It’s that time of year again when we stock up on flowers for our containers. And the plants always start out looking great. But in no time, the blooms fade and the stems turn long and leggy. As a landscape designer, this is the most common question I get: How do I keep my potted plants in shape all summer?
The Three-Step Rule
There are three key steps to remember when caring for potted plants. In order to grow successfully in containers, they require:
Would you go a day without water or a month without food? Your flowers depend on you to provide them with all they need. Follow these steps and you’ll have blooms all summer.
Water, Water and then Water Again
Annuals are called annuals for a reason. They have no permanent root system. In order to survive, they need a regular supply of water. In fact, shallow roots, which have limited capacity to store water, require water daily. Don’t let anyone tell you otherwise! As soon as the top of the soil dries out, potted flowers do, too.
Annuals have shallow roots that require water daily
When watering your potted plants, water at the soil level to avoid wetting the leaves. Wet foliage can encourage fungus to develop. A good rule of thumb is to water at the soil level until excess water seeps out of the pot. That way, you’ll know you’ve completely moistened all of the potting mix.
Feed For More Blooms
Even though potting mixes come packed with ingredients, containers quickly lose nutrients to hungry plants and frequent watering. As a result, potted plants need to be fed so they can keep on growing. I feed my flowers twice a month, from spring to fall, with a water soluble fertilizer.
That said, it’s important not to overdo things. Too much fertilizer will produce lots of lush foliage, but fewer blooms.
Groom To Keep The Shape
A great haircut can be transformative. And after just a few weeks in a container, flowers can start looking shaggy. You can control for this with proper grooming.
Groom your plants by regularly deadheading faded flowers and pruning leggy stems. Make sure to pinch or snip back stems to an intersecting branch at a 45 degree angle. This key task will help maintain the form of your plants and stimulate them to keep on blooming.
Below are three popular potted plants and how to keep them in shape all summer.
Geraniums
Though grown as an annual in most areas, the common geranium is actually a ‘tender perennial’, meaning it won’t survive cold temperatures outdoors. While it’s tempting to buy this beautiful plant in early spring, it’s usually best to hold off until around Mother’s Day when there’s less risk of it getting zapped by frost.
A healthy geranium has a few central stems and lots of side shoots (which is the optimum structure for a strong plant that will produce lots of flowers.) To keep your geranium looking good, prune back the central stems by about a third a week or two after potting it. This will encourage more side shoots to develop and maintain the plant’s fullness.
As the season progresses, regularly pinch the side branches of your geranium down to the angle where the branches fork. This will prevent the plant from becoming leggy. And deadhead (pinch at the base) all flower stems as soon as they have faded. This will encourage new flowering.
Petunias
Petunias quickly become leggy without some prudent intervention. They can also quit blooming almost entirely after an initial colorful flush. No worries, though. With proper watering, feeding and grooming, you can keep your petunias looking good all summer.
Like all flowers, petunias must be regularly deadheaded to encourage new blooms. However, unlike most flowers, removing the dead blooms accomplishes only part of the job. That’s because at the base of the petunia flower there is a small, nugget-sized pod that produces seeds. If you leave the pod on the plant, the petunia will stop blooming.
So in order to get your petunia to produce more flowers, remove the entire flower stem.
Deadheading the flowers (with stems) on a regular basis will keep your petunias blooming: however, it won’t solve the leggy problem. To control legginess, prune your plant every week, cutting back about a third of the petunia. You can do this by pinching branches selectively or grabbing clumps and shearing them off. Each week, cut the plant back by another third. Rejuvenating petunias in this way will encourage new stems and blooms to sprout from the interior branches.
Begonias
These bright-colored flowers require less care than geraniums or petunias, but still need regular pruning to maintain their compact shape. The same goes for the indoor varieties, by the way.
To keep your begonias looking their best, prune the outer branches (called canes) harder than the interior ones, pinching back the growing tips of new shoots to encourage new stems to develop. Prune the interior canes at varied heights and prune the outer canes at the lowest. This will encourage new growth at the base of the plant and prevent it from looking bare at the bottom.
If your begonia has lost all of its lower leaves, you can cut it back all the way to the soil. This will force the plant to send up new shoots. You can then continue pinching new stems as they grow until you achieve the desired shape and fullness.
A note on begonias, both indoors and out. They don’t like to be overwatered.