Garden experts list weatherproof plants that save time, money

As you’re planning and planting your garden this year, you’ll want plants that can stand up to weather extremes. With record breaking heat waves and ongoing destruction from droughts and flooding, it looks like extreme weather conditions may be here to stay, at least in many parts of the world.

Some plants, however, refuse to be taken down by Mother Nature – you could call them the ‘ultimate fighters’ of the horticulture world. So for each of the following extreme weather conditions, garden pros list some gardening tips for extreme weather, with some of their go-to plants:

Saltwater flooding/salt damage

“Storms like Hurricane Isabel in 2003, Sandy in 2012 and numerous tidal-flooding northeasters have given me considerable hands-on experience with salt-tolerant plants,” said Chesapeake Bay, Virginia-based garden writer Kathy Hogan Van Mullekom.

Her favourites include Flower Carpet^® roses, native wax myrtle, salt bushes, ornamental grasses, gardenias and bulbs. She also recommends big-leaf hydrangeas, rugosa roses, India and yedda hawthorn, osmanthus, bald cypress, Japanese black pine, Eastern red cedar, Hollywood juniper, live oak, yaupon holly and salt cedar.

“The saving grace is most storms include rain, which naturally washes the plants and the soil around them, reducing the salinity in the ground,” said Van Mullekom.

When it comes to resisting the corrosive effects of salt spray, Van Mullekom recommends hydrangeas, rugosa roses, Sea Pinks (armeria maritime) and ornamental grasses. As for the ice-melting road salt used in colder areas, she says thick-leaved plants fare the best, but you should still rinse the ice and salt off any affected plant and saturate the surrounding soil with fresh water. 

Heat

If we keep having summers like last year’s, it’s important to find heat-resistant plants that hardly blink at extremely high temperatures. But remember, heat-resistant and drought-tolerant aren’t the same thing. Those that survive the heat in northern gardens include heucherellas, some heucheras, phlox, daylilies, ornamental grasses, amsonia, sedums, artemisia, and some groundcovers. You can ask a local garden centre or botanic garden which varieties do best in your area.

Jane Schwartz Gates, of Gates & Croft Horticultural Design in the desert/chaparral area of Santa Clarita, California, uses heat-tolerant favourites like Jerusalem sage, guara, Flower Carpet® roses, cosmos, Storm™ agapanthus and Festival™ Burgundy cordyline (known as Cordyline Red Fountain™ in the southern hemisphere). Storm, the only agapanthus to survive the Dallas Arboretum’s famous plant “trials by fire” in extreme heat, is also favoured as a firescaping plant – along with Festival Burgundy cordyline (Cordyline Red Fountain) – in hot, humid regions.

Drought

Making certain your beds are well mulched is essential to dealing with any drought conditions.  Organic mulches include softwood or hardwood chips, evergreen needles, straw, grass clippings, leaves, bark chips and even newspaper and cardboard. These mulches eventually decompose and can be incorporated into the soil. Inorganic mulches include rocks and stones, lava rocks, pulverized rubber and other man-made materials.  However, stones and rocks absorb the heat and can warm the soil more quickly in the spring, but they also hold the heat, which can be dangerous to plants during periods of high, dry heat. 

Van Mullekom vouches for the following drought-tolerant plants: milkweed, sedums, camellias (once established, if you live within their cold-hardy zones), nandinas, herbs, Verbena bonariensis, coneflowers, lantana, butterfly weed, euphorbia and ornamental grasses.

Year after year, Flower Carpet groundcover roses also get high marks for heat and drought tolerance from Tesselaar Plants’ home testers: “Even though we had temperatures of 113 degrees Fahrenheit (45 degrees Celsius) for several days this summer, and no rain, all I did was water them very well once a week, and they performed beautifully,” reported Carrie Glenn of Howe, Oklahoma.

Too wet/freshwater flooding

“Very few plants can tolerate standing water or soggy ground,” said Greg Frank, vice president of Ted Collins Tree and Landscape in precipitation-heavy Victor, NY (Zone 6a). “If the air pockets around soil particles are filled with water, the plant will suffocate.”

A full immersion while a plant is dormant shouldn’t hurt it, said Frank: “And once they’re growing in the spring, a 24- to 48-hour immersion won’t stress them that badly. But much more than that will stress and weaken the plant in a very short time.”

Frank said the following plants can tolerate “wet feet” (soil that’s mostly wet, even with a possible 24-hour period of standing water, but that still contains enough air pockets for roots to “breathe”):

• Trees: red maple, Juneberry (serviceberry), locust, Kentucky coffee tree, larch, magnolia, sycamore, red oak and willow.
• Shrubs: shrub dogwood (red or yellow twig and grey stem), summersweet, witch hazel, privet, bayberry and viburnum (arrowwood and cranberry).
• Groundcovers: vinca and ajuga.
• Perennials: hosta, astilbe, Japanese iris, liriope, bee balm, sedges and many ornamental grasses.

Jane Milliman, editor of New York’s Upstate Gardeners’ Journal, also likes her colourfully foliaged Tropicanna^® cannas, which she says are “amazing in their ability to grow quite literally with their roots in water.”

Cold/frost

Late spring and early autumn frosts are often disappointing to home gardeners.  One frost in late spring can quickly wipe out a garden or container filled tender perennials and annuals.  So, before planting, check with your local garden centre or extension service to learn when the approximate last spring frost date is for your area. To spare yourself disappointment, select flowering plants that are pretty tough in the face of inclement weather. Autumn-planted, spring-blooming bulbs (daffodils, tulips, crocus, etc.) definitely fall into that category. Columbine foliage will rebound from a freeze and make an attractive foil to the bulbs, while self-seeding pansies and violas and plants that wintered over from last year can take the frost.

In the autumn, the following plants will still look good after a frost (when the temperature dips below 36 degrees Fahrenheit / 2 degrees Celsius): Malva sylvestris (common mallow), heuchera (coral bells), Jacob’s ladder, and most roses including Flower Carpet roses, and hardy mums. Volcano™ phlox, a sturdy garden phlox that reblooms multiple times if deadheaded, also continues to bloom through a few early frosts.  After a hard freeze (temperatures below 28 degrees Fahrenheit / -2 degrees Celsius), you can often still count on dianthus, alyssum, pansies, colchicums, golden sedum and grey artemisia.  And as a bonus, many ornamental grasses turn gorgeous shades of gold, red and bronze after the first early frosts.

Natives, neighboUrs and the Net

When choosing extreme weather plants for your climate, said Van Mullekom, it also helps to “use a mix of plants native to your area, because they adapt to changing climate conditions.”  Look around your neighbourhood to see what works well where you are throughout the seasons. With the plethora of information available online, it’s easy to do your homework before investing in a plant.