Mid-Summer Container Tweaks and Hacks

Mid-Summer Container Tweaks and Hacks

The pots and boxes that Cape Cod gardeners fill in May often take on a life of their own as the summer goes on. Some plants grow gangbusters, to the point of overwhelming others in the same container. Other plants may slow down their flower production, or be producing flowers at the ends of their stems. And just about everyone has experience a “drat!” moment when they realize that their container has dried up when their attention was elsewhere for a few short days. In all of these situations, there are tweaks, hacks and improvements that can be made. Here are some 5 tips for enhancing your containers in mid-summer.

1 Fertilize

If you didn’t mix a time-release fertilizer into the potting soil, and haven’t used a liquid fertilizer yet this summer, it’s time to do so. Be sure to water your containers very well, and let that moisture saturate the rootball and hydrate the plants for at least three hours. Then mix a synthetic fertilizer according to directions, and apply. Synthetic fertilizers are instantly available to plants, which is why you’d want such a product for your plants at this time of year. Fertilize again in early and mid August.

Never apply a synthetic fertilizer to dry soil or a thirsty plant. Do not mix a synthetic product too strong. If you have some time-release fertilizer available, you can put a couple of tablespoons of this on top of the potting mix in your containers.

A synthetic fertilizer that many on our staff have used and loved is MaxSea.

2 Trim Overly Enthusiastic Plants

There are some plants that become over-achievers in our containers. If these plants look wonderful, and you love the container, then leave well enough alone. But if they dominate the pot or box in a not-too-attractive way, by all means thin them out. This may be necessary with some sweet potato vines, for example. Start by clipping off a few stems that are smothering other plants. Go slowly and pause after each stem removal to look at the container and see if you’ve removed enough. You can always go back in a few days and trim some more, but once you’ve got off the pieces, you can’t reattach them to the plant.

Here is record of the window box plantings that C.L. Fornari put on her shed this year. The sweet potato vine was the fastest to grow, and at one point was pruned and thinned so that it didn’t take over the begonias in the box. You can see in the third picture, that the thinning let that center begonia have enough light to grow and bloom more.

3 Add Ornaments To Pots and Boxes

If your containers have suffered because they’ve dried out, or if a cool-weather plant has stopped flowering because of the heat, one solution is to add something to that arrangement that draws the eye away from the problem. You might use allium seed heads, a decorative obelisk or trellis, large sea shells, vintage watering cans, or sculptures. This can be creative and fun.

Add a colorful gazing ball…or add three! You can set them right into larger pots and boxes, or get a wire stand as you see in this photo, and place them on that so that the ball floats above the container.
Got allium seed heads? Cut them from the garden and stick into a container so that they shoot up over the plants like fireworks. Some people even spray paint them…
You can make an obelisk or trellis out of sticks and poke it into a container. This is especially useful if you’ve got tall plants in that pot that are prone to leaning or flopping. A stick support is attractive, creative and is another element that can draw the eye from plants that aren’t in tip-top shape.

4 Add New Plants

If some of your plants are doing well but you’ve got a blank space in your container because other plants died, don’t hesitate to remove the problem plant and stick in something new. Just use a trowel to not only lift the dead plant out, but create a hole for the new one to be tucked in. Water well after planting and fertilize as described above.

Even in mid-July we have fresh, new annuals coming in. These can be added to containers and boxes, or planted in perennial gardens that have lost their flower-power. And the butterflies will love you if you choose some Zinnias…
Hyannis Country Garden has container and garden annuals for every color scheme.
Yikes! These boxes dried out too much in the heat of late-July, and the Browallia and one of the begonias are now toast. Rather than looking at a huge amount of sweet potato vine for the rest of the summer, I chose to take out the dried plants and stick 3 new begonias in each box.
Instant improvement! I added some more time-release fertilizer and a bit of fresh potting mix, and watered the boxes well after planting. Now I just need to be careful not to let them dry out again. I will prune back some of the sweet potato vine in a week or two.
Two years ago I planted some Lemon Slice Calibrachoa in this book, but it had some empty areas in the middle in August. Once the ornamental cabbage and dark grass came into Hyannis Country Garden, I replaced the flagging plants with those fall selections.

5 Live With What Has Grown

Sometimes we don’t expect our annuals to grow so large. We might have wanted the container to look a bit differently, but there are times to roll with what we’ve got, right? You might have discovered what not to plant in your pots and boxes next year…but you might have found just the annual for placing among your perennials in the flower garden. Gardening is always an adventure, and we’re always called upon to be flexible.

I planted this container in 2021, not expecting that the plants would completely overwhelm the metal obelisk, not to mention the pot itself. Everything grew mulch larger than I expected. This was a situation when I just shook my head and said, “Okay…I won’t do that again.”
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