Looking to brighten up your space with stunning annual flower containers?
Creating great planters involves combining container choices, soil quality, and plant quality with design, planting technique, and maintenance care. If you’re looking for practical ways to ensure your annual flower containers are able to thrive, here are 8 key tips to help your plants flourish all season, so let’s dig in!
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1. Know Your Purpose
The first step to any well executed project is to know your why, or do a quick needs assessment.
Decide where you’d like to place your planter and why you’d like it there.
Would you like your container to create a sense of privacy, add a burst of colour to a shady spot, or accentuate the entryway? Perhaps you’re aiming for a warm, inviting atmosphere to greet your guests, or a tranquil, calming effect. Or maybe you want your container to beckon visitors to sit and relax.
The answers to these questions will guide your plant choices and design decisions.
2. Know Your Gardening Space
Next, get to know your gardening environment. This will drive your plant selection.
Figure out how many hours of direct sunlight a space receives and watch how the sun moves through the area. Some areas get little, some get none, and others get morning, afternoon, or late afternoon and evening sun.
Ask questions like: does the sunlight filter through leaves when it shines on your space? Are there any structures that block the sun?
And explore how wind moves through your growing space. These answers will ensure you’re picking plants that will thrive in your space.
3. Container Choice Matters
Select containers that complement your design and decorating style yet serve the function of accommodating the needs plants have to grow well.
Be sure that they have drainage holes on the bottom and find some drainage plates to catch the water.
If they don’t have adequate drainage, you could place a 10-15 cm (4-6″) layer of rocks at the bottom to help facilitate drainage, but this isn’t my favourite alternative. I’d rather grow in pots with drainage holes and use drainage plates.
Pot size matters. Consider the mature growth size of the plants you plan to use and find a pot that will accommodate them. Avoid overcrowding and competition, which will adversely affect plant growth.
Plants will always grow to their pot size. If a pot is small, the plants will stay small because of limited available resources like soil, water, and fertilizer. The larger the pot, the more space, water, and nutrients will be accessible for the plants to grow.
Consider container materials as well. Lightweight and fibreglass pots are great for mobility, while terracotta and ceramic pots offer more weight to anchor the planter in place and give a classic design touch.
4. Use High Quality Soil
Soil is the foundation for growing healthy plants. Invest in high-quality potting soil to promote healthy root growth and hold water and nutrients well.
I avoid soils that have added fertilizer because it’s hard to tell exactly what it contains or how it will affect plant growth, so I prefer to add fertilizer regularly throughout the growing season.
I often start out with an easy-to-find brand of potting soil, like ProMix BX or ProMix HP (unsponsored), which can be purchased at most garden centres.
Most potting soils have a peat moss base. I like supplementing potting soil with compost, worm castings, vermiculite, and perlite to boost aeration and nutrient and water-holding capacity.
Compost is magic. Compost is a natural substance that holds water and provides nutrients.
I always premoisten the potting soil before placing it in the container. This gives the soil a hydrated jump start and makes it easier to keep the pot watered.
I place the soil in my wheelbarrow and water the top generously and gently. Then, I mix the water in my hand until the soil holds together when I squeeze it in my fist.
Related posts: Perlite vs Vermiculite: What are the Differences?
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5. Use Quality Plants
Kickstart your container off with vibrant, healthy plants from a reputable source.
It is important to choose plants for a planter with similar light and water requirements. This will ensure that all the plants in your container get the right amount of sunlight and water, promoting their healthy growth and making them good pot mates.
Look for healthy, robust plants with deep green leaves unless they are chartreuse or another colour naturally.
I like to choose stocky plants, avoiding stretched and spindly ones, which signal growing strain.
I often lift them gently from the pot to check the roots. (That’s the greenhouse girl in me.) Roots should be healthy and white. Dark, slimy roots are a sign of a compromised plant.
Also, check plant hydration. Wilted plants indicate stress, which could be simply a lack of water, but it could also be wind or sun stress.
6. Design with Purpose
How the plants are arranged in the planter depends on how the container will be viewed, so take some time to determine where the container will sit and be seen.
Some questions to ask about container orientation are:
• Will the container be up against a wall or fence and just viewed from the front?
• Will it be in the middle of a space where it will be seen from all sides?
• Or will it sit in a place where three sides will be seen?
Faced arrangements are seen only from the front, so taller plants should be planted toward the back, with fillers in front and trailing plants spilling over the front edges.
If the planter is seen from all angles, it will need to be a rounded arrangement with the tallest plants in the middle, with the other plants arranged around this focal point and the spill over the pot’s edge.
Experiment with colours, textures, and heights for visual interest. Opt for a cohesive colour palette and vary textures to keep things interesting.
