Springing into Action!

(Originally posted May 2, 2022)

Hello?!? Is anybody out there? Remember me? I am not offended if you don’t. It’s been quite a while since my last post. As much as I love writing about gardens, this is a side project for me; I do it strictly for fun and sometimes the fun things get put on hold when life gets busy. With that said, I am back and still planning on writing, so if you are willing to continue following my blog, then I am thrilled to have you along for the ride!

It’s hard to believe we are at the start of another growing season. Yay! Spring is here!

Spring. It’s an aptly named season when you really think about it: new life is ‘spring’ing forth from the earth after a long winter slumber, the sun is putting an extra ‘spring’ in our step as we gleefully skip along while the sun’s rays kiss our vitamin D deficient bodies, and we all ‘spring’ into gardening action at the first hint of a warm day. (At what other time of year does 10 degrees Celsius feel balmy??)

Forsythia spp.- a sure sign of spring.

Garage/shed doors are thrown open; gloves, hand tools and rakes come out (Ug. Did I really put those away in that condition?) and we get to work. Our desire to usher out winter and welcome spring is all consuming. With all that pent-up gardening enthusiasm we often get overly zealous with our spring tasks, so it is easy to get ahead of ourselves... which leads me to two main gardening mistakes that we tend to make in early spring:

1. Cleaning up the garden too soon

2. Mulching too soon

Lets look at each of these in turn…

Premature Garden Clean-up

So the equinox has come and gone, warmer weather has made an appearance… oh wait… now it’s gone… now it’s back again… and now it’s snowing?!? Ah yes, spring is an indecisive season. For this reason, it is best to refrain from cleaning out the yard on those first few warm days because severe weather can follow soon after. All the leaves on the beds, and standing herbaceous perennial foliage, can buffer garden plants (and soils) from harsh temperature swings and wild weather. Additionally, all the old flower stalks, perennial stems, and leaves in the garden are valuable overwintering sites for beneficial insects. Leaving everything in place for a little longer allows these beneficial organisms to emerge, enabling them to play a valuable role within the garden ecosystem in the months ahead.

Despite the benefits of all the ‘dead stuff’ in the garden, if you feel you must clean up a little, focus on areas where leaves have piled up over the winter months and make sure these leaf piles are not smothering evergreen foliage or perennials below. I usually do this ‘preliminary leaf clean-up’ within the first two weeks of April and then do a more thorough tidy-up (which includes cutting back herbaceous perennials) sometime between the middle to the end of April.

April snow is often cursed but not overly not unusual in these parts. It’s one of the reasons we need to temper our enthusiasm and hold off on spring clean-up until later in the month.

Mulching too Soon

No question about it, mulch on a garden looks great. (With the exception of red mulch…just don’t do it. Seriously.) Aside from aesthetics, mulch is valuable in many other ways but it’s useful properties make it more of a garden liability when it is applied too early in the season.

For example, mulch has an uncanny ability to prevent the evaporation of water from the soil. This is fantastic during the dog days of summer when rainfall can be scarce, but during the spring when rain is in abundance, we are often dealing with overly saturated soils. Depending on your soil texture, it can take a fair amount of time for soil moisture levels to decrease (clay soils take much longer to dry out than sandy soils). Putting mulch on saturated soil will prolong the length of time it takes for garden soil to dry out. In the meantime, some plants can suffer in the waterlogged conditions and some may rot away.

Mulch is also amazing at blocking sunlight. It is the main reason why it is able to suppress weeds- a thick layer of mulch blocks the light that plants need to grow, and that weed seeds need to germinate. Now take that same mulch and put it over top of perennials just starting to emerge, and you’ve got yourself a problem. I see this issue quite often on properties where landscape crews (who do not know the placement of garden plants that have yet to ‘wake up’) mulch too early in the season and inadvertently cover up (and sometimes smother) garden plants. Whoops.

