Choosing and Combining Plants for Container Gardens
Whether it’s a question of space or interest, container gardens are everywhere. Maybe it’s because they are so much fun to create and offer immediate gratification.
There are no “rules” for designing a container garden, except to give the plants what they need to thrive. However, there are certain design principles that can be scaled to container size and make creating effective container gardens an art. Think of them as Rules of Thumb, not “rules” per se.
Create Contrast and Balance
The first things to consider are balance and contrast.
- Plants should be sized to the pot and pots should be sized to the site. Small plants will be lost in a large pot, just as small pots will be lost on a large deck.
- Plants shouldn’t be more than twice the height of the pot or 1 ½ times as wide.
- Simple plants show off an ornate pot, flamboyant plants are showcased by simple pots.
- Have at least one tall plant, one filler and one trailing plant in a pot, or simply one plant per pot.
Sometimes it’s nice to have just one type of plant per container. Bold plants, like zonal geraniums (Pelargonium), look very nice on their own. You can always group several pots together.
Keep Color in Mind
Color is of primary importance.
- Suit your choice of colors to your site.
- For drama and impact, go for contrast (colors opposite one another on the color wheel).
- For harmony and tranquility stay with one color in different shades, like lavender, lilac, and purple.
- To show off the color of the container, don’t hide it with trailing plants.
- Use foliage for color
Build Bones & Focal Points
Container gardens are the perfect place to experiment and have fun. Use whatever plants you like. Mix in perennials, trees, shrubs, houseplants, vegetables, and herbs. Use whatever strikes your fancy as a container. If it doesn’t have drainage holes, plant in plastic pots and place the pots inside the container. Include garden art in your containers or groupings. And place pots anywhere there’s an open space: on the deck; the front steps; in holes in the flower border; or create borders and screens with potted evergreens or bamboo. If you don’t like what you’ve created, take it apart and start again.
- Use foliage as the bones of your container garden. Find interest in the color, texture, and size of the leaves. For instance, coleus for color, grasses for spiky airiness and Hostas for bold, textured leaves.
- You can create a focal point within a mixed container with height, bold leaves or striking color. For instance, phormium for height, hibiscus for striking color, elephant ear (Alocasia esculenta) or cannas for drama.
- Create a focal point with a grouping of containers, each with one large plant, like a pot of black bamboo, a bugmansia and some Gartenmeister Fuchsias.
Tall Focal Points or Solo Performers
Container gardens can look one-dimensional without a tall plant or two to provide some height. Don’t feel restricted to only the spiky Dracena on sale with the annuals at the plant nursery. Here’s a list of tall plants that would be perfectly at home growing in a pot. Your choice of plants is only limited by the size of your pot. Here are some tall plants to consider:
- Common boxwood (Buxus sempervirens)
- Elephant Ear (Alocasia esculenta)
- Monterey cypress (Cupressus macrocarpa)
Filler Plants for Containers
Good garden design relies heavily on the choice of filler plants. Filler isn’t a very respectful term, but filler plants can make or break your garden. They need to perform well over a long period of time and complement each other while highlighting the focal points in your container garden. Great foliage is often the key to a great filler plant. Colorful or textured foliage provides interest all season. Here are some to consider:
- Agastache foeniculum (Anise Hyssop)
- Celosia (plume flower)
- Coleus (Solenostemon scutellarioides)
- Lantana (Lantana camara)
- Ornamental Cabbage and Kale
- Senecio cineraria (Dusty Miller)
- Swiss Chard
Trailing plants for Containers
Even the nicest container garden is softened and somehow made more cohesive if there are plants trailing down its sides. Luckily plant breeders have been developing better and better choices of trailing plants. A great trailer for a pot is one with a long season of bloom, that doesn’t need immediate deadheading. Many annuals do better in either cool or warm weather and can be swapped out when the weather changes. Here are some trailing plants to consider:
Plants in containers are a great way to plan your garden. Here are techniques to help you design beautiful containers and keep them looking good.
Welcome to Larry Hodgson’s world
Can Two Houseplants Share One Pot?
