A wide variety of cacti are available for sale in garden centres. (ALBERTA PARSONS/FOR THE SUN)
Although succulents (fleshy plants in foreground) can be included in a cacti planter, they tend to be faster growing than cacti and can crowd out cacti over time. (ALBERT PARSONS/FOR THE SUN)
Clump forming mammelaria or pincushion cacti (upper left & lower left) add variety to a cactus garden. (ALBERT PARSONS/FOR THE SUN)
The last week of March might seem too early to start planting up containers for the outdoor garden and in most cases I would agree.
One project, however, that can be undertaken at this time of year is the creation of a cactus planter; it can be planted now and when the time comes, it can be used on a patio table in the outdoor landscape.
There are a couple of reasons that you might like to create a cactus planter now, and one of them is that it will give your green thumbs some exercise in the late winter when they might be getting out of shape.
Another reason might be that the container will have lots of time to settle in and be "mature" when you want to move it outdoors.
During the winter, garden centres always have a great variety of cacti for sale, and as the production of bedding plants gathers full steam, they may want to get rid of these plants to make room for spring displays — you may discover some discount prices. Even if you don’t, there will still be a good selection of cacti to choose from and they are not expensive even at regular prices.
The first job is to obtain an appropriate container. Since it is to be used in the outdoor garden, it would be best to choose one that has a drainage hole.
When I am creating a cactus garden for indoor use, I often choose a container without a drainage hole so that I do not have to worry about water leaking out where I don’t want it.
When used in an outdoor setting, you will want the container to be able to drain in the event of a heavy rain. To facilitate good drainage, cover the drainage hole with a coffee filter or piece of newspaper so that it will not get plugged.
Use a potting medium suitable for cacti — it should have excellent drainage and not hold too much water. The best mix will contain sand and perlite but a minimum of organic matter such as peat moss.
Choosing the container first will help you to determine how many plants you will need to create your cactus garden. Do not feel that you have to fill the container to overflowing as you do with most of your other outdoor containers — cactus gardens look best when there is some space between the individual plants so that the texture and structure of each specimen can be appreciated.
Choose healthy plants that are sturdy and not at all spindly — this is after all, going to be an outdoor planter. Try to get a variety of textures, colours, sizes, and forms.
A taller columnar specimen will make a nice contrast to a mammillaria type — this is the kind of cactus usually referred to as pincushion cactus because its grows in a clump of small stems all growing tightly together to form a pin-cushion effect. Include one plant that has unusual texture, perhaps instead of needles it will have a contorted or warted surface.
Some cacti have straight, sharp needles while others have fishhook-type needles; others have few needles but what appears to be hair growing out of the upper trunk. When you go to the garden centre, the problem will not be to get a variety of cacti but rather to limit yourself to buying only the number that you need because there are so many interesting looking cacti available.
Plant the cacti at the same depth that they were planted in their original containers. Don’t pack the soil too firmly around them as it will gradually settle over time.
Water the pots of cacti a couple of days before you plant up the container and have the planting medium moist. After the cacti are planted, you will not need to water them as the soil around their roots will be wet enough and the planting medium that you used has already been pre-moistened.
More cacti are killed by too much water rather than too little. Put your cactus garden on a sunny windowsill and water it sparingly, perhaps once every two weeks.
When danger of frost has passed, you can move your cactus garden outdoors. Do this in graduated steps, giving the planter little direct sun to begin with and gradually increasing its exposure to the direct rays of the sun over a period of two weeks.
After that, you can enjoy your cactus garden for the summer, where it will add a nice contrast to all the other planters and containers. It will be unique.
Albert Parsons is a consultant for garden design and landscaping who lives in Minnedosa.
Republished from the Brandon Sun print edition March 21, 2013