The sweltering humidity of summer has settled in around us, making outdoor chores a little harder to get accomplished. The prolonged heat can take a toll on our gardens, but it doesn’t necessarily have to stress our plants. With a little well-timed work and proactive choices, our gardens can beat the heat of summer.
Summer annuals are especially susceptible to these hot temperatures and the unforgiving sun. Often planted in patio containers, hanging baskets or simply dropped into urns, annuals are at the mercy of our water hose. But while they can easily show signs of stress, many annuals actually thrive in these conditions, hitting their stride mid-summer.
We should always be cognizant of how to make our annuals perform their best. These plants were meant to live for one season, bloom their hearts out for about six months and then die. Keep that in mind when you notice them languishing a bit this time of year. All they need is a little love.
To keep your annuals performing at their peak, consider the following — water, food, pruning, mulch and pests. Addressing these needs of your annuals can go a long way in perpetuating their blooms.
Water is perhaps the most important focus, with timing being the key. There is no use to water in the hottest part of the day, as most of the moisture will transpire before the plant has time to properly absorb it. Water your annual containers and in-ground plants in the coolest parts of the day, at sunrise or sunset. This ensures that water is reaching the roots and properly benefiting the plants.
Mike Shouse, the manager at Shouse Nursery in Winston-Salem, offered a lot of tips about watering and ways to beat the heat with summer plantings.
“If your plants are wilting — well, there are three different kinds of wilt,” Shouse said. “There’s heat wilt, water wilt and too much water wilt.”
Heat wilt is when a plant wilts because of the heat, not because it is dry. You see this a lot with big leaf hydrangeas in the hottest part of the day. The plant may not necessarily need water, as the foliage is just reacting to the heat.
Water wilt is when a plant wilts because it needs water. The soil is dry and pulled away from the sides of the container. After it is watered, the plant will perk back up quickly.
“Too much water wilt” is when a plant wilts because it is staying too wet. The soil is soggy and wet to the touch. The plants may recover if left to dry out, although it’s sometimes hard to reverse unless they’re re-potted.
“You really need to check the plant before you go and just dump water on it,” Shouse said. “It’s easier to bring a plant back that’s dehydrated, than one that has drowned.”
Regular fertilizer is also crucial to keeping annuals going strong. A combination of slow-release and liquid fertilizers are important to continual bloom. Shouse recommends using granular Osmocote (applied every 3 to 4 months) in conjunction with liquid fertilizer every 7 to 10 days. A 20-20-20 liquid fertilizer is good for bloom and liquid fish emulsion is good for ferns and foliage plants.
July is the time to start giving annuals a bit of a haircut. And by haircut, I mean a little pruning off the top. Upright annuals such as salvia and coleus can benefit from pinching if they start to get too tall. This will help the plant get a little bushier and wider. Spreading annuals like wave petunias need to be cut back to help encourage more bloom.
“Petunias and million bells will start to stretch this time of year,” Shouse said. “So it’s good to go in and cut them back about a third or half.”
Mulch goes hand in hand with watering. A thick layer of mulch is extremely helpful in hot summer weather, locking in valuable moisture to the soil, and keeping weeds at bay, as well.
While there aren’t a ton of pests that plague flowering annuals, there are a few to watch out for during the heat of summer. Japanese beetles are rampant right now, as well as slugs and snails. I’ve been handpicking Japanese beetles off my zinnias this past week. Shouse also warned about the healthy appetite of deer during summer, which are perhaps the biggest pest of all in some of our gardens.
“Remember to re-apply deer repellents this time of year. A lot of the real tender growth in the woods has hardened off. Your landscape plants and flowers that you’re pushing growth on is the tender growth for deer right now.”
When we brought home our flowering plants in the spring, we were cognizant of color, design and placement. We took the time to plant them accordingly and dote over them for weeks. Just be sure not to abandon your beautiful annuals when the weather gets hot.
“I know the fun is gone in gardening when it’s 90 degrees,” Shouse said. “But you still have to get out there and work with the plants to be successful with them.”