Thrillers, Fillers, and Spillers
Thriller, Filler, and Spiller combinations are a well known and effective planter design strategy.
Here’s a rundown on Thrillers, Spillers, and Fillers, to help you create a well-balanced container.
The Thriller
‘Thrillers’ are tall, stately plants that give height and structure to a container. They draw your eyes upward and define the high point, or apex, of a container planting.
Examples of Thrillers are Cannas, Dracaenas, Ornamental Grasses, or trellises with climbing vines.
The Fillers
‘Fillers’ are medium-sized & plants that fill in the middle portion of the planter.
Begonias, Hostas, Impatiens, Coleus, Geraniums, Gazanias, Marigolds, Nasturtiums, Petunias, Salvia, and Zinnias are examples of fillers.
The Spillers
‘Spillers’ are plants that cascade over the edge of the container, like Sweet Potato Vine, Creeping Jenny, or Trailing Petunias.
Spillers extend and lengthen the container planting. When I plan fillers for a container, I usually choose 1 foliage (leafy) plant and 2 flowering plants, but that can change if more foliage or flowers work better.
More examples of Spillers include Bacopa, Black Eyed Susan Lamium, Nepeta, Kenilworth Ivy, Lamium, Million Bells, Silver Nettle Vine, Scaevola, Spanish Daisies, Sweet Potato Vine, and Trailing Verbena.
The possibilities for creativity with the Thriller-Filler-Spiller system are endless! Just make sure to match plants with the same sun and shade exposure so they can all grow and thrive together in the same pot.
Related:
- Planter Box Design Strategies,
- 6+ Front Door Planter Ideas to Make Your Entrance Shine
- Plant Pairings Chart for Containers in Sunny & Shady Growing Spaces
7. Planting Techniques
• Arrange the Plants While in Their Pots
Before planting, I arrange the plants on top of the soil while they’re still in their pots.
This makes it easy to visualize the end arrangement, and moving and adjusting the plants without damaging their roots is simple.
• Water the Plants Before Transferring to Planter
Once I have finalized my design, I double-check that all the plants are well watered. This gives them a hydrated start, decreases their stress, and helps the roots slide out of the pots.
Dry roots stick to the pots’ sides, making it more difficult to dislodge them.
Plant the Thriller First
I always plant the Thriller first, whether it’s at the back or middle of the pot.
I slip each plant out of the pot. If the roots get stuck, I squeeze the sides of the pot a bit, and they should come out.
Then, I loosen the roots a bit, dig a generous hole in the soil, gently place the root ball in it, and fill in around the roots.
There’s no need to firmly push the plants down or pack the soil; both of these will squeeze the air spaces needed for holding water and root metabolism.
Plant the Fillers and The Spillers Next
Next, I plant the Fillers and follow with the Spillers as I reach the edge of the pot.
I water the planted container as soon as I am done planting as it stresses plants to have their roots messed with, and the additional water facilitates a speedy adjustment to their new habitat.
I don’t fertilize at this time because the fertilizer could burn the microscopic root hairs right after transplanting.
And then, I love to top my planters with a little mulch.
Related: How to Use Mulch in Planters and Hanging Baskets, Eight Tips for Transplanting Plants in Your Garden,
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8. Planter Maintenance
Regular care and maintenance are what get annual containers through the growing season with daily checks, watering, fertilizing, and deadheading..
I like to use the acronym TEND to describe 4 key steps in caring for planters:
• T – Take a Good Look
This is an assessment step, giving plants a daily look and digging deeper if needed
• E – Ensure Adequate Moisture
This step is all about keeping your container well-hydrated
• N -Nutritional Needs are Met
This is about fertilizing to keep your plants thriving
• D – Deadheading
This is a maintenance step about deadheading, if necessary and trimming plants to keep them in top shape.
Use this link to download your free Container Tending Guide with all the details on annual container maintenance.
Related: How to Keep Hanging Baskets & Flower Containers Thriving all Season
Let Your Creativity Blossom with Annual Planters!
Creating stunning annual flower containers is a rewarding endeavor that can significantly enhance the beauty and ambiance of your outdoor gardening space. By following my eight practical tips, you can be sure to enjoy a balanced and flourishing arrangement.
Embrace the joy of gardening, and let your creativity shine as you craft unique arrangements that reflect your personal style and bring a splash of color and life to your surroundings. Happy planting!
More to Explore
- Top Alberta Balcony Garden Ideas [+ Free Downloadable Chart]
- 4+ Ways to Grow Great Fresh Herb Planters in Alberta & Everywhere Else
- The Secret to Growing Great Strawberries in Planters and Hanging Baskets
- Home Garden Irrigation Options
© Sharon Wallish Murphy © Gardening with Sharon
