Category Archives: Drought

The Plant Lover’s Guide to Salvias (Book Review)

By:  Mary Jane Parker, Master Gardener

If you care deeply about natural gardening and attracting bees, insects and hummingbirds to your garden, then salvias should be one of your go-to plants. They have wonderful flowers and fragrant leaves and for me, they bloom almost all summer.

In this very readable book, The Plant Lover’s Guide to Salvias, John Whittlesey outlines designing with salvia plants in different climate zones. We learn that salvias are generally hot climate plants and many have low water requirements but some of the perennial ones can be treated as annuals in our climate. Some are rated for zones close to ours and will survive here as perennials. I have had Salvia glutinosa growing here for many years and the book rates that one only a US zone 6a. Culinary sage (Salvia officinalis) has overwintered for me also for a number of years.

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The author next goes through and discusses 150 species and exceptional hybrids, their country of origin and specific cultural practices for each and any notable characteristics such as a strong hummingbird attractor.

Finally, he discusses general cultural techniques and then provides a listing of sources for plants and seed. After having read the book and descriptions of different salvia species, I have ended up with a two-page list of interesting species I wish to try.

The Peterborough Horticultural Society has this book available in their lending library or you can purchase from Timber Press.

Where’s the Rain? How to Deal with Drought Conditions in Your Gardens

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.ONDrought_zpsal2mmbjn

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

Water Wisely

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.20180716_133136

Harvest Water

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 20180716_132548

Reduce Stressors

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.

Make Priority

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.

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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.fresh-2386786_640

Use Mulch

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.

Water Well

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.

Weed Management

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 20150822_185728

Dealing with Drought in the Garden

By Mary-Jane Pilgrim, Master Gardener

Plants are composed of anywhere from 50-90 percent water. When they suffer from the heat, it’s because of an insufficient amount of water being available to them. Drooping, seemingly lifeless leaves are a sign that a plant does not have enough water and is unable to take in carbon dioxide from the air through tiny, open pores on the underside of the leaves and make food.

When plants wilt from lack of sufficient water, they stop growing, stop producing and will die if their cells are not replenished with water.

Plant Selection

The best way to deal with drought is through plant selection. Grow plants that don’t ask for much!

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Choose plants that are drought resistant and can handle the heat in the first place, rather than struggling with the more sensitive types. Some suggestions are: ornamental grasses, salvia, sedums, cacti. Also native plants such as black-eyed susan, liatris, purple coneflower, coreopsis, lavender. Some non-native plants such as daylilies, hellebore, barrenwort/epimedium also all tolerate the heat well.

Watering

The best way to get moisture to the plants is to apply water at ground level with drip irrigation or via soaker hose, and the best time to do this is in the morning. The idea is to give the plants an infrequent but deep soaking. Water that seeps deep into the soil will help plants develop a deep root structure, which helps them survive prolonged periods without rain. The morning is the coolest time of the day, and there is less evaporation while temperatures are relatively cool than later in the day when the temperature is at or near its peak. The second best time is right at dark or just before dark.irrigation-2402568_640 (1)

Using sprinklers is not as optimal because a significant amount of water is lost due to evaporation from the leaves into the air before the leaves can absorb the water.  However, for extensive garden beds, it may be the only available choice!

For patio container plants, consider adding water gels to the potting mix. The gels absorb water and release it slowly to the plant roots, reducing the number of times the plants will need to be watered. Another option for patio containers is a self-watering pot. These types of containers have a water reservoir from which water is absorbed up into the pot and to the root zone. Like the gels, these specialized containers will reduce the need for frequency of watering.

Mulching

Another way gardeners can help their plants survive excessive heat and drought is to mulch their garden beds. The mulch will help reduce evaporation, insulate plant roots from the high temperatures and reduce or eliminate weeds, which compete with desirable plants for water and nutrients. When choosing mulch, use only biodegradable materials that decay over time. Two to three inches of mulch should be plenty for the growing season. Don’t put mulch up against trees because it can cause the trunk to rot. Also, mice and other vermin may create nests in the mulch and chew on the tree’s bark.

IMG_2320Shredded leaves are also an excellent choice, but they break down faster than wood mulch and may harbor seeds like maple keys. However, earthworms love shredded leaves and will make the soil more friable and fertile with their castings. If leaves are hard and fibrous, leave them in place to decay. Oak and other tough leaves should be shredded and allowed to decay a bit before placing on the garden. Soils topped with shredded leaves will soon be crumbly and easy to plant.

Weed-free straw is good mulch and is often used in vegetable gardens. It packs down and hold weeds at bay. Make sure to use straw (grain stalks) instead of hay (dried grass) to prevent seeds from germinating.

There are many other tips / tricks about gardening during drought but the key message is that “you don’t have to stop gardening due to drought. Simply change the way that you garden to adapt to the conditions.”