Don’t let the summer heat keep you from adding plants to your garden. Here are tips to make it work.
A misconception about gardening is you never should plant during summer when it is hot. Conventional wisdom says planting is best done in spring and fall, when the weather is cooler.
But this only applies when transplanting or dividing, which is digging up and moving all or part of a plant that already is established.
It is nearly impossible to dig up an established plant without destroying some of the roots. If you try to move the plant during the summer heat, when the plant is top-heavy with growth, the shock can be fatal.
As daily temperatures rise, you still can fill the empty spaces in your garden with potted perennials, annuals and shrubs. Any shock from transplanting is essentially eliminated because you did not dig up the plant.
Below are some planting tips for reducing heat stress.
Find the Right Spot
One of the great things about planting in summer is most plants are in their full flush of growth. This allows you to better visualize the total effect because you can see a plant’s form and the color of its foliage or flowers.
The added dimensional aspect aids landscaping choices.
Yet there are more than a plant’s good looks and your personal preference to consider when placing your plant.
Anytime a plant goes into the ground, you should match the plant’s growth habits to the garden site.
This is true in any season but especially in summer, when temperatures are more extreme.
A plant that prefers part shade, but tolerates full sun, has a better chance of surviving in full sun if it is planted in spring rather than summer. This gives the roots enough time to establish themselves before the summer heat.
When planted in full sun on a hot summer day, the plant might wilt before it has a chance to situate its roots. To plant in summer, give the plant what it prefers: a partly shady location.
When planting in a sunny location, another way to protect the plant is to provide temporary shade for the first week or two using a light-colored umbrella, shade cloth or other structure that serves the purpose.
A little preparation goes a long way to determining whether a plant thrives or fails.
When you plant can be just as important as how you plant. For best results, always plant on a cloudy day or in the cooler temperatures of the early evening. This minimizes weather-related plant stress.
Cloudy days or cooler evening temperatures mean less transpiration loss from the plant’s leaves.
Basic planting steps apply, regardless of the season you plant:
Dig a hole a little deeper and about twice as wide as the plant’s root ball.
After digging the hole, fill it with water and let it drain before putting in the plant. This helps ensure an easier transition for the plant.
Gently work the root ball loose with your hands or a garden fork.
Put the plant into position and backfill with good soil mixed with a little compost.
Tamp the soil to stabilize the plant and remove any air pockets, then water thoroughly.
After the Fact
Immediately after planting, give your plants an advantage over the summer heat by applying a 2- to 3-inch layer of organic mulch, such as compost, shredded leaves, cocoa bean hulls or bark dust. This helps conserve soil moisture and keep down weeds, which compete for water and nutrients, whether your soil is loamy, sandy or clay.
Water new plantings once or twice with a diluted solution of fish emulsion or liquid seaweed to help them settle quickly into their new environment.
During the first week or two, you might need to water daily or every other day, depending on the weather, soil type and the plant’s growing requirements. After that, it is important to keep the soil slightly moist until the plant becomes established in the garden. For most perennials and shrubs, that usually occurs after the first growing season.
The key is to water deeply and thoroughly to encourage a deeper root system.
It only takes a little extra attention and a few simple techniques to help new summer plantings thrive.
So go ahead and take advantage of summer plant sales and fill in those empty spaces in your yard. The result cannot be anything less than beautiful.
What to Plant
Just about anything growing in a container can be planted in summer, though some plants stand up to the summer heat better than others. Here are several tough contenders for summer planting.
Standout shrubs: Barberry, boxwood, bluebeard, chaste tree, clethra, cotoneaster, holly, honeysuckle, hydrangea, Japanese plum yew, juniper, rose, santolina and spiraea.
Persistent perennials: Japanese anemone, artemisia, aster, catmint, chrysanthemum, coreopsis, daylily, echinacea, geranium, goldenrod, helenium, liatris, ornamental grasses, phlox, plumbago, Russian sage, salvia, sedum, verbena, veronica and yarrow.
Late-color annuals: Celosia, chrysanthemums, coleus, cosmos, creeping zinnia, dusty miller, dwarf sunflowers, globe amaranth, impatiens, marigolds, nasturtiums, salvia, scaevola and zinnia.
Conquer and Divide
An easy way to find new plants for the empty spaces in your yard is to divide perennials that already exist in your garden.
September is a great time to dig in and divide plants such as asters, chrysanthemums, daylilies, iris, liatris, rudbeckias and ornamental grasses.
Divide and replant perennials with vigorous clumps, barren or dead centers, and those whose flowers have become smaller or less abundant.
The steps are basically the same, whether the plant grows from rhizomes, such as iris; has tuberous roots, such as daylilies; or are more fibrous, such as rudbeckia.
Dig up the plant on a cloudy day, keeping as much of the roots intact as possible. Remove any loose soil so you can see the crown and roots, then divide the plant into smaller clumps using a sharp spade or sturdy knife, discarding any dead centers to the compost pile.
Each division should have at least two to five vigorous shoots with ample roots attached. Cut back remaining foliage to half the plant’s height, then immediately replant the divided pieces into their new location.
Any extras can be planted in potting soil in large pots and later given as gifts to friends and family.