Beating the heat

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Gaillardia 'Red Sun'                                                  Terra Nova Nurseries

Hot enough for you? Temperatures are sizzling and our enthusiasm for fussing in the garden is wilting. With summer trending hotter, it’s more important than ever to choose plants that can take the heat.

Some garden favorite varieties are notorious for packing it in when summer simmers. Violas and pansies, pinks and lobelias will often shut down until things cool off. Even tomatoes will drop their flowers when temperatures hit the 90s – a situation that corrects itself after the heat wave passes.

It’s a good idea to choose low-care plants that tolerate heat and drought since you can’t always water as frequently as you should. Besides, you might want to get away for a long weekend without having every blessed green thing you own frying to a crisp.

With water a precious and often expensive resource, drought-tolerant plants cut down on irrigation demands. You probably already know plants that promptly wilt without enough moisture – impatiens are a prime example. You can quickly come to recognize less thirsty plants as well.

Many have fleshy, succulent leaves that store moisture like a cactus. Thick-leafed sedum and portulaca are two examples. Others have a waxy coating on their leaves or are prickly, like cactus and yucca. Narrow leaves and silver, gray or bluish foliage also signal heat and drought tolerance – think lavender. And of course, plants from southern climates, including zinnias and tropical lantanas, have evolved to bask in hot sunshine.

Drought-tolerant plants can hold their own through hot, dry spells – but only if you get them off to a good start. Newly transplanted specimens need regular watering to help establish the deep roots that will later range far in search of moisture.

Water the right way, slowly and deeply, to encourage roots to grow down into cooler soil depths. Light sprinkling will only encourage to roots to remain near the surface, where they are subject to drying out when rain and irrigation fails. Mulching beds after planting also helps keep the soil a little damper and cooler, and is a wise investment.

Yucca 'Color Guard'                       Terra Nova Nurseries

Many flowering plants qualify as good candidates for low-maintenance, heat tolerant gardens. Here are an even dozen to try:     

  • Armeria – Perennial. Tufts of grassy, evergreen foliage form a low, spreading mat (6 – 12 inches). Pink, white or red flowers resemble cottage pinks. Salt tolerant. Also known as sea thrift or sea pinks.
  • Coreopsis – Perennial and annual types. Profuse daisylike blooms are produced for 12 weeks or more on wiry-stemmed plants 18 – 36 inches tall. Prune back every few weeks to promote continued flowering.
  • Gaillardia – Annual and perennial types, also known as blanket flower. Brilliant daisy-style flowers borne all summer on 15 – 18 inch plants. Salt tolerant. Water only when very dry and don’t fertilize.
  • Gaura - Marginally hardly perennial. Airy, see-through plants bear abundant flowers on wiry stems. Pink types will not self-sow like white varieties. Likes winter protection (mulch or snow cover). 
  • Heliopsis – Perennial sunflower. Multi-branched plant 2 – 5 feet tall produces bright yellow flowers for as long as 12 weeks blooming late in the season.   
  • Kniphofia – Marginally hardy perennial from South Africa. Grassy foliage and spikes of bottle brush flowers in hot colors reach 2 – 4 feet. Also known as torch lily or red hot poker. Mulch to protect from winter cold.
  • Lantana – Tropical plant grown as an annual. Little “bouquets” of tiny flowers are followed by dark berries. Thrives on benign neglect. Sprawling plants to 2 feet make good container subjects.
  • Lavender – Fragrant perennial herb. Blooms profusely in June and may repeat if trimmed back. Requires good drainage. Varieties ‘Hidcote’ and ‘Munstead’ are among the hardiest. 18 – 24 inch plants.
  • Portulaca – Tender perennial grown as an annual. Low mats (4 – 8 inches) of succulent foliage produce satiny flowers all season. Also known as moss rose.
  • Sedum – Perennial. Many varieties, but the most useful are late-blooming upright sedums. Succulent foliage 18 – 24 inches tall supports heads of tiny flowers attractive to butterflies. Pinch back in July if plants become floppy. Also known as stonecrop.
  • Strawflower – Annual botanically known as Bracteantha bracteata.  Everlasting flowers are popular in dried arrangements. Most grow 12 – 24 inches tall.
  • Yucca – Perennial. Tough sword-like leaves produce a large spike of long-lasting, fragrant white flowers in summer. The leaves, 2-3 feet tall, are tipped with sharp spines; plants should be carefully sited.

Plant sources:

All of the plants mentioned, produced by Proven Winners and Terra Nova Nurseries,  should be available in local garden centers. To find one nearby that carries Proven Winners selections, see the retail finder at provenwinners.com. For Terra Nova selections, locate retailers and mail order sources under “How to Order”at terranovanurseries.com.