A Hosta mulched-over by a landscape crew. Luckily this one had already emerged and was freed from the thick mulch blanket. Remember- mulch does not get put over top of plants, it goes around them! It’s hard to apply it properly if you can’t see the plants.

Another benefit of mulch is it’s ability to moderate soil temperatures. This is great for preventing freeze/thaw events during the winter (which can be detrimental to plants) however, if a thick layer of mulch is applied too early in the spring, it can slow the warming up of garden soils- which can negatively impact plant growth.

Finally, mulching should occur after amendment/fertilizer applications are complete (if this is necessary based on soil tests). Mulching before amendments have been applied essentially closes the window to applying amendments and fertilizers directly to the soil where it is needed. Fertilizing early is not an option because plants need to be actively growing to make use of the applied nutrients. If they can’t, the nutrients may be washed out of the soil before they even serve a purpose and nutrient loss can have negative effects within the surrounding environment. This is overly simplified and highly dependent on what is actually getting applied to the garden, but I think you get my point: amendments first, mulch next, but not too early!

As you can see, mulching too soon can be pretty detrimental to a garden. In my area, I generally do not start mulching gardens until the end of May. In some cases I will wait even longer- for instance if I have annuals to get into the ground. For me, the annual planting frenzy kicks-off the third week of May and lasts for a few weeks. It is much easier to apply mulch around annuals after they have been tucked into the garden, rather than try to plant them into a mulched garden bed (which requires the mulch to be pushed out of the way in order to access the actual garden soil for planting… definitely not an efficient way to plant!)

It is much easier to apply mulch after annuals are planted rather than have to dig through mulch to find soil to plant into.

And there you have it! A couple common spring gardening mistakes that I am sure we have all been guilty of at one point or another. So what’s the take home message in all of this? Well, if you feel ‘behind’ in your garden chores- don’t worry! You are most likely not as behind as you think; best case scenario, you are right on schedule! It’s far too early in the season to stress out about falling behind in gardening tasks. Enjoy the ‘spring wake-up’ at a more leisurely pace… your garden (not to mention your body) will thank you.

Wishing you a happy spring! It’s great to be back in the gardens :)

Sanguinaria canadensis (Bloodroot). It’s springtime in our woodlands!

Scilla Sect. Chionodoxa (glory-of-the-snow). A sea of blue is a spring sight to behold!

Soil pH- it's quite basic (or acidic), really

(Originally posted: June 1, 2021)

It’s been a flashy time of year in my neck-of-the-woods. For weeks, the floral fireworks ignited by our trees and shrubs have been creating quite the show in a colourful progression... Witchhazels! Maples! Forsythias! Cherries! Magnolias! Serviceberries! Flowering Pears!

…and…

Rhododendrons!

Floral fireworks of spring.

It is this time of year, when I longingly look at the blooms of the Rhodos. My feet then get ichy to ‘put the pedal to the metal’ and zip out to the garden centre to get a few (it’s best to buy in 3s, right!?) of my own.

Now I should say that kids are amazing at distracting one from the task at hand, so impulse purchases such as this have greatly decreased in recent years. This also affords me the time to let common sense prevail and I am then able to remind myself that these plants are simply not the right fit for my yard. Why? For me, the root problem is soil pH.

How I long for one of these in my garden! Alas it is not meant to be!

Let’s backtrack.

All plants have their preferences when it comes to growing conditions. Some like sun, some prefer shade; some like ample moisture, while others thrive in dry conditions. There are some plants that prefer humus rich soils while others perform poorly in these conditions. Generally, we factor-in these growing preferences when selecting plants for our gardens. To a certain extent, we can control these conditions- by situating plants in various areas of our yard that have the lighting/moisture conditions suitable to the plant at hand.

Two plants with very different preferences in growing conditions. Butterfly weed (Asclepias tuberosa) on the left that prefers sunny, dry conditions on sandy soil while ‘All Gold’ Japanese forest grass (Hakonachloa macra ‘All Gold’) shown on the right, prefers partial shade and deep rich soil.

