Stay Cool and Dig On. Ideas for Planting During Summer Heat.

Find planting inspiration and beat the summer heat at a top-rated SoCal garden center.

Written by Alicia R.

Maybe you’ve put away your garden gloves in favor of lounging on the patio. Admiring flowerbeds while sipping iced tea is pleasant during the heat of mid- to late summer.  But if you don’t feel inclined to recline, and you find it sweeter to hold a trowel than a tumbler of summer brew, take heart.

Don’t let anyone tell you this is the wrong time of season to plant. Many annual flowers, perennials, and vegetables tolerate heat, and some thrive in it.  But that doesn’t mean you should tuck them into the soil at peak of day and heat or expect a new, drought-resistant transplant to get by with weekly watering.

How to Make Informed Choices

Arming yourself with plant lists from trusted sources — such as the Los Angeles County branch of the University of California Cooperative Extension — can help in making wise selections for planting at different seasons.

Experts at garden centers are another good source of information about what to plant at varying seasons and how to help plants survive stresses such as extreme heat. If you click on the “About Us” menu link on the Green Thumb Nursery homepage, it will lead you to a list of experts at each of our five stores.

We have some tips for you about good choices and care for annuals, perennials, herbs, and vegetables that don’t mind getting started when temperatures are high.

Hot Weather Growing Tips

Here are some basic rules of thumb to follow when planting during the hottest part of the growing season:

  • Don’t confuse heat resistance with tolerance of being planted during heat. Some species do better when planted during cooler temperatures.
  • No matter how tough they are, heat-resilient plants should be transplanted at the coolest times of day, such as early morning and evening.
  • Water early in the morning or late afternoon when temperatures cool and foliage still has time to dry. Overnight dampness can cause problems like powdery mildew.
  • Depending on local heat and planting location, even low-water annuals may need daily watering until well established. Their roots are short and have to drink within about the first few inches of soil.
  • Although perennials eventually will be able to tap moisture deep in soil, their roots are also short when first planted. As they get established, which may take a few weeks, water at least every other day.
  • Overwatering generally kills more plants than underwatering.
  • Cut back on quantity of fertilizer but not frequency of application during extreme heat. Rapid uptake of nutrients during heat can lead to fertilizer burn.
  • Apply mulch to cool soil and conserve moisture. But don’t place it at the base of plants, because that can cause rot. This is especially true for extremely drought-resistant plants.
  • Many full-sun plants thrive with a bit of shade when getting established. Techniques for providing temporary shade doesn’t have to be expensive. Here’s one idea for making tiny sun umbrellas out of sticks and cardboard. And here’s a Los Angeles Times article on summer gardening that links to a video about constructing larger structures out of plastic piping and shade cloth.

Selections for Hot Weather Planting

Looking online, you’ll find a broad selection of edibles and ornamentals that can handle planting during summer heat. Here are some of the links we like:

University of California Cooperative Extension, Los Angeles County. Click on “Spring & Summer Gardening Basics” for an overview of Southern California gardening, including a long list of choices for August planting.

University of California Cooperative Extension, Santa Barbara County. Scroll down to “July/August” for plant suggestions and cultivation tips.

Sunset magazine. One of the top suggestions here is bearded iris (Iris germanica), which blooms in spring and early summer,  but is perfect to plant now. Iris is easy to plant and maintain (sidebar below).

Please remember that Green Thumb Garden Centers may not have all the plants these sources mention and that the selections we suggest may vary in availability from one of our centers to another. However, we’ll do our best to help you get what you need. Here are some good choices for planting now:


Alyssum, calendula, cosmos, impatiens, marigolds, zinnias


Angelonia (great in containers), bearded iris, camellias, and chrysanthemums


Basil, dill, lavender, parsley, rosemary, sage


Broccoli and close relatives such as brussels sprouts, cabbage, cauliflower, collard greens, kale, and mustard greens

Answers to Your Questions

If you would like more information about gardening during summer and other seasons or about any of the plants and products at Green Thumb, please contact us online or call any of of our centers. Green Thumb has what you need, including compost, fertilizers, mulch, top soil and garden tools.


Iris is a tough beauty queen. It withstands conditions including drought, winter freezes, and triple-digit summer heat yet maintains elegant, upright blades year-round.  In late spring and early summer, it produces delicate looking, ruffled flowers in a rainbow of colors.

The American Iris Society offers an illustrated tutorial about how to separate and plant bearded iris.  Roots sprout from their plump tubers, called rhizomes, which should barely be covered with soil. Clipping the blades of an iris into a six-inch fan helps to minimize the amount of foliage the rhizomes need to feed during initial growth.

The Society recommends planting from July through September.


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