Mark Cullen: Beating the Heat

From Mark Cullen’s website:

If we do hit a short dry spell you may have garden plants that are wilting before your eyes. Some plants speak to us by drooping their leaves like a child who drags their knuckles on the kitchen floor, pouting for another cookie. Plants pout too. My rudebeckia and hydrangeas pout all of the time when it is hot and dry. Like a responsible parent, I don’t always pay attention. Put another way, I don’t choose to ignore them, I just don’t respond to them in a panic.

When you do water your garden do it between sun set and sun rise as much of the water that passes through your lawn sprinkler mid day is lost to evaporation. Water deeply. Apply H2O using a slow-mo device. I made this word up to describe the wide variety of great products that are on the market designed to slowly eek water to the root zone of plants. These are designed to be economical [as they save you water] and effective [as they move water to the root zone of plants, where it is needed]. Some of the slo-mo products include:

Weeping hoses. A hose with perforations in it that allows water to seep out slowly, not in a stream but more like a sponge that oozes water when it is full. Weeping hoses are made of either a tough synthetic fabric or recycled rubber. Both work best when they are buried under 4 to 6 cm. of bark mulch. I prefer the fabric ones as they last longer under the extraordinary hose pressure that I have at my place.

Heart Breaker. This is a Canadian designed water sprinkler that pulverizes the water into a mist and delivers it low, in a circular pattern and without a ‘hallow’ effect [where a portion of the ground beneath the water being applied is missed, creating a doughnut of dryness surrounded by wet]. Look for the Mark’s Choice line up at Home Hardware.

In-ground watering systems. Watch out for these as they can waste more water than a leaky faucet. If you own one, I recommend that you turn off the timer, unless it is one of the new ‘smart timers’ that knows when it is raining and the ground is already wet. One of my pet peeves is to see lawn sprinklers blasting away while the rain is pouring down. This happens in industrial parks all of the time. Ugggh. “If I was mayor of this city….!”

Turn on your in-ground lawn and garden sprinklers when the ground is dry, not until. And, I repeat, turn your lawn watering system off during a drought. It just does not make sense to try to keep a lawn active when it wants to sleep.


Forgive me for saying this once before, but it is important to know [and most people don’t] that all plants need oxygen at their root zone. When the soil around their roots dries out, the spaces between soil particles are filled with air [oxygen] and the roots are allowed to breath. This is a very good thing. Odd as it may sound more plants are killed by overwatering than underwatering. I have learned this based on more than a few years of retail gardening. I use rain-barrel water on all of my container plants and I think that their performance demonstrates the benefits very well.

Watering Trees

Oddly enough, Janet MacKay, Executive Director of LEAF here in Toronto tells me that the biggest challenge they have when they plant a tree for someone is to get them to water it regularly. So let’s define ‘regularly’. For a newly planted tree this means several gallons of water once a week, poured onto the root zone slowly enough that the water is absorbed by the soil around the new tree. This is why we create a crater of soil around the base of a newly planted tree and then mulch it with finely ground up bark mulch, which acts as a great insulator from the drying effects of the sun. You apply water to a new tree weekly for the first year, once every 2 weeks for the second year and once a month in the 3rd year and then the tree is on its own, until a drought comes along when you will water it deeply once again.

Which Plants?
There are many plants that are suitable for harsh, dry conditions. Of the many thousand perennials available, the sempervivums and sedums are extraordinary survivors in hot sun. Make that ‘thrivers’! Once they have been pampered with regular watering while getting established after planting, you can enjoy the summer off.

Many popular evergreens like mugo pine, junipers, taxus [yews] and cedars enjoy a dry spell from time to time. That is why we use so many of them in foundation plantings under the eave and soffit of our houses where rain seldom, if ever, falls.

Annuals that thrive on very little water include the brilliantly colourful portulaca [which grows between the patio slabs in my yard all on their own], dwarf zinnias, gazania, Cape Daisy, English ivy, spider plant, asparagus fern and good old-fashioned Boston fern.

When planting in containers I advise that you put a Water Wick bag right at the root zone of each plant. Put it in water until it has absorbed 400 times its weight and is nice and fat. Place it in the bottom of the hole where it will make direct contact with the roots. As your plants require moisture they will pull from the Water Wick and when you water your plants the bag fills up with water for a new charge. They are all natural [mostly sea kelp and corn starch] so no worries where the environment and kids are concerned.

Wacky weather patterns aside, do your garden and yourself a favour by watering smartly and only when (and where) absolutely necessary.

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