Reading Sun and Shade Through the Day
This week is a homework week before it's anything else, and I'll warn you now: it takes patience. You can't fake this one. You actually have to watch your yard.
Every plant on my "belongs here" list has an opinion about sun, and that opinion is non-negotiable. Penstemon wants full sun and doesn't want to hear otherwise. Some of the shorter grasses will take part shade and sulk in deep shade. Put the wrong plant in the wrong light and it doesn't matter how good your soil is or how careful you are with water, it's just not going to thrive. It might survive a season out of spite. It won't do the thing you bought it to do.
So before you buy one single plant, you need to know what your yard actually gets, not what you assume it gets.
Why your assumption is probably wrong
Most people picture their yard the way they experience it, which is usually morning coffee and evening yard work. That's maybe two hours out of the daylight. It tells you almost nothing about noon, or 3pm when the sun's been baking a spot for six hours straight, or that corner by the fence you'd swear is shady only because you're never out there at 10am.
I've been wrong about my own yard more than once. That strip along the south fence I tore out for penstemon and rabbitbrush, years ago? I thought it got "some shade" from the neighbor's tree. Turns out that tree only shades it about forty minutes in late afternoon and the rest of the day it's getting hammered. Good thing, in that case, because that's exactly what those plants wanted. But I got lucky. I didn't actually know.
The method
Simple and a little boring, which is why people skip it and then wonder why their new plants look embarrassed by August.
Pick a Saturday you're home most of the day. Doesn't have to be a work day off, just a day you're around.
Every couple hours, walk your yard and write down what's in sun and what's in shade. I do 8am, 11am, 2pm, 5pm. Four checks is enough. You don't need to camp out there.
Note it by zone, not by exact square foot. "South fence, full sun all four checks." "Under the maple, shade until 11, then dappled." "East side by the driveway, sun until about 1, then shade the rest of the day." That's the level of detail you need.
Do this in the season you're planning to plant. Sun angles change a lot through the year. What you see in March is not what you'll get in July. If you're planning a fall planting, which, opinion time, is what I recommend for almost everything, do the walk in early fall so you're reading the light close to how it'll hit the ground when your plants are trying to establish.
That's it. Four notebook entries, four times a day, one Saturday. Maybe fifteen minutes total spread across the day, plus whatever you were already doing at home.
What counts as "full sun" here
Elevation matters for this too. We're up around 4,600 feet, the air's dry, and the sun here is more intense than what a lot of plant tags are written for, especially tags from big box stores that source their info from somewhere with more humidity and less UV. "Full sun" on a tag usually means six or more hours of direct sun. Up here that still holds, but our afternoon sun in July is a different animal than morning sun. Six hours of morning-into-early-afternoon sun behaves differently than six hours that's mostly 1pm to 7pm. Both count as "full sun" on paper. In practice the second one is rougher on a young plant.
So when you take notes, jot down which hours, not just how many.
Guessing versus hauling in fixes later
Why I care about you doing this properly instead of eyeballing it: a story that still embarrasses me a little.
A few years back I was hauling rock from the landscape yard for a project I hadn't planned well enough. I'd guessed how much I needed instead of measuring my beds properly, grabbed extra "just in case," loaded the truck bed way past what I should have, and blew a tire on the drive home. Wasn't a small thing either. I won't say exactly how much I had back there. Marian knows. She has opinions about it still.
The point isn't the tire. It's that I skipped the measuring step because I was in a hurry to get to the fun part, and it cost me a wasted afternoon, a tow situation, and a lecture I deserved. Reading your sun and shade properly is the same kind of unglamorous step. Skip it and you'll be back at the nursery in June buying replacement plants for the ones that cooked, or the ones that never got enough light to bloom. Do it now, it's boring, and it saves you real money and real disappointment later.
Before next time
Pick your Saturday this week and do the four-check walk. Notebook or just your phone, doesn't matter, just write it down instead of trusting your memory. We'll use this map of your yard next lesson when we start actually matching plants to spots.