To help your garden survive the heat, the best defense may be a good offense. Ultimately, you’ll want
to watch the weather and take preventive steps to help your plants survive extremely hot days.

Tom Kalinski, RE/MAX of Boulder

Tom Kalinski, RE/MAX of Boulder

The heat waves blanketing much of the U.S. hit Northern Colorado recently. Studies show that this hotter trend will stay with us in the future. According to NASA, global temperatures in 2022 were 1.6 degrees Fahrenheit above the average for NASA’s baseline period of 1951-1980. 

The intense heat has undeniable consequences for the environment, yards and gardens included. In fact, U.S. Department of Agriculture plant hardiness zones are shifting north at 13 miles per decade. Local plants are beginning to show signs of stress, which negatively impacts your enjoyment and reduces curb appeal – a critical factor when selling a home. According to the National Association of Realtors, houses with high curb appeal usually sell for an average of 7% more than similar homes without the same landscaping. 

To help your gardens survive this ultra-hot weather, here are some helpful tips from Bob Villa’s website on home maintenance and design

Mulch keeps the ground surrounding your plants moist and cool. Apply a two-to-three-inch thickness of shredded leaves, straw or wood chips, but keep it a few inches away from the bases of trees to prevent rot and disease. 

Shade your plants
Even “heat-loving plants” need sun protection when it’s sweltering. Shade cloth is easy to set up and can be placed over outdoor plantings. You can also use other plants as your source of shade. For example, delicate seedlings can be planted under tall plants or lush vegetation. Container plants can be moved out of the sun when the thermometer rises.

Regular watering early in the day
Hot weather makes plants extra thirsty and extreme heat doubles the trouble by making it difficult for plants to soak up water through their roots. The solution is to water deeply when it’s hot, soaking the base of the plant and avoiding spraying the leaves. Container plants need more water than those planted in the ground and are the first to wilt in the heat.

Avoid evaporation by watering early when the sun is still low in the sky. Consider installing drip irrigation systems or watering by hand. Your garden can be irrigated with a soaker hose lightly buried under mulch or soil. You can also install a digital hose timer to ensure regular watering even if you are not home.

Watch the weather
While morning is typically the best time to water, when scorching temperatures are in the forecast, you can consider watering the night before. Drip irrigation allows the water to slowly absorb into the ground, bringing your plants the most significant benefit. 

Don’t stress your plants
Regular gardening activities such as pruning, fertilizing and transplanting cause plant stress and should be avoided during a heat wave. 

Eliminate weeds
Weeds compete with your plants for water and other nutrients; plants don’t need additional stress in boiling temperatures. The best way to eliminate weeds is by pulling them rather than spraying them with pesticides, which has other negative environmental impacts. 

Plant according to your zone
Since our gardens live on the edge of heat tolerance, give them a fighting chance by planting varieties that best survive in our climate zone. Boulder Country and Northern Colorado east of the foothills is in climate zone 5, with a short growing season and a frost-free period from early June until early September. The best perennial plants for zone 5, or those that will survive more easily, especially in heat extremes, include asters, astilbe, bee balm, cannas, coneflowers, crocus, daffodils, delphiniums, hibiscus, hostas, hyacinths, irises, lilies, peonies, phlox, salvia, sedum, tulips and yarrow.

Stay in tune with your yard and garden and help maintain your home’s curb appeal by watching for signs of plant stress. The visual signals vary, with some leaves wilting, others cupping upward, and some drying out in response to heat. To help your garden survive the heat, the best defense may be a good offense. Ultimately, you’ll want to watch the weather and take preventive steps to help your plants survive extremely hot days. 

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By Tom Kalinski. Tom is the broker/owner of RE/MAX of Boulder. He has a 40-year background in commercial and residential real estate. For questions, email Tom at [email protected], call 303.441.5620 or visit