On Garden Microclimates

A microclimate is a local atmospheric zone where the climate differs from the surrounding area. Microclimates can have microclimates, which can have microclimates.

I live in the Beaches in Toronto, very close to Lake Ontario. This puts my yard in a microclimate caused by the lake – 6a surrounded by the 5b of the Greater Toronto Area. Being really, really close to the lake, and having a tiny yard sheltered by tall fences that gets quite a bit of western sun – my garden’s really more a 6b.

But even within the tiny confines of my yard, small micro-climates reveal themselves.  The photo below is of three identical hostas. All Royal Standard, all planted at the exact same time, in the exact same manner, last summer. All within 12 inches of each other.

Microclimate Hostas

You guys don’t match at all.

Hosta Number One broke the soil over three weeks ago, and is full and lush and lovely. Hosta Number Two broke the soil about five days ago, and is about two inches tall. Hosta Number Three finally showed its head three days ago and is about one inch tall.

The image below shows what’s around them (the Astilbe and Blood Grass in the photo don’t count – they’ve only been there a week or two.

Hosta Map

Hosta Map!

So – Hosta Number One sits out in front – unshaded by the apple tree, and getting a bit more of the hot afternoon sun before the shadow from the fence falls across it. It doesn’t seem like much of a difference – I’ve never measured the extra time that Hosta Number One spends in the sun, but I imagine it’s measured in minutes. Still – it made over three weeks’ difference to the hostas.  That puts them in completely different growing zones, despite being about one foot apart.

So, when exploring your yard for microclimates, realise that it’s not just a matter of front yard vs. back yard – little things can make big differences.

This is a very simple example – microclimates can be caused by many factors, including soil and drainage. I’ve included some links below to more information from wiser people than me.


More Perennial Planting

Japanese Blood Grass - Imperata cylindrica - Red Baron

Invasive eh? You jerk.

Up and out early to Sheridan Nurseries, and then back to plant:

I also threw around some seeds, for the hell of it, we’ll see what happens. I planted matching seeds next to my coneflowers, astilbe and rudbeckia – plus sunflowers, sweet peas, chinese lanterns, cosmos, bellflower and nasturtiums.

I bought the Wisteria, despite having one, because it actually has flower buds on it. I’m amazed by that, getting them to bloom here is/was rare, I’ve never managed, anyway. I think some types just WON’T bloom until they are 10+ years old.


I’m more than a little bit horrified to read at Wikipedia that the Japanese Blood Grass is one of the most noxious invasive weeds IN THE WORLD!  Further research has made me feel a little better – seems like our cold winters keep it spreading so slowly that it can’t take over.  But when you read that a plant is more invasive in the U.S. south than kudzu, you feel a little bit bad for planting it. I’ll keep a close eye on it. Apparently the real risk is that the fancy red will revert to wild green, then take off.

It’s interesting though, and you see how these species can take hold and keep hold. I’m an inexperienced gardener, and I went to my local, reputable, nursery, and I bought a plant that I liked the look of, with no notion that it could possibly be a risk.

So much for my nice, mostly native, bird, butterfly and bee garden…