When the heat of summer hits, gardeners aren’t the only ones drooping due to scorching temperatures and high humidity—perennial gardens often look tired, too.
With a little planning and effort, though, your garden will remain lush and lovely throughout sweltering summer conditions.
Just like us, plants get extra thirsty when temperatures rise. Make sure to water your perennial garden regularly. Most plants need about an inch of water per week—especially if they’re new additions to your garden. Add a rain gauge to your garden to see if you need to supplement Mother Nature’s efforts. When you water, give your perennials a deep drink rather than a shallow sprinkle to encourage strong root systems.
Even drought-tolerant plants need supplemental water during the first year in your garden so that they develop well. When you design your garden beds, take into consideration your perennials’ watering needs, and group plants according to the amount of water they require. Eventually, drought-tolerant plants will need less supplemental watering than those perennials that thrive in moist soils. By placing your plants according to their watering requirements, you’ll save water—and effort—once they’re well-established.
Hopefully, when you planted your perennial garden in the pleasant, cool spring or fall, you added a layer of mulch around your plants. If not, check the weather forecast for a day when the temperatures aren’t too extreme and plan a mulch party in the garden. Mulch not only helps retain moisture in the soil, which keeps your perennials hydrated, it also smothers weeds and prevents them from competing with your plants for water, sunlight, and nutrients. Add a thick layer of newspaper or cardboard to cover weeds or weed seeds around your plants, drench the paper with water to help keep it in place, then add mulch on top, which will hide the paper weed barrier.
Mulch also adds aesthetic appeal to the garden, making it look polished and professional. If you choose a natural mulch, like double ground hardwood or pine needles, the mulch also enriches the soil with organic components as it breaks down. Mulch helps amend heavy clay or sandy soils, creating rich garden beds perfect for more perennials!
Have your perennials put on a beautiful show in the garden this summer—and now look tired from the effort? Many perennials just needs a little TLC to create a second wave of color. Deadheading—the act of cutting faded flowers off the plants—often initiates a second round of blooms for many perennials, like hardy Geranium ‘Blushing Turtle’. Deadheading prevents plants from setting seeds, which signals to the plant that it’s time to stop flowering. Instead, snipping spent flowers encourages additional flower production, plus it tidies the garden by removing brown, droopy, unattractive stems.
Some flowers, like tickseed, can be individually deadheaded down to the next emerging bud. Others, like perennial geraniums, often benefit from an overall shearing of spent blooms, as they produce masses of flowers that would take ages to deadhead singularly. Choose a cool summer evening for deadheading chores. Your garden will look refreshed and tidy the next morning, and soon you’ll see new blooms on many of your favorite perennials.
Many perennials, particularly those grown in containers, benefit from a nutritional boost after deadheading. If you’ve planted your garden in rich soil filled with organic matter, your plants may not need additional fertilizer. In fact, too much fertilizer on heat-stressed plants can actually cause damage.
However, if your garden beds lack rich soil, or you’ve planted perennials in containers, your flowers will benefit from feeding. Container gardens need supplemental fertilizer, as nutrients leach from the soil with each watering. If you’re pampering new plants in your garden, choose a multi-purpose fertilizer and follow the directions on the label. If you’re hoping to encourage a second flush of blooms, choose a bloom booster fertilizer.
More is not better with fertilizer. Avoid damaging plants by using only the recommended amounts of fertilizer for your perennials and water well after application.
Many perennials in your garden may grow beautifully—until they suddenly topple over and stems snap during a summer thunderstorm. Provide adequate supports for top-heavy plants so you can continue to enjoy beautiful blooms without breakage.
New cultivars of common plants, like Achillea millefolium ‘Pomegranate’, require no staking. Instead, they’re bred with sturdy stems that withstand strong winds and rains without the need for support. Look for interesting, beneficial new varieties of your old-time favorites for the same beauty with less work in the garden.
With summer’s heat and humidity, many plants suffer from pests and diseases. Spend time in your garden daily so that you’ll spot the first signs of problems—and address problems quickly before your plants suffer. (Check here to help you identify common diseases.)
Powdery mildew, for instance, pops up in many gardens during the summer, particularly on common varieties of phlox, lilacs, and roses. At the first sign of powdery mildew, remove infected plant parts—do not compost them. Treat the plants with a fungicide designed to combat powdery mildew. Look for a fungicide with sulfur or copper in the ingredients.
An ounce of prevention is worth a pound of cure, and air circulation around susceptible plants helps prevent the fungal disease, as does staking tall plants to keep them off the damp ground. Clean up and remove fall leaves and plant debris to prevent diseases from lurking in gardens.
Along the lines of prevention, shop for perennial varieties that offer disease resistance. Coreopsis Creme Brulee, for instance, withstands harsh summers without succumbing to powdery mildew, as does Rosa Blushing Knock Out®. Choosing disease-resistant varieties when planting your perennial garden eases your garden maintenance efforts during hot summer months.
With a bit of effort, your perennials will continue to thrive and add beauty to your garden throughout the dog days of summer. After all, you want to spend time enjoying your lovely garden, especially during summer—and preferably with a cool drink in hand!
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