Cedar growth progress in 4 months

I wasn't sure how well my cedars had been growing until I came across a picture I'd taken earlier in the year when they were first planted. I didn't notice that they had actually grown quite substantially, as you can see in the "before" and "after" photos below.

The main reason I am posting these is that I couldn't find any such "progress" information when I was planning to plant this hedge, and there wasn't much out there to correlate planting technique with results.

And, first of all, I should say that when I first planted these cedars I was worried that they wouldn't make it. The spring heated up very quickly and we had some midsummer-like days within weeks of my planting. The trees looked visibly stressed and were flagging. I watered them deeply every 2-3 days during that period (I watered them 5 or 6 times in total since planting). Luckily, it was followed by a few weeks of cooler weather with regular rain. I have not watered them since.

Of course, there is still a winter to get through and still some uncertainty there.

But, here was what I did:

1. Dug a trench 4 feet wide and 1 foot deep, about 25 feet long. The existing ground was a mix of sand and limestone that was originally a base for an above-ground pool that I removed a number of years ago (it came with the house). So, I dug down to the soil underneath and also loosened that soil up with a garden fork.
2. Re-filled the trench with about 50% original "soil" and 50% new soil. The original soil was, as above, a mixture of sand and limestone chips. The new soil was a mixture of black garden soil, peat moss, and relatively small amounts of manure compost. My reasoning was that it would be very difficult to get rid of the sand/lime elsewhere in the garden, and that the black soil was very dense so could do with some loosening up via the sand/lime.
3. Added bone meal to the soil. Supposed to be good for root growth. I scattered it on the surface from a container that claimed to cover the area I needed and mixed it in with a garden fork.
4. Raked the surface flat. Not much to say about this.
5. Planted the cedars. I dug holes big enough for the potted cedars, with their centres about 2 feet apart. I tapped the soil away from the outer roots on each rootball before planting to loosen them up a bit (not sure if this is good or bad, to be honest), planted the trees, and filled the holes back in.
6. Starter fertilizer. I used a large watering can (9L) to apply water-soluble starter fertilizer. I used one full watering can per 2 trees.
7. Applied cedar mulch to the surface. I covered the soil surface with cedar mulch and distributed it evenly.

So, that's about it. We have had rain now and again (approx. twice every 3 weeks) and I haven't watered them other than what I mentioned above.

Today, I fertilized them with evergreen fertilizer for the first time since planting. "Advice" says I should have done it two months ago, but I don't like fertilizing things that aren't healthy because it can send them over the edge.

They seem to be doing well.