The Case for Leaving the Leaves

There is a lot of talk in gardening circles, as well as in the wider media, about ‘leaving the leaves’, not raking or blowing them off our properties and sending them to be composted by regional facilities, but ‘leaving’ them.  But what does ‘leaving’ them actually mean? 

Best gardening cultural practices are constantly changing as we discover more about how our gardening behaviour affects our properties, local ecosystems, and the broader environment.  What is meant by gardening cultural practices?  Simply put, these are the ways we deal with plants, pests, soil, water, fertilizer, the insects and animals that visit, and live in, our gardens, and all of the individual aspects of gardening and considerations that go into the decisions we make about what we put into our gardens and how we care for our gardens.  So how does this affect the way we manage leaves?  Leaving leaves on our properties is beneficial in more ways than one. 

Nutrients and Minerals

Up to 80% of a tree’s nutrients and minerals end up in the leaves.  By leaving leaves to decompose on our properties we are allowing these nutrients and minerals to return to the soil.  Insects and microbes, such as bacteria and fungi, work to decompose the leaves, leaving a nutrient and mineral rich compost that can be left in, or added to, any garden bed.  Using this natural fertilizer is a way to limit, or even eliminate, the need for commercial fertilizers.

Resources

Leaving leaves on our own properties also reduces the resources used to cart the leaves away.  Whether it be with conventional garbage trucks that take bagged leaves to regional waste facilities to be made into compost, or by trucks with mounted vacuums that take loose leaves from the curbside directly to waste facilities, there are resources used to move these leaves that could be saved if we compost leaves on our own properties. 

‘Leaving’ the Leaves is Really a Misnomer

It’s not practical to simply leave the leaves where they fall.  On driveways and walkways, they become slippery hazards, and, if you have enough of them, leaving them as they are on a lawn will deprive the grass of sunlight and trap moisture, a guaranteed path to smothering and killing grass.

Leaves must be moved to areas where they can decompose without harm; to either garden beds or to designated composting areas.

Moving Leaves

Use a rake or a broom to move leaves around.   Don’t use leaf blowers if you can avoid it.  According to www.leafblowerguide.com, even a light-weight, cordless, electric leaf blower will blow up to 60 miles per hour (mph), or 96 kilometres per hour (kph), with the vast majority of the 250 leaf blowers they review blowing at a much greater speed than that, some blowing at over 225 mph (360 kph), more than twice the speed required to lift up and move a car.  Overwintering insects and small animals can not survive winds of these speeds. 

Leaf blowers can also be more polluting (by far) than the vehicles we drive.  See https://www.edmunds.com/about/press/leaf-blowers-emissions-dirtier-than-high-performance-pick-up-trucks-says-edmunds-insidelinecom.html for a detailed comparison of the emissions of two different vehicles and two different leaf blowers. 

Adding Whole Leaves to Garden Beds

With a little care, whole leaves can be added to garden beds.  Don’t completely cover any plants that don’t die back to the ground over the winter, such as hellebore, heuchera (coral bells), iberis sempervirens (candytuft), as well as low evergreen shrubs such as juniperus (junipers) and euonymus groundcovers.  Tucking the leaves around these plants, as well as shrubs and taller grasses, will help insulate their roots over the winter, keeping them at a more constant temperature and helping to prevent damage from freeze thaw cycles. 

Mulching as an Alternative to Leaving Leaves Whole

Whole leaves will blow around when they’re dry.  It’s impossible to control exactly where they land, and, as it takes up to one or two years for leaves to break down, they will still be there in the spring.  An alternative to leaving whole leaves in garden beds, and moving whole leaves from lawns and hard surfaces into garden beds, is to mulch the leaves first.  Mulched leaves are less likely to blow around, and will decompose sooner than whole leaves.

How to Mulch/Munch Leaves

‘Mulching’, like ‘leaving’ (as in ‘leaving’ the leaves), is a bit of a misnomer.  The act of cutting up the leaves is more like ‘munching’, while the act of putting the resulting leaves in garden beds is actually ‘mulching’. 

