Allow plants to shelter, adapt as hot weather hits

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It’s the new normal. Climatic extremes are the reality of today’s gardening, and our sudden early heat is a prime example.

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We must now deal accordingly with what we are experiencing and adapt. The result has made changes to our overall plant choices and garden maintenance practices, so I thought a few points would be worthy of mention.

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This is the traditional weekend, especially in the Lower Mainland, to set out our heat-loving bedding plants, but we need to be a little more mindful of all our plantings, including our existing perennials, trees, shrubs, and tender outdoor summer tropical plants.

So many of the plants we set out now have come from warm greenhouses, and they must be acclimatized, or “hardened off,” before going directly out into hot sun and those still-cool evenings.

This process is simple; it just means leaving them outdoors in a protected area, out of the sun and wind, for at least a couple of days and nights. You would be surprised how this toughens them up to better withstand our more extreme weather.

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We must be far more diligent in proper soil preparation. The addition of good quality compost and organic matter to our gardens is essential to create more open, porous soil. The key to successful transplanting, and ultimately your plants’ tolerance to varied weather conditions, especially heat, depends upon soil with good moisture retention, but which drains well, too.

Nutrient is more important than ever. Whether you use organic or more traditional fertilizers, your plants need access to not only nitrogen, phosphorus and potassium, (N-P-K), but to micronutrients as well.

Lime also plays an important role. While most commercial potting soils are pH balanced (below seven is acidic and over seven is alkaline or basic), at the very least our gardens, especially in the Lower Mainland, usually benefit from a minimum spring application of Dolomite lime to raise the acidity of the soil to a pH range somewhere between five and eight. Tomatoes, particularly, will need that calcium later on to help prevent blossom end rot, which can spoil those ripening beauties.

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Proper watering is critical for the success of all our plants. Soft rain nozzles at the end of our hoses or water wands helps dramatically in the even distribution of water. Most of these nozzles have 400-1,000 tiny holes to soften the application of the water. Make sure you never have too much pressure when watering, just enough to do a thorough, deep watering without disturbing any roots. Try to keep water off the foliage and flowers, and water both ground beds and containers evenly, making sure the water goes deep into the soil to draw the roots down.

If you are able, always water in the morning when temperatures are on the rise so the plants can make the very best use of the moisture. Evening watering is sometimes all we can manage but remember that plants transpire a lot of this moisture away at night.

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Only water when your plants are on the dry side because too much moisture will simply saturate the soil, preventing oxygen from getting to the roots and resulting in root rot.

On hot days don’t be fooled when some plants wilt. They are responding to the intense heat but still may be in moist soil, so be sure to check before adding more water.

We water baskets and containers quite frequently, consequently leaching out much of the nutrient in the soil. Regular feeding, especially with a time-release fertilizer will keep your plants growing well.

The heat we’ve had this past week has also been hard on many of our existing plants. Hedging cedars, especially the older established ones, have such shallow root systems that they need a thorough deep watering at least once a week. We are seeing so many dead ones in our neighbourhoods, and it is simply the result of insufficient water to the roots.

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If you can take a fork and gently loosen the soil around the drip line of many of your plants, you’ll be able to add new organic matter. Sea Soil, with its kelp and fish meal, will make an almost immediate difference to the plant health.

An application of a slow-release high nitrogen fertilizer, along the drip line as well, will help all your trees and shrubs regain vigour. Again, when you do water, make sure it is enough to penetrate deeply rather than just surface watering to ensure the nutrient reaches down to the roots.

Drip or soaker hoses are by far the best and most efficient ways to water because all the water is going directly down to the roots so none of it is wasted. Hand watering plants, especially with a soft rain nozzle, is also better than sprinkling, since you are concentrating the flow directly to the roots and can make sure the water goes deep.

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After this past week’s heat wave, many broad-leafed plants as well as leafy plants like hydrangea macrophylla, may show some leaf burn. With proper watering they will recover, but you may have to remove some of the dead foliage.

Sun exposure from about 11 a.m. to 4 p.m., particularly when it’s extremely hot, can result in leaf burn on many plants.

What we learned from our 40 C summer heat a few years ago is that it is critical for our plants to have moisture before the heat of the day hits, so an early morning watering will make all the difference to the health of the plants. This is especially true on the south and west sides of buildings where plants are additionally subjected to reflected heat.

Mulching is something we all need to be thinking about. I prefer fir or hemlock bark mulch, because of its proven moisture retention qualities and the fact it can be worked into the soil any time to improve its porosity. Add at least three to four inches of mulch, making sure you extend it to the drip lines of your plants where the new roots are forming. You’ll find rhododendrons and azaleas really benefit from regular mulching.

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Our lawns are relevant and very valuable in our environment. Keeping them green will help cool homes and neighbourhoods, as well as provide us with oxygen. A weekly watering of one to two inches of water is all that’s needed, so most water restrictions will still allow you to maintain your grass. The addition of white or micro clover into our existing lawns will also help keep them green. Electric or battery powered mowers instead of gas-powered units are much more environmentally friendly, too.

I hope you all enjoy this long May weekend. As you plant those vegetables, annuals, perennials and colourful flowering shrubs in your gardens and on your patios, please keep our pollinators, birds and butterflies in mind. Providing them with a wildlife friendly habitat makes gardening a win all around.

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