Getting the aesthetics of a container garden right is not a matter of trial and error. It’s all about getting the correct mix of small and large planters, and their position within the space. Small planters are not a problem, as they can easily be moved around and placed wherever needed. The issue most container gardeners have is with the large planters. They have to work as part of the planting in the garden, and also be mobile enough that you don’t need a forklift truck to move them around when you want to change the arrangement. So, how do you make the most of large planters in a backyard, patio or garden?
The bigger the planter, the heavier it’s going to be once it’s filled with soil. That has the knock-on effect of making it more challenging to move around and less easy to place on balconies or patios where there may be problems with weight. That’s why you should try and fill the bottom of your large planter with some lightweight material, to decrease the overall weight, and help with drainage. I’ve heard of people using plastic milk or soda bottles to occupy the bottom half or third of a planter with the rest being filled with soil. There are other products, such as those expanded polystyrene chips, which will also do the job and work like a pebble drainage layer at the base of the pot, without the weight.
Don’t forget you will be watering the soil in the planter, and that makes things a lot heavier. The more earth you have, the more water it will absorb, and the heavier your large planter will become. It’s also a good idea to place a membrane between the lightweight filler in the bottom of the planter and the soil on top. This will stop the earth from sinking through to the bottom when you water, and make cleaning up at the end of the season a lot easier.
I should point out at this stage that the shape of your large planter may also have some bearing on what you do. I have some planters that are like an upturned cone, where the base is narrower than the top. In windy conditions, they can sometimes blow over, as the planting on top acts as a sail.
The larger the pot or planter, the more critical it is to pick out the best plants for the shape and size of the container. It’s so easy for a plant to get dwarfed or lost in a large planter. Professional garden designers use the ‘thriller, filler, and spiller’ rule to make the most of large containers, giving them a stunning and cohesive look.
For a thriller plant, look for something dramatic, either with color or shape. Large-leaved plants like banana or palm work well, so do shrubs and small trees. If you pick a perennial plant, then there will be something to look at during the winter too. If you have tall planters, think about plants that can spill over the side and soften the edges to make them look more natural. Or in the case of large low-lying planters, consider ground covering plants and succulents that can give added style to your garden.
A Good Start
Whatever plants you choose for your large planters, give them a good start with the best potting soil you can find. Add your fertilizer to the mix, and don’t buy the compost with fertilizer already added. By mixing your own, you make sure the mix is thorough and in the right proportion for the type of plants you intend to grow.
Always ensure there is enough depth of soil within the planter for the roots to grow.
Maintaining the Look
You want your large planters to always look their best, so make sure that any spent flower is removed. Go around and deadhead at least once a week to remove the old growth. This will keep your planter looking neat and tidy, and also promote new blooms by stopping seed production. A large planter needs to look full, and that comes with pinching back the plants to make them bushier. Careful pruning will encourage plants to grow outward rather than upward, giving a full body to the plant rather than having it look spindly.
Adding fertilizer when you plant is not enough. A regular feed with a liquid fertilizer every couple of weeks should provide your plants with all the nutrients they need to thrive. Don’t forget to water your planters as regularly as possible. If your large planters are in direct sunlight, you may have to water once or twice a day in the summer months.
If you have lots of top growth, this can act as an umbrella so rain or spraying with a hose will not get enough water to the roots of the plants. If you’re like me and often forget to water, then consider putting in an automatic watering system. You’ll know when the plants have been watered enough when drips are coming out drainage holes in the base of your container.