Munching the leaves is done with what is known as a mulching mower.  While traditional mowers have only one cutting surface on a straight blade, mulching mowers have several cutting surfaces on typically curved blades.  The curved blades help to throw leaves and grass clippings back up into the blades to be further cut into smaller bits.  (Mulching mower conversion kits can be purchased for some traditional mowers.)  Going over a pile of leaves several times with a mulching mower is recommended to cut as many leaves as possible. Be patient. This can be done directly on a lawn, or leaves can be raked onto a hard surface, like a driveway or sidewalk to be mowed there.  While it’s much easier to rake or sweep up cut up leaves from a hard surface, doing it on a lawn will result in the added benefit of leaving some of the smaller pieces of cut up leaves to decompose right there, adding nutrients and minerals back into the soil that will feed your grass.

Once leaves are cut up, they can then be moved into garden beds.  As with whole leaves, don’t completely cover plants or shrubs that retain their leaves/needles over the winter months.  While whole leaves can mat together making water management a challenge, cut up leaves will let water filter down into the soil, as well as allow air to circulate through.  And emerging plants will easily poke right through in the spring.  Leaving mulched leaves to further decompose over the summer months will further add nutrients and minerals back into the soil and may decrease the need for commercially purchased fertilizers and mulches.

The Case for Oak Leaves

Oak (querqus) and sycamore (platanus) leaves can be a challenge as they take a long time to break down.  Running over them with a mulching mower can be done, but the resulting mulch will take longer to decompose than other leaf mulches.  Because these leaves are so tough, they may dull the blades of mulching mowers more quickly than when mowers are used to mulch other types of leaves.  Some people go so far as to have a second mower to use just for the purpose of mulching leaves. 

On the plus side of the leaves slow to decompose, many commercially purchased bark mulches also take a long time to break down, so if a long-lasting mulch is your goal, then using cut up oak leaves as a mulch may be something to try.

Too Many Leaves

If you have mature trees dropping loads of leaves, you may simply have too many leaves to deal with on your own property.  Shipping excess leaves as yard waste to be composted by the regional waste facility is nothing to be ashamed of.  Our residential properties are not natural forests and can not always accommodate the amount of leaves our trees drop.  There is nothing ‘all or none’ about gardening and dealing with leaves is no exception; any part of ‘leaving the leaves’ that we do will result in keeping the nutrients and minerals produced by our trees on our properties, helping to protect perennials and shrubs from harmful freeze-thaw cycles by using whole or cut up leaves as mulch, and reducing the resources required to move leaves from our properties.

Attracting Pollinators to Your Gardens

A Bit of the Backstory

There has been lots of talk in the last few years about declining bee and monarch butterfly populations.  While birds, bats and other insects and small mammals contribute to the process, bees are responsible for most of the pollinating that happens to the plants that not only provide us with a colourful display of flowers, but also the plants that provide us with much of what we humans consume.  

Monarchs, for their part, do help to pollinate some flowers too, but, more than that, they have become the darling of our butterfly world.  Their life cycle, the other worldly gold spots on the monarch chrysalis, and the phenomenal annual migration to Mexico and back have become a rite of passage in the learning of many Ontario kids.  In all stages of their life cycle they bring beauty and wonder to our gardens.

Why are Some of Our Pollinators in Decline?

Neonicotinoids (‘neonics’), a class of insecticides used to coat crop seeds to prevent pest damage, have been found to be the culprit for much of the bee losses in North America.  Some countries in Europe have now banned the use of neonics, and, for its part, Ontario introduced legislation in 2015 to limit the use of neonics here.  But the damage has been done and bee populations are significantly down.  So, in an effort to rejuvenate the bee population, gardeners, environmental organizations, and community groups are making special efforts to grow flowers that bring back the bees.  Even General Mills, with their Cheerios promotion, are giving away free wildflower seeds.

While the decline in bee populations has been largely due to the use of these insecticides, the decline in the monarch butterfly population appears to be threefold; illegal logging of the fir trees where the monarchs overwinter in Mexico, climate change, and loss of milkweed habitats in southern Canada and the U.S.