There is one growing preference that is VERY easy to overlook, or even forget about entirely, but it can often be the key to a particular plant’s success or failure in a garden. Furthermore, it is a soil attribute that we have very little control over and essentially no power to permanently change. That attribute is soil pH.

Don’t worry. I am not going to get into any in depth chemistry lessons here. Essentially pH is a measurement (from 0-14) of how acidic or basic a solution is. A pH of 7 is neutral; anything greater than 7 is alkaline/basic (such as baking soda which has a pH of 8); a pH of less than 7 is acidic (such as lemon juice with a pH between 2-3). The optimal soil pH range for most (but not all) plants is between 6-7. Nutrient availability to plants is linked to soil pH and it is in this ‘optimal pH range’ that the nutrients necessary for plant growth can be found in their soluble forms (in ideal amounts) and therefore available for the plants to take in. Outside of this range, various nutrients can become ‘locked up’ in insoluble forms that the plants cannot access and nutrient deficiencies can result. On the flip-side, at certain pH levels, some elements can become ‘too available’ to plants- to the point where they become phytotoxic.

So what does all this mean for ‘us gardeners’? KNOW YOUR pH! A simple test kit can be purchased at your local garden centre. Alternatively, you can send soil samples off for testing at a laboratory. The reports from such tests are really useful as they generally include measurements of soil nutrient and organic matter levels. This can indicate whether or not amendments are required, and what amendments would be needed to optimize your soil for plant growth.

So- let’s go back to my plant lust example: the Rhododendron. These beauties are considered acid-loving plants- a special club whose membership also includes: blueberries (Vaccinium), mountain laurels (Kalmia latifolia), Japanese pieris (Pieris japonica), pin oak (Quercus palustris) and the list goes on. These plants prefer to grow in soils ranging in pH from 4.5 to 6. If soil pH is too high, these plants will exhibit chlorosis (a sign of iron and/or manganese deficiency- two elements that become more ‘locked-up’ at higher pH levels).

A hydrangea with chlorotic leaves

…but I have slightly basic soil. What are my options?

Generally, soil pH is determined by what lies beneath- the parent material. Since pH is essentially guided by the foundation from which the soil was formed, it means that pH is not exactly an attribute that one can permanently change by sprinkling a few pellets or powder on the ground! The overlying pH tendency of the soil will always prevail. Temporary changes to pH can be accomplished through the routine addition of amendments. For example elemental sulfur or aluminum sulfate can be used to acidify the soil while lime can be used to make a soil more alkaline, but this will become a yearly task to add to the gardening ‘to do’ list.

When it comes to soil, I am not really interested in trying to fight my conditions. So in this case I fall back on the mantra that we should all chant as we walk through the temptations that line the aisles of the garden centres:

”Right plant, right place”.

We're all in this together.

(Originally posted: May 11, 2021)

Sick of this phrase yet? I know it’s starting to wear on me too, but as inhabitants of a single beautiful planet that seems to get smaller and smaller with each passing year, we are in a lot of things together… changes in climate, waiting for rocket pieces to fall to earth, and visits from aliens… not aliens from outer space (although given the context, this would be applicable too), I am referring to earthly alien species.

An alien species is a species that has been introduced to an area outside of it’s natural range. Now it is important to note that an alien species is not necessarily a bad thing. In fact many of our cherished landscape plants are alien species that have come to us from the far reaches of the globe, brought together in our gardens in the name of horticulture.

Now that’s a LOT of aliens! Many of these beauties look like they come from another planet; they are certainly not from around here! Growing together in southern Ontario, they can be found on the property of a fellow landscape gardener who happens to have a passion for the rare and unusual.