Can two houseplants share one pot? Source: gallery.yopriceville.com, Clipart Library & beautifulgarden.org.uk
Question: I grow two avocado trees in huge pots. I wondered if it would be possible to plant my aloes in the same pots, at the foot of the avocados? That would save a lot of space and it seems to me that the effect would be very attractive. What do you think?
Answer: Your question brought up an interesting thought. Why is it that we traditionally grow each houseplant in an individual pot? After all, we don’t do so outdoors. We regularly mix and match plants in flower boxes and containers, in flower beds as well. Yet with houseplants, it’s usually: one plant per pot, even though there is no logical reason we couldn’t mix houseplants together too: it’s just a question of long-standing habit.
Compatibility is the Issue
Of course, the secret to success with mixed pots is that the plants have to be compatible, with similar or identical needs.
This mixed container is doomed to fail. The poinsettia and Norfolk Island pine could share a pot, since they have similar needs, but the selaginella (the mosslike plant) requires high soil and air humidity that others can’t handle. Source: statebystategardening.com
You’d have a hard time keeping a desert cactus, which prefers full sun and soil that dries out thoroughly between waterings, and a maidenhair fern, which prefers moderate to low light and soil that is constantly moist, happy in the same container. Nor should you try planting together strong, invasive plants with slow-growing or fragile ones, plants that need a long period of dry dormancy with plants that grow year-round, plants that require a lot of fertilizer with plants that prefer nutrient-poor soil, nor plants that differ in soil type, temperature, light needs, etc.
Kalanchoe daigremontiana gives off products that can actually poison the plants it grows with. Source: Alina Zienowicz, Wikimedia Commons
There are even allelopathic houseplants (Kalanchoe daigremontiana, for example) that render the soil in which they grow toxic to many other plants and are therefore never good buggy buddies.
That said, there are many houseplants that actually do share many of the same requirements. So many common varieties like or at least tolerate average light, average air humidity and average watering—philodendrons, scheffleras, spathiphyllums, etc.—and therefore, unless they have some other incompatibility, could certainly share a pot.
Succulents can usually share a pot, but if you add cacti, you’re asking for trouble! Source: The Urban Wife
Nor is there any problem growing most succulents, such as sedums, aeoniums, euphorbias, crassulas and echeverias, in the same pot, since almost all like full sun, tolerate dry air and prefer soil that dries out between waterings. But if you add a desert cactus to the mix, even if this is currently done commercially (unfortunately), it often leads to disaster, as least in the long run. That’s because most cacti really only do well with a long winter dormancy under cool, dry conditions, while “other succulents” usually don’t like things quite that cold and dry.
In other words, combining different plants in one pot is possible, but it can be complicated.
Can aloes share a pot with an avocado? Source: gallery.yopriceville.com, Clipart Library & beautifulgarden.org.uk
At first glance, the combination you suggest would not seem doable. The avocado (Persea americana) is a tree native to the tropical rainforest (i.e. jungle) and prefers soil that is always at least a bit moist, plus high atmospheric humidity at all times. The medicinal aloe (Aloe vera), on the other hand, comes from an arid environment, where the air is dry and the soil receives no water for months on end. Growing them together would seem to be a really bad idea.
That said, the aloe is an extremely adaptable plant, much more so than the avocado. It’s been grown as a potted plant for almost 6,000 years and seems to have learned to live with human vagaries. Yes, it prefers sun and soil that is on the dry side, but will adapt to medium or even low light and soil that is never totally dry, although you can’t leave it soaking wet for weeks at a time. Although it was designed by nature to tolerate dry air, it doesn’t require it and it won’t react badly to the efforts you put into keeping the much more finicky avocado happy. And both do like warmth year round, so they have at least one thing totally in common.
So yes, I think you could grow both together. It’s a borderline combination, but as long as you watch your watering and let the soil nearly dry out before you water, you ought to be able to let aloes share the big pots of your avocados.
Question: I grow two avocado trees in huge pots. I wondered if it would be possible to plant my aloes in the same pots, at the foot of the avocados? That would save a lot of space and it seems to me that the effect would be very attractive. What do you think? Dominique…