So what can we do about threats to pollinators?  I think the most important thing we can do is to stay informed, as the known threats to bees and monarchs develop and evolve.   The issues affecting the health of our pollinators change rapidly.  Think about it, until recently OMAFRA, the Ontario Ministry of Agriculture, Farming and Rural Affairs, listed milkweed as a noxious weed and fines could be imposed for having milkweed on your property.  Now local governments support the planting of milkweed on private properties to encourage the growth of habitat for monarch butterflies.

So What to Plant?

You will hear, over and over again, plant native plants.  Why?  Because the pollinators that we are trying to attract have evolved over time to feed on native plants, and, in some cases, use these plants to lay eggs on.  It's all part of complex ecosystems that we shouldn't try to mess with.  Using monarchs as an example, they will only lay their eggs on milkweed.  Period.  There’s no tricking them into laying eggs on any other plant.  They just won’t.  While monarch butterflies will feed on many types of flowers, caterpillars need to feed on milkweed to grow and thrive. 

Bees, for their part, are generally attracted to blue, purple and yellow flowers, although they will feed on the nectar and pollen of other colours of flowers as well.

Here’s a short list of perennials, shrubs and trees that will bring bees and butterflies to your garden from spring right through until the first frost in the fall.  The botanical name is first, with a common name in parentheses afterward.

Achillea (yarrow)

Amelanchier (serviceberry)

Asclepias incarnata (swamp milkweed)

Asclepias syriaca (common milkweed)

Asclepias tuberosa (butterfly milkweed)

Asclepias verticillata (whorled milkweed)

Aster (aster)

Buddleia (butterfly bush)

Caryopteris (bluebeard)

Cercis (redbud)

Chelone (turtlehead)

Coreopsis (tickseed)

Echinacea (coneflower)

Eupotorium (Joe pye weed)

Hypericum (St. John’s wort)

Lonicera (honeysuckle)

Lupinus (lupin)

Malus (crabapple)

Monarda (beebalm)

Oenothera (evening primrose)

Penstemon (beardtongue)

Prunus virginiana (chokecherry)

Rudbeckia (black eyed Susan)

Sambucus (elderberry)

Sedum (stonecrop)

For an inexpensive hit of flowers you can try to grow many of these from seed, but I find it well worth the investment to buy plants already grown to a good size by local growers.   Most of the plants listed above are perennials, and the ones that aren't (milkweed and lupin specifically) you can let go to seed in your garden so that new plants will come up on their own in future years.

Bees and butterflies are also attracted to many annuals and herbs, including those listed below:

Annuals

Lobularia maritima (sweet alyssum)

Cosmos bipinnatus (cosmos)

Helianthus (sunflower)

Heliotrope

Lantana

Tagetes (marigolds)

Zinnia (zinnias)

Herbs

Tanacetum vulgare (tansy)

Anethum graveolens (dill)

Levisticum officinale (lovage)

Angelica, Angelica (angelica) 

Mentha (mint - in pots only!!!)

Coriandrum sativum (cilantro)

Agastache foeniculum (anise hyssop)

Origanum vulgare (oregano)

Tanacetum parthenium (feverfew)

Lavandula (lavender)

Thymus (thyme)

Foeniculum vulgare (fennel)

Petroselinum crispum (parsley)

Remember as well, vegetables and fruit trees are great attracters of pollinators, and will help to feed your family too!

Lawn Care in January

Something I thought I'd never talk about;  lawn care in January.  But here it is, an absolutely frigid January day and I'm thinking about lawns.  Why?  Because I had a client late last year who, due to circumstances beyond his control, didn't get his lawns raked in the fall.  The day I came to him in December was the same day a good accumulation of snow was forecast.  I starting clearing the leaves for him before the snow started, but couldn't get through everything before a low level blizzard came through and I found myself bagging more snow than leaves.  So we left it, hoping a January thaw would allow us the opportunity to get more of the leaves from the lawns.  And as the temperatures went above zero and much of the snow melted away earlier this week I returned to rake.  In January.  A first for me. 

