will call attention to that area.
One last element to consider in container design is texture. Both foliage and flowers have texture. Texture refers to the size, shape and surface of leaves or flowers – hairy, smooth, crinkled, etc. If the texture of all the plants in a container is similar, the plants will all blend together. Using plants of different sizes, shapes and textures will result in more contrast and a more attractive arrangement.
Choosing Container Companions
- Select plants that prefer similar growing conditions. Sun? Part shade? Full shade? Read the label before buying the plant! Check to see how much water each plant prefers. Avoid pairing plants that need consistently moist soil with those that are drought tolerant.
- Look for plants with similar growth rates. In the plant label description, assume “vigorous” means grows quickly. “Petite” or “tightly mounded” means don’t plant with something that has a sprawling habit.
- Copy someone else’s great design. ‘Imitation is the sincerest form of flattery.’
Tools Especially Helpful for Container Gardening
Special tools for container gardening? Not really; however, that said…some basic tools and supplies can reduce the time spent tending to containers and simplify maintenance tasks. Consider these:
- Soil scoop – Definitely useful and the soil will land around plants and be less likely to be wasted.
- Hand garden fork — Helps to tease tangled roots apart before planting so roots can stretch out and grow.
- Garden trowel – An essential tool to use for filling, planting and digging out soil. A narrow pointed shape makes planting easier in tight spaces; a broader one is good for digging out old soil.
- Japanese Hori hori knife – Narrow and sharp, it’s the perfect tool for making a planting hole in an established container. The serrated edge shears overgrown roots and cuts thick tangles when emptying pots at season’s end.
- Pruners & Snips – For deadheading or cutting flowers.
- Pot feet/risers – Use to lift containers slightly off the ground so soil won’t clog the drainage hole and keep drained water from staining a surface. I save the lids from peanut butter and mayonnaise jars – they make perfect size pot feet. Blocks of wood, plastic or brick also work well.
Whew! What a lot to consider when designing containers that will evoke envy. If you’ve read to the end of this blog (thank you!), here’s the best tip of all: Click this link to Proven Winners’ “Container Gardening Recipe Search.”
Search by color scheme, container style, sun/shade requirements and more to find the perfect “recipe” for a specific container. Each recommendation includes a plant list, number of plants and how to arrange them. Recipes can be printed for plant shopping.
This makes designing enviable containers easy-peasy!
Article Resources:
Proven Winners Online Newsletter – 3/4/22
“Container Garden Design – Planting” – Kerry Meyer, Contributor
“Container Garden Design – Color” – Kerry Myer, Contributor
“Container Garden Design – Structure” – Kerry Myer, Contributor
“Container Garden Design – Foliage and Texture” – Kerry Myer, Contributor
Garden Gate Online Newsletter – 5/11/21
“Best Tools for Container Gardening” – by Garden Gate Staff
Proven Winners Online Newsletter – 3/4/22
“Five Tips for Choosing Container Companions” – Susan Martin, Contributor
Proven Winners Online Newsletter – 3/4/22
“Container Gardening Using the Thriller, Filler, Spiller Planting Technique”
Proven Winners’ “Container Gardening Recipe Search.” provenwinners.com/container-gardening/container-recipes/search
Photos courtesy of pexels.com, Proven Winners websites and Google Images
