By Emma Murphy, Master Gardener
(top photo courtesy of the Missouri Botanical Gardens website; Dogwood (Cornus) wilting from water stress)
Just two years ago, the Peterborough area experienced Level 2 drought conditions. Local residents and businesses were encouraged to reduce their water use by 20 per cent daily and there were 11 days in August when daytime temperatures were higher than 30 degrees Celsius.
Drought conditions usually relate to sunny, dry conditions, combined with an extended period of very hot weather, and it looks like the summer of 2018 is shaping up to be very similar to 2016. “The watershed region received below normal precipitation amounts in June, and during the first two weeks of July precipitation has been 25% of normal.” said Dan Marinigh, Chief Administrative Officer for Otonabee Conservation.
So what can a gardener do to help their gardens survive (and even thrive) during dry or drought conditions?
In the Short Term
Just before or during drought conditions
Recognize the Signs of Stress
Plant dehydration symptoms include:
• Curling or rolling of leaves
• Slowed/no growth, undersized leaves
• Leaves, blossoms, or fruits drop prematurely
• Wilting, limp and droopy leaves
• Leaf scorch, yellowing and/or browning, death of leaf edges
• Dead or brown/dying extremities starting from the outer leaves inward
Avoid watering during the heat of the day when evaporation rates are highest. Water either very early in the morning or late in the evening, and adhere to any watering restrictions that may be in place. Try and keep water off flowers, as sunlight is magnified through water droplets and can damage delicate flowers. Depending on your garden, consider hand watering rather than using a hose or sprinkler. Hand watering using a watering can targets the water to the areas that really need it, keeping waste to a minimum.
Water harvesting is a great way to use water from your home’s roof and direct it onto the landscape, where the soil becomes your “holding tank.” The best example is using a water barrel – we have four of them in our garden and they are a great investment. You can also practice ‘passive’ water harvesting by creating depressions that fill with water from the roof runoff or formal rain gardens, both of which help with stormwater runoff issues. You can find out more about rain gardens here. Peterborough Greenup Rain Program
Skip the fertilizer or pruning live branches during drought conditions. No need to add to the plant stress! When soil moisture is low or temperatures are high, plants don’t benefit from fertilizer and without adequate water, fertilizer can burn your plants. Excessive pruning will stimulate new growth that will not be drought tolerant. However, it is good practice to deadhead flowers, as removing spent blooms before they have a chance to set seed saves energy for your plants.
Give priority to watering newly planted trees and shrubs during periods of drought. Young plants have not had sufficient time to establish deep root systems, and depend on surface water for survival. Do not let the root balls of newly planted trees and shrubs dry out completely or become too saturated.
Over the Long Term
Planning for Future Drought Conditions
Think About Plant Selection
Use appropriate plants, which are often marked as drought tolerant or resistant. Consider native plants, which generally adapt better, have lower water demands, and fewer pest problems. Group plants according to how much water they need. Ask your local garden centre or nursery staff which plants they recommend. Check out members of the local Peterborough Area Garden Route. Peterborough and Area Garden Route
Maintain Healthy Soils
Good soil is the foundation for good plant growth. Anything you can add to your native soil like compost or other organic matter will make it easier for roots to penetrate deeper, creating more expansive root systems that can seek out water and nutrients. The result? Healthier, more drought-resistant plants. Good soils are better able to absorb surface water runoff, minimize erosion, and access nutrients and sediments.
Mulch reduces evaporation, moderates soil temperature, and inhibits weed growth. It is estimated that three quarters of the rain falling on bare soil is lost to plants through evaporation and runoff. Both of these are reduced up to 90 percent by adequate mulch. Use compost, wood chips, bark nuggets, shredded bark mulch, shredded leaves, or any other organic material to cover the surface of the soil at least 5 cm deep.
Deep watering encourages roots to go deep down in the soil to where it is moist and a lot cooler. Water less frequently but for longer periods, so water reaches deep into soil. Good thorough watering promotes healthier plants. Also, water only when necessary, based on condition of the plant. Most plants will normally wilt in hot sun, and then recover when watered. Also, a dry surface is not always a sign of water need. The surface generally dries out first and is not a true indicator of what is going on down deep near the plant root. Make use of a hand trowel to check for moisture.
Weeds will compete with your plants for moisture and nutrients. Keep your gardens and areas beneath trees and shrubs weed free. Once the weeds are eradicated, apply mulch.
Consider Alternate Watering Methods
Investigate use of soaker hoses or other irrigation techniques using a timer, which keeps water on the soil and reduce losses by evaporation. Adjust watering frequency and amounts based on season, temperature, and amount of rainfall. Overhead watering uses more water and encourages fungal diseases.
Practice Water Conservation
Not just in your gardens. Water is our most valuable resource. Learn how to reduce water use throughout your house and gardens at this link.
Water Conservation Fact Sheet – Otonabee Conservation