There's so much information out there about lawn care; fertilizing, seeding, watering, mowing, but I don't think there's enough emphasis on raking.  It's important to rake and it's important to rake often in the fall before things freeze up.  When leaves sit on grass and settle in during warm and wet weather, they mat together and form clumps that smother anything trying to live underneath.  I learned this first hand years ago my then young son made a leaf fort on our front lawn.  He piled leaves from our neighbours' trees and made a long fort along the front.  I did rake, but not until November when the leaves from our Norway maple fell.  Much to my dismay all of the area under where the fort had been had turned yellow.  I hoped the grass would come back in the spring, but it didn't.  The leaves had deprived that huge patch of lawn of everything it needed to stay alive.

When people show me dead patches in their lawns in the spring they usually assume some unseen bug or disease is to blame, but more often than not it's that they've left leaves on their lawn the previous fall, leaves that settled in, matted and killed the grass underneath.  

So remember next fall, don't wait until all of the leaves on your trees have fallen before you rake.  Rake them up, or better yet, mulch them with your lawn mower, and then rake them up and put them in your garden beds.  The little bits will stay in the lawn to feed the soil and the bigger bits will insulate your garden beds and break down over the winter feeding the soil there.

Dealing with Drought

The summer of 2016 was one of the driest on record in southern Ontario.  This, after a winter of little precipitation, resulting in a trifling amount of snow melt. 

The effects of drought are seen immediately in some plants, while others struggle through with signs of stress coming much later.  Needy annuals in containers will show signs of stress first.  They wilt, leaves turn yellow and then brown, and flower production stops.  Sometimes they bounce back with a good watering, other times not.  They are our canary in the coalmine, revealing to us immediately their need for water.

Some perennials, too, will show signs of water stress quickly.  Phlox and ligularia will wilt, and the leaves of ostrich ferns and astilbe will dry out and turn brown.  Hydrangeas suffer, showing shrivelling leaves, and later, smaller flowers.    But unless we have these bell weather plants in our garden, showing us the effects of dry conditions, we forget about the big guys, our workhorse woody shrubs and trees, toughing it out, not revealing the stress they are under until much later.

This summer we saw leaves on trees turn brown in September, weeks before they would typically have shown their autumn colours.  We see small branches on shrubs and trees losing their leaves and dying, branches that are brown underneath their bark, indicating they’re dead and need to be removed.

We may see smaller buds on spring flowering shrubs, larger branches fail to leaf out next spring, and insects and disease moving in next summer.

Cedars, touched not only by drought, but by the relentless heat this summer, are showing yellow and brown. 

A general rule for watering trees during a drought is 1”-2” of water every week.  Putting out a flat bottomed container to catch water is a good way to measure how much your tree is getting. 

There are many factors that go into how much and how often you water.  Soil type and whether or not there’s grass under the tree canopy are two of the most important considerations.  Clay soil holds water more than sandy soil.  And trees with grass under their canopy will need more water than trees with bare earth or mulch underneath.  As always, the best time to water is early morning.

We’ve had two good days of rain this week.  Everything needs it.  But remember, the season of watering is not over.  Deciduous shrubs and trees will continue to need water until they drop their leaves.  Coniferous trees need water right up until the ground freezes. 

And remember next spring that if there’s little or no snow melt, trees and shrubs will need water as soon as the ground thaws, and will continue to need water right through the spring, summer and fall, whether from rain or from your favourite sprinkler or soaker hose.

It's the most wonderful time of the year

Sing it with me!  

Whether you're a gardener or not, spring is what we've all been craving after our long, horrible winter.  And it's here!!!

This spring has been cold in Oakville.  We've had the odd (very odd) day when it's almost warm enough to wear shorts, followed by snow flurries and freezing ice pellets.  Welcome to April.

But it's May now, and warm days are here!  Spring clean ups are one of the most rewarding things I do for people.  Taking out winter debris, raking, tilling, trimming, pruning, edging, mulching, and planting.  Wowza!  Things couldn't be any better in gardens.  It's a time for hope, optimism and tons of planning.

