One of the new projects this fall/winter has been to replace the packed basalt gravel in the steps running up the back rock garden with concrete.
The reason why is all that hard packed gravel (4-6 inches of it) accumulates a lot of debris (wood mulch, branches, needles, cones, and weed seeds) that is hard to clean out.
While it doesn’t look too bad this time of year when everything is all dark and wet, once things dry out in summer, those bits of twigs and mulch dry out and look messy mixed in with all the gravel. Not to mention that the moles haven’t had any problem pushing their tunnels up through this, mixing a bunch of soil and even more weed seeds into everything.
Thus began the long slog through online videos and various websites trying to find out how to embed crushed basalt into concrete. The idea was to achieve the same look as I had initially with packed basalt rock, but also something that would be easier to clean – maybe with a broom instead of a noisy leaf blower. I watched a lot of videos about creating exposed aggregate using concrete, but I don’t like the look of the round pebbles that are in the concrete mix. I’ve been trying various ways of mixing clean basalt gravel into the concrete and then washing that afterwards to expose the basalt. Fail. Most of the gravel doesn’t stick nicely (bottom step) and pops right out, so I tried a different concrete mix (third step up from bottom).
That new mix, although cheaper, had even more round pebbles and the basalt gravel didn’t mix in well at all. So, back to the original mix (below). Not the cheapest, but it is less than $4 per bag and seems to have the least amount of pebbles.
Mixing the basalt gravel into the wet concrete wasn’t working, so I decided to try pushing the gravel into the wet concrete immediately after it had been poured. First, I picked out a bunch of larger gravel, then washed and dried it. Next, I poured concrete into an excavated step, then hand placed each piece of gravel, gouging it down into the hardening mixture.
I had to move fairly quickly after pouring, because as the concrete started setting, it became harder and harder to embed the basalt. I also found that the edges hardened faster than the middle, so I had to work around that outer edge first, and then work my way inwards. There was no way to photograph this process. It had to move fast and my hands (gloved) were covered with concrete by this point. Lastly, I smeared the top of the gravel with some black concrete dye.
And then it started to pour rain, so I had to cover the project until it had hardened some more.
Later that evening, about 7 hours later, I washed and brushed off the dye and top layer of concrete. This is what I ended up with.
It isn’t as black as I wanted. I really wanted a completely black gravel surface, but it was the best I could do. And, by then, I had two steps that didn’t match. Out they came.
I’ve since replaced the first and third step. The numerous frosts that have followed prevented me from making progress on the rest.
That bottom step didn’t go quite as smoothly and it doesn’t match the second step as much as I would like. The concrete didn’t set nicely and some of it came out during the washing process. I ended up patching it (poorly) in a few spots. I am hoping in 100 years, it won’t be as noticeable. I don’t want to take it out and try again.
I’m a little frustrated by the project, because it doesn’t look as professional as I would like. I see what others have in their gardens and I would like to have the same quality of hardscaping. But, that takes a significant amount of investment that we would rather spend elsewhere at the moment. So, rustic it is. Which, I guess, sort of fits the style that we have going anyway. I keep telling myself that it is better than the steep, brown lawn that it replaced and I have learned a lot by doing this project.
In other news, I planted a Gunnera manicata along our creek. That’s the large-leaved plant to the right of the creekbed below. It’s since disappeared for the winter. With the upcoming cold weather (into the upper teens at night), I guess I had better get out there and cover it with a good layer of leaf mulch. We also need to turn on the heater in the water shed so that our pipes don’t freeze. Rain has been sparse this December compared to last year.
You might remember that in early October that we were thinking of planting a Gunnera after we saw the giant specimen at Port Defiance Zoo (here). We decided not to plant one based on how late it was in the season. But, then, suddenly there was a free one at a blogger’s event in October. Loree, over at the danger garden, was tired of battling raccoons in her water garden and her Gunnera needed a new home. Well, here it is. Hopefully, it makes it. It sure would look pretty cool next to the creek.
Elsewhere in the garden, I planted some Colletia spinosissima that I rooted earlier this year.
I washed the potting media off of the roots, hoping that this might reduce the chances for root rot over the winter. While doing that, I noticed these white nodules on the roots. Hmm…
Could Colettia be a nitrogen-fixing plant? A quick look online indicated that yep, it is! Not only that, but I found out that Colettia is in the buckthorn family, Rhamnacaea, which also includes other genera with nitrogen-fixing capabilities, such as our native Ceanothus species. Hard to believe that the two are related given how different they look. Find out more about Colettia from the Heronswood blog (here). Now, I want to dig up one of our cascara buckthorns (Frangula purshiana) and see if those have root nodules as well.
I’m afraid not much else has been happening in the garden. Have been feeling lazy and we are both recovering from Covid-19. Very glad for vaccines and the anti-viral medications that help shorten the blah time. Hard to believe it’s been almost three years since that virus first arrived. Time to go outside a put some plants under protection for the coming cold snap.
I’m sorry COVID caught up with you but kudos for taking on some tougher projects even when the weather upped the challenge quotient. I’m sure you’ll appreciate the new steps as you use them and soon forget your concerns with them. I still have a stairway of concrete blocks leading down our back slope, installed in the early days by my husband. They’re not elegant but, when I remember how many times I fell on my back side before they were there, I appreciate them.
You are right, of course. This is the slope I slipped down many years ago while mowing the lawn and almost slid under the running mower. I vowed then that it was going to be replaced with a garden. This IS much, much better.
COVID came to our house too, but just Andrew, I somehow avoided it. I love your steps! I complete understand the desire for a uniform (darker) finish but I think what you came up with is spectacular. What a lot of work. Fingers crossed for the gunnera…
Thanks! I just shoveled a good thirty pounds of wet, sodden leaves over the Gunnera, so hopefully it will make it.