The benefit of the drought

By some estimates, California is experiencing its most severe drought in more than a millennium. I get asked a lot about the drought-tolerant plant installation I created last year, and so I’ve done a little write-up in the hopes that it might inspire others in their water-conservation efforts.

I took advantage of the Los Angeles Department of Water and Power’s turf removal rebate, which offered $3.75 per square foot of turf replaced with water-friendly landscaping. Although the state funding for this program has mostly, er, dried up, a limited number of agencies including LADWP are offering rebates at the time of writing.

Once upon a time we had a lawn, but with the water shortage the cost of maintaining it was starting to weigh heavily – on the wallet, on the environment, and on the conscience. Following the bone-dry SoCal winter season 2014-15, it didn’t look too great. I decided it was time.

I applied for the rebate around March 2015 and stopped irrigating the lawn. It took about 3 months to get approval; here’s what it looked like after 3 months of no water:

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Horrible. This was my starting point.

Although there are other ways to kill off the remaining grass, I decided to rip it all out. I chose this option because the soil had become rock-hard, and I felt it could use some loosening and aerating before attempting to plant anything. So I started to dig…

I quickly found that our landscapers had done something a bit dodgy with the low-voltage cables feeding the outdoor lighting. Instead of burying them to the proper 18-inch depth, they had merely draped them on top of the soil and hidden them with the turf. My first task, then, was to bury these wires.

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As I continued loosening soil, I started to encounter the buried irrigation pipes. One of the requirements of the rebate program is that pop-up sprinklers used to water the lawn be removed, and optionally replaced with low-water outlets – microsprays or a drip system. I had planned to put in a drip system and wanted to make use of the existing irrigation pipes, so when I accidentally broke a couple, I needed to fix them. Which I did. Then I discovered the pipes I had fixed were part of an older irrigation system no longer connected. Nevermind, it was good practice. It also inspired me to make a map of the whole area showing all PVC pipes, electrical cables, drain pipes, water main and so on.

By this point, I was beginning to wish I hadn’t started:

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But, eventually, everything was nice and loose, and mapped-out, and buried again.

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I now had 1225 square feet of bare earth surrounded by wiggly edging, as my blank canvas. For me the hard part is knowing what to put there. To this end I had spent many months trying to gather ideas from the web and from local gardens, in an effort to decide what I liked and might be capable of emulating. I opted for a multi-texture approach, and planned to cover the area with a mix of wood-chip mulch and crushed rock in two or three colours.

Mulch. What an excellent word. Decorative mulch is available at many outlets, but plants really require a 2-3 inch layer, and the cost soon racks up if you’re trying to cover any significant area. But did you know that it’s often possible to obtain free mulch? It won’t look quite as pretty as the kind in the shops, but will perform the same functions – reducing evaporation, and decomposing to feed nutrients into the soil. The way to get it is through a tree-trimming company. They routinely generate tons of mulch on a daily basis, and some of them will drop it off at your house for free. Here’s the company I used:

http://www.greenleaftrees.com/free-wood-chips/

The only drawback – they couldn’t deliver anything less than a truck-load. So that’s what I got:

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Of course I had to get it off the road. 27 hours later, and 44 trips with a 60-gallon wheelie bin, I had moved it round the back of the house. At roughly 100 pounds per bin-load, that’s 2 tons of mulch, and needless to say, I was in pain for a while.

I also ordered about 3 tons of crushed rock and crushed red brick from a local supplier – Central Valley Builders Supply (http://www.cvbs.com/), which got delivered onto my driveway. Oh good, I thought, more shovelling.

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I capped off all the sprinkler risers. A tip here: to prevent leaks caused by mains water pressure, use a half-dozen turns of teflon tape on both threads of the riser, hand-tighten, wait a day, then hand-tighten again before burying. If you need to be able to remember where they are, for future use, mark their locations like I’ve done here with blue flags:

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I also had some nice flagstones just lying around, not really being featured, so I experimented with shaping them into a stepping-stone pathway. This immediately started giving some structure to the area.

Part of the plan was to create a border using the crushed red brick, which I began delineate using plastic edging:

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Now, the rebate program requires that a weed barrier (landscape fabric) be installed over the entire area. I can think of 3 reasons why this might be so – it traps more moisture by reducing evaporation, it eliminates the problem of weeds interfering with any new plants which are trying to establish themselves, and lastly a rather human reason – it makes homeowners a bit less inclined to re-install grass at a later date. The weed barrier can be seen going in here under the red brick:

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Boulders make a nice enhancement. The one on the left was repurposed from another part of the garden; the one on the right I actually dug up when loosening the soil! This soil has a lot of clay, which becomes compacted over time, some of it eventually forming these crumbly bouldery chunks. I found a couple of other nice rocks on countryside walks.

The landscape fabric must be fastened with staples. The rather flimsy 4″ ones from the local garden centre I found to be a bit too insubstantial for the job, so I ordered some chunkier 6″ ones from a pet supplies seller on eBay. I suppose they’re for fastening dog fences but they work perfectly here, and are very cost effective when ordered in bulk – about 5c per staple.

With the border complete I used ropes to experiment with shapes for the other rock areas:

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After finalising a shape, I would mark it onto the soil and use the line as a guide for laying the edging. I found I got quite good at doing the curves after a while, although to certain degree the edging tends to fall into something akin to natural spline, due to constraints imposed by the soil pushing on the buried section.

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After giving this area the weed barrier treatment, some tan coloured stones went down:

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I received plenty of assistance at every stage from furry friends.