Three more weeks until we're out of the woods with respect to frost.  Be patient.  It's just around the corner.  In the meantime, if you have perennials, shrubs or trees in your garden plans for this year, now is a great time to plant.

Blooming now...

Tulipa tarda

Pasque flower

One determined onion

April Showers

Twenty to thirty millimetres of rain forecast for tonight.  It's April.  

Itching to Get Dirty

It happens every year.  The winter is long, memories of gardening are distant and vague, and the months of snow, ice and short days seem to go on.  And on.  And on.

And then March hits.  The light changes.  The snow begins to melt.  The temperature flirts with double digits (on the positive side).  We change to daylight savings time.  March break comes.

You get it.  We're ready!  Please, spring, show your warm side!  Let's see some green!  Let spring cleaning begin!

It's been slow to get going this year.  We still have stubborn snow piles in shadier spots where I live, and the temperatures have yet to encourage a good wander around the garden. But it's coming.  I just know it is.

So until we're there, stay warm, it's coming soon.  I promise.  And until then, I leave you with some eye candy from  a recent trip to Italy where spring is already in the air.

It's not over 'til the fat lady sings

You may know this phrase commonly associated with Yogi Berra and baseball, but it also very much applies to Canadian gardens.  

We all talk about "putting the garden to bed".  Night night.  All tucked in.  What my clients really mean when they say this to me is this:  Cut everything down and take it away!

But there's more to do to put a garden to bed than just cutting everything down and taking it away.

Preparing for the Ravages of Mother Nature

Remember last winter?  Ice storm?  Bunny damage?  Polar vortex?

Ice should be for Skating

There's not a whole lot we could have done to protect against the ice storm.  And if it happens again (please no) we will all be at Mother Nature's mercy.  But think about your trees and how they reacted to the weight of the ice.  There were lots of trees around that could have been saved if they had been properly pruned along the way.  It's a good reason to have an arborist come in to assess the health of your trees.  

Buffet Anyone?

Bunny damage was extensive last winter.  The only way to protect woody shrubs is to enclose them in chicken wire to at least 4' tall.  Use string or twist ties to attach the top of the chicken wire to the branches of each shrub and garden staples from  www.leevalley.com to fix the bottom of the chicken wire to the ground.  That way the bunnies won't be able to crawl underneath. Alternatively, hammer in a perimeter of bamboo or 1" x 1" wooden stakes and attach the chicken wire to the stakes.  It's a lot of work, but well worth the effort in protecting precious shrubs.

Never had I Heard this Term Before

And the cold...Polar Vortex.  Gawd forbid.  If this happens again, we're all moving to San Diego.  It was just too cold for some things last winter.  Roses, buddleia, caryopteris...the list goes on.  There's nothing to say you can't put mulch around the base of your plants before the super cold weather comes.  People have been doing it with roses for years.  Snow can be a great insulator, but if we don't get sufficient quantities plants just freeze.  Wait until we get the first real hard frost and mulch away.  

Now that's putting a garden to bed.  

I can hear the fat lady singing now.

Summer Annuals Be Gone

It's at exactly this time of year when many summer annuals start looking out of place.  The blooms are not as plentiful, the colours not quite right.  Pull them!  Pull them all!

Enter fall plantings.

Sage, Japanese blood grass, and a hen with a few of her chicks

You can go the traditional mum, aster, ornamental cabbage and kale route, or, try something different.  Think about other plant material that can provide colour and form and will stand up to the variable weather that is our fall.  Grasses, anemone, perennial herbs.  Look for perennial flowers you can use in your fall containers that can later be dug in to your garden.  Echinacea, gaura, gaillardia may all still be blooming well into September and October and can look fabulous in containers with complementary foliage.

Winning combinations:

• Any of the yellow or orange echinaceas with imperata (Japanese blood grass) and perennial sage
• Any purple heuchera with gaura
• Anemone with ornamental blue or purple cabbages

Go with different leaf textures and plant forms for optimal drama.

And for those of you that can't wait for Halloween, find yourself a funky pumpkin to lay at the feet of your creation.  And it doesn't have to be orange!  White, grey, peanut.  Be creative!  Have fun!