Spring is in full bloom and now is the perfect time to spruce up your entryway, porch, or patio with colorful container plantings. There are many ways to approach container gardening. Whether you’re the DIY gardener or you’d like some design assistance, we’re here to help add some seasonal vibrance to your outdoor space. A few things to consider before picking out your plants:
- What type of sun exposure will the container get?
- How easy is the pot to water and maintain?
- Which style will best complement the surroundings?
Choosing a Container
The container will set the tone for the entire project. Consider the size, shape, material, and style.
Size: Larger containers tend to be more dramatic and allow for ample space to display plant combinations while promoting vigorous plant growth—for best results, choose a container with a minimum diameter of 14–18 inches. In general, shallow bowls and small pots can be difficult to keep watered and are usually best suited for succulents or other drought tolerant selections.
Shape: Containers with narrow openings can be difficult to repot since plants are not easily extracted without damaging them. Tall, narrow pots, especially those that taper towards the bottom, tend to be top-heavy and may blow over in windy conditions, particularly if planted with taller plants or trees.
Material: Ceramic and plastic containers hold water better and tend to dry out slower than wood or unglazed terracotta pots where water may evaporate through the sides. All outdoor pots (except water gardens and bogs) should have drainage holes!
Style: Your plants and container should complement each other—start by choosing a basic design theme, such as modern, classic elegance, whimsical, northwest zen, edibles, etc. Stick with a color palette for a more cohesive container design.
Choose companion plants with similar likes and dislikes. Grouping plants together with various heights, colors, and leaf textures helps create a full, layered effect without crowding.
- Thriller: centerpiece plant; usually one per container; often an evergreen or showy perennial
- Fillers: medium-sized plants with upright, full growth habits; often foliage; plant in multiples
- Spillers: trailing plants placed at edge of pot to cascade down the sides; plant in multiples
Often, colorful early spring flowers do not continue to bloom in hot summer months; seasonal color can be planted now and later exchanged for summer bloomers. And remember, foliage adds punch and definition essential for a well-rounded combination—it’s not all about the flowers!
Thriller Plant Options
Thrillers for sun: Zonal or Fancy-Leaf Geranium, Lemon Cypress or dwarf conifer, New Zealand Flax (Phormium) or Dracaena/Cordyline Spike, Red Banana; plants used for thrillers may be evergreen/perennial or tender annuals replaced each year
Thrillers for shade: Upright Fuchsia, Coleus, Caladium, Elephant Ears (Colocasia), small lace-leaf Maple, Fatsia japonica
Filler Plant Options
Fillers for sun: grasses make great fillers; Mexican Feather Grass (Stipa tenuissima) or Orange Carex are evergreen perennials; Heath/Heathers with blooms or colorful foliage, Tender Licorice Plant (helichrysum) in pale yellow, silvery Dusty Miller; Pansies and Primroses make great seasonal color additions, but may need to be replaced during hot weather
Fillers for shade: variegated Swedish ivy (Plectranthus), Oxalis, Asparagus Fern or other ferns, Coleus (compact varieties), Impatiens, Heuchera varieties (evergreen and perennial)
Spiller Plant Options
Spillers for sun: Million Bells (Calibrachoa), Ivy Geranium, Verbena, Bacopa, Sweet Potato Vine (best in part shade)
Spillers for shade: Bacopa, Trailing Fuchsia, Tuberous Begonia, Creeping Jenny (Lysimachia), Lamium, Vinca
Container Planting Steps
STEP 1: It’s best to work with pre-moistened potting soil and to pre-soak plants before planting them into the container—toss plants (pot and all) into a bucket of water or compost tea until soil is completely saturated.
STEP 2: Fill the bottom two thirds of the container with potting soil, add fertilizer, and start placing plants in at proper soil level, beginning with the largest plant and working down to the smallest, while adding soil around each plant’s roots.
STEP 3: Be sure to leave about ¾ to one inch of space before the top edge of the container to allow water to sit on the soil surface before it gets absorbed. Once the container is finished, be sure to water it thoroughly to settle the soil.
Always Use Quality Potting Soil
If planting into a very deep container, it is okay to reuse old potting soil in the bottom third or quarter of the pot. Or if the container is intended to hold annuals that only grow for one season, it is okay to use some form of “filler” in the bottom of the pot, reducing the overall volume of soil needed to fill the container. Some filler examples include up-turned empty nursery pots, empty plastic water bottles, chunks of Styrofoam or packing peanuts, and Ups-A-Daisy pot inserts.
Do not decrease soil volume to the point that plants have minimal root space or the container becomes difficult to keep watered. Don’t forget to use fertilizer when planting containers.
Container Care & Maintenance
Watering, deadheading, fertilizing… repeat!
Watering: Learn to love it—you will likely need to water your containers at least once per day during the hottest months, occasionally skipping a day, as needed. Water most pots until it runs out of the bottom holes to be sure the soil becomes thoroughly wet. Containers in shade may need to be watered less frequently than those in more sun.
Fertilizing: Container plantings have limited resources to obtain nutrients and rely heavily on being fertilized for peak performance. Slow-release or time-release fertilizers are best added at planting time and reapplied every 4–6 weeks or according to the label (a “cocktail” of Rose Society Fertilizer 15-10-10 mixed with equal parts G&B Organic All-Purpose or Paradise Fertilizer is a great combo). As containers are watered more during warm weather, nutrients are leached out of the soil at a faster rate and should be similarly replaced. For a boost of nutrition more immediately available to plants, use a liquid fertilizer such as G&B High Bloome or G&B High Growth.
Deadheading: Most flowers bloom better when spent blossoms are removed—this process is known as deadheading. In addition, some plants will look better with occasional light trimming or pinching back to promote a fuller growth habit or to regenerate after a stressful period. And don’t be afraid to trim plants that are bullying other plants in the container to maintain balance.
Pests: Pests can be a problem; it’s best to treat for pests before they wreak havoc on your container! For example, our beloved petunias and geraniums are prone to budworm, so we spray with BT (bacillus thuringiensis, a natural bacteria that is very safe) every two weeks beginning in late June or early July to protect new growth from the voracious caterpillars. Healthy plants that are well-fed and well-watered are less prone to pest problems.
Too Busy? Consider the “Drop-In” Approach
Drop-in container plantings are ideal for garden lovers with busy schedules or for those who prefer not to get their hands dirty. This means using a plastic pot that can discretely fit inside your decorative one and planting it with pre-planted seasonal combinations! You have instant seasonal color that can be refreshed easily or switched out through the seasons.
I like to have a fresh pot of spring-blooming bulbs at my door, but once they are done flowering, I pull out the pot and switch it for one with more dramatic spring and summer annuals that will look good for months. Drop-in pots are also a great way to learn about plant combinations and to gain confidence in container gardening through the seasons.