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The juxtaposition of mulch and stones provided the textural contrast I was aiming for:

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The mulch must go on top of the weed barrier. How then, I wondered, does it decompose and feed the soil? My friend Paul Van Middlesworth explains – the feeding occurs at the microscopic level, so once the mulch is sufficiently decomposed, when it rains the nutrients simply filter down through the weed barrier.

I created another region for the white stones:

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I continued laying weed barrier and covering with mulch, until done.

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Fully mulched. Time for some plants! To qualify for the rebate, a minimum of 40% of the area must be covered by water-friendly plants once they’ve reached maturity. I ended up with about 50 plants in different varieties, most of them quite small (1-gallon pot or thereabouts) as I wanted a fairly low growth height over the whole area, and also to keep the budget down. Selecting/purchasing/planting took the better part of a month, and I ended up with the following plants, all of them drought-tolerant to varying degrees:

  • Purple fountain grass
  • Mexican feather grass
  • Lantana (yellow, orange/red, purple)
  • Carmel Creeper (a california native)
  • Creeping Mahonia (a california native)
  • Greenmound Juniper
  • Rosemary (transplanted from the back garden)
  • Blue chalk sticks (succulent)
  • Cabbage-head agave
  • Pink ice plant
  • Agave americana marginata
  • Caribbean agave
  • Echeveria

These choices were influenced to an extent by my having done some research into what grows well in my climate zone, but mainly involved just picking out what looked nice in the low-water sections of the local nurseries.

It’s surprising how many plants and compost bags you can fit in the back of a smart car:

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I’ve since been inspired to do my own composting, so I shouldn’t need to buy compost next time around.

Planting entails the following. First, brush the mulch (or rocks) away from where the plant is to go. Then, cut an ‘X’ shape in the weed barrier, large enough so it can be folded back to accommodate the hole you’re about to dig. Dig a hole as deep as the pot, but twice the diameter. Remove the plant with its root-ball and soil, and place into the hole. Now, using some of the soil you dug out of the hole, mix it 50/50 with compost, and fill the gap with the mixture up to the level of the ground.

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Fold the weed barrier back into place and cut away any part of it which collides with the base of the plant. Replace the mulch. Water thoroughly, and then water ever day for a week or two until the plant has established roots, after which you can start to cut back the watering, tapering off to the target amount for the plant.

Repeat, per plant.

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The requirements satisfied, I submitted the project completion form, but I was still forced to do a great deal of hand-watering while plants established themselves. What I really needed was a drip system, so I turned my research efforts to this next.

Our mains water pressure is about 120 psi, which is much too high for drip components. So one of the elements of a typical drip system is a pressure regulator that reduces pressure to the level required by the down-stream components, typically about 25 psi. However, the pressure regulator for a drip system is generally made of plastic, and you may find that it ruptures after a while when subjected to mains pressure. On the advice of my friend Paul again, I installed a proper brass pressure regulator – not quite as heavy-duty as the one that supplies your house, but still robust enough that it won’t fail under mains pressure, and with an output range adjustable from 10 to 70 psi.

I installed the regulator upstream of all the irrigation valves – not just the one controlling the drip system, but also the ones controlling the existing sprinklers. Mains pressure is usually too high for ordinary pop-up garden sprinklers, which explains in part why they crack from time to time and need replacing in the absence of regulated pressure.

I had this region of space to fit my installation in, between the copper pipe and the first valve:

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Based on Paul’s suggestion, I used shut-off valves to set up a 2-way flow path, one for full mains pressure and one for regulated pressure, so it’s easily possible to switch between them for any reason. Here’s the layout I managed to squeeze into the available space:

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With reduced pressure now available, I began work on the drip system itself. I found that there are various kinds of manifold which convert a half-inch sprinkler riser so that you can feed quarter-inch drip tubes with it. I used an 8-way kind, made by Orbit, called Apollo-8:

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Each of the outlets on the manifold can be individually adjusted with a screw, and/or capped off completely. 5 of these manifolds provided more than sufficient capacity.

I ran quarter-inch drip line to the base of each plant, terminated mostly with 1 gph (gallons per hour) nozzles. I also had 0.5 gph and 2 gph nozzles on hand, which I occasionally used depending on the plant type.

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Lines were branched using T-junctions and secured with stakes.

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I arranged two nozzles to point to the base of every plant, watering it from opposite sides.

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When the lines are then covered with the mulch, the entire drip system is almost invisible. Remarkably, I even came across some white and tan-coloured drip line, which I used for camouflage against the stones. (Ok, maybe that’s overkill – the tubing is buried anyway.) I drilled through the plastic edging to feed water into the stone areas:

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I completed the drip installation in 2 days, during which time I installed over a hundred nozzles plus the associated junctions and stakes. The small angular nature of the plastic components, combined with the extreme fingertip force required to securely join them to the tubing, caused me to work my fingertips painfully raw. As a result of this they became leathery and hard after a couple of weeks. Then all the skin peeled off a couple of weeks later. Then the next layer peeled off a couple of weeks after that. I would recommend a somewhat more leisurely pace for drip installation.

It was all worth it, though. I like to think we have a nice-looking front garden where there used to be the dried-up remnants of a lawn.

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We eventually received a substantial cheque from the power company that more than reimbursed for the cost of materials. And, now that the plants are well-established, the volume of water required to keep them happy is a tiny fraction of what was once used on the same area.

 

 

 

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