Alien species become a problem however, when they are invasive- that is they cause ecological or economical harm in their new environment. Unfortunately we know alien invasive pests all too well. They are introduced (either by accident or intentionally) and wreak havoc on species that are near and dear to our hearts: Dutch elm disease (Ophiostoma ulmi) virtually eliminating elms from our landscape, emerald ash borer (Agrilus planipennis) decimating our ash trees, European gypsy moth (Lymantria dispar dispar) defoliating the giants that grow among us, Japanese beetles (Popillia japonica) obliterating our showiest of summer flowers and feeding on the roots of our plants…. phew! Need I go on? And this is just the tip of the iceberg!

The all too familiar sights of some common alien invasive pests. Clockwise from top left: a spongy moth (Lymantria dispar dispar) egg mass (that can contain up to 1000 eggs!), crown die-back on an ash tree associated with the feeding of emerald ash borer (Agrilus planipennis) within the tree, and Japanese beetles (Popillia japonica) caught in a compromising position…

With the constant movement of people and products across our globe, the introduction of invasive pests is a problem that is not going to go away any time soon and unfortunately the landscape industry in Ontario is monitoring a new pest- the box tree moth (Cydalima perspectalis)- an insect that was first detected in Etobicoke in the summer of 2018. This little pest is capable of severely defoliating a boxwood hedge in one growing season. Yikes! Not great news considering the fact that boxwood is a popular and widely planted shrub in the southern Ontario landscape. (For readers outside of the GTA in Ontario, my apologies! While I try to keep my information relevant to a wider audience, this is one topic that is ‘close to home’ that I feel I need to post! Besides, this may someday become your problem too! If you are already dealing with box tree moth in your country…thanks for sharing.)

I am not going to get into the nitty gritty of the box tree moth here, but if you want to know more about this pest and it’s biology, check out this article written by Jen Llewellyn (Ontario Ministry of Agriculture, Food and Rural Affairs Nursery and Landscape Specialist) and posted on the Landscape Ontario Website. It contains great information about the pest and contains fantastic photos too! You can also check out this handy dandy IDENTIFICATION CARD as a ‘Cole’s Notes’ reference source. Finally, Landscape Ontario has also put out a helpful FLYER with more information including photos of box tree moth damage and signs to watch for.

Now before you start feeling helpless and depressed by the seemingly bleak future of our boxwoods, there is actually good news… YOU CAN HELP! Yes you!

Landscape Ontario is looking for volunteers to become ‘citizen scientists’ (that means you don’t actually need to be a scientist!), mainly in the Mississauga, Brampton, Vaughan, Richmond Hill, Markham and Scarborough areas, to monitor for box tree moths on their own properties. Monitoring helps with early detection and control of the pest. It also helps scientists learn more about the biology, behaviour, and population ecology of box tree moth as well as how quickly it is able to disperse across our Ontario landscape; all this information can ultimately guide ‘best management practices’ and/or regulatory actions aimed at controlling/containing the spread of this pest.

Volunteer home owners/citizen scientists with boxwood plants on their properties are needed in the areas located roughly along the purple line.

So what is involved in becoming a citizen scientist for box tree moth monitoring?

In general, citizen scientists would:

• Host and hang a box tree moth trap (it looks like a green milk carton) approximately 1 meter from the ground, within 20 feet of boxwood plants, from May to September 30th, 2021

• Open the trap on the same day each week and report the number of box tree moths found (including photos of the moths)

• Store a packaged pheromone lure in the freezer for later use (it would be unwrapped and placed in the trap in the middle of August to replace the 3-month lure initially loaded in the trap)

• Continue weekly monitoring until the end of September

So… if you are ready to be a scientist contact me and I will connect you to the appropriate person.

If you are not ready to make the commitment, be sure to monitor your boxwood plants for this new pest. While there are multiple signs to look for, larvae (and their associated feeding damage) can be found between mid-May and mid-June and again between mid-July and mid-August. Findings can be reported to www.inspection.gc.ca/pests

Happy scouting!