Drought-tolerant vernacular

An everyday resident of Colton has planted their trees in drought-busting watering basins
An everyday resident of Colton has planted their trees in drought-busting watering basins

The watering basin is a planting technique in which the plant or tree is not planted at ground level but instead is sunken so that water is directed downwards rather than away from the plant. As a result, the plant’s roots grow deeply rather than superficially. As an added benefit, the basins both catch rainwater and make deep watering by hand much easier. The technique is a hallmark of the irrigation-free landscapes we do, and, lo and behold, is something that just an everyday resident of Colton, California, has been doing too (see photo above).

And yet, when I first shopped this planting idea around to landscape professionals and arborists when we were pitching the irrigation-free idea, I was told by many that this was bad practice. Once we had secured public funding for the pilot Irrigation-Free Landscape and I was in the thick of installing it, there was actually a professional landscape designer working on the landscape next door. While I was planting one of numerous grasses in the basin-style of planting, she came up, grabbed the plant by the crown, and said, “Why are you planting it this way? Don’t you know you are supposed to plant the crown just above soil level?” I said that I was, but above the soil level of the bottom of the basin. She was not convinced. In another conversation with an arborist, I was told that you could not plant trees in this basin style, because their roots would grow out and around and eventually girdle the trees.

In fact, within educational materials and at workshops put out and on by professionals working in the realms of sustainability and landscapes, the watering basin is simply never suggested. Rather, you are to plant your drought tolerant plants in the same way you’ve planted any other plant, and you are to still tether them to an irrigation system. In short, within the worlds of landscape architecture, design, and arborists – the professionals one would think would be at the forefront of real techniques for sustainability – there is at one end a limited take on designing for drought, and on the other, outright resistance to new techniques.

The truth is, landscape professionals and designers can be woefully unwilling to step down from their lofty seats of professionalism and advanced degrees to look at what everyday people are doing in their own landscapes when responding to drought – both in terms of planting technique and design. No, this is not to say that landscape professionals know nothing; rather, it is to say that we don’t have all the answers. No one does. And sometimes those answers lie within the work of non-professionals and what kinds of drought-tolerant vernacular landscapes they are making.

And so we come full circle to this resident in Colton, who clearly understood on an intuitive level that given low rainfall and high heat in a place like Colton, planting the trees in basins makes perfect sense, and the resident’s work has resulted in plants that are surviving and thriving.

-John Kamp

Surviving irrigation-free

Coleonema pulchrum, a commonly irrigated landscape plant,  growing irrigation-free in Oakland
Coleonema pulchrum, a commonly irrigated landscape plant, growing irrigation-free in Oakland

There are so many plants of the landscape that we assume are water-loving because they are never given a chance to prove otherwise, and because we don’t look into their native growing conditions to see just how little water they need to grow and thrive. Coleonema pulchrum is just such a plant. With its chartreuse leaves and pink flowers, it’s a much-loved plant in Northern California, offering a bright spot within what could be a washed-out landscape of dull greens and grays. Yet what folks probably don’t know is that this plant is native to a summer-dry, winter-wet region of South Africa and thus for many months out of the year has to tough it out with no water.

Indeed, even a drought-tolerant plant will need water up front in order to get established, but once established, the watering can be phased out, and the plant will thank you for it. Plants that are native to regions where drought is simply part of the climate oftentimes simply cannot absorb enough water from irrigation if they are watered during their period of dormancy as their root systems go into a sort of slumber during this time. In a worst-case scenario, their roots will rot, or the plant will grow much larger and faster than it should, ultimately opening out on itself and taking on a leggy appearance that no one particularly likes.

In our inveterate efforts to show that irrigation-free is all around us, we hope that folks will start to open their eyes to other plants they’ve seen growing irrigation-free and doing just fine.

When a forest isn’t a forest

A prairie savannah in what had recently been forest in Phil Hardberger Park, San Antonio, TX. Photo from the Phil Hardberger Park Conservancy.
A prairie savannah in what had once been forest in Phil Hardberger Park, San Antonio, TX. Photo from the Phil Hardberger Park Conservancy.

We so often think that forest is the natural result of just letting nature be and that to see forest is to see an indication of a healthy ecosystem. Yet we forget that many ecosystems are actually not forest-based at all, or else they are a mix of forest and other types of ecologies, such as grasslands and prairies. Years of fire suppression and mismanagement in the US have actually allowed many formerly grassland and savannah (mix of grassland and forest) ecologies to become completely dominated by forest, which is then often dominated by one or two species that have simply outcompeted everything else.

This scenario was very much the case within what is now Phil Hardberger Park in San Antonio. Years of fire suppression, grazing, and dairy ranching on the site had turned what had once been prairie, prairie savannah, and some forest, into basically all forest. So embedded had the forest look and feel of the area become that within the local narrative of the place people simply saw it as natural and having always been there. Recently, when the site was to be re-envisioned as a park, designers and ecologists had to contend with vast stands of juniper that had worked their way in and basically choked out native grasses, oaks, and perennials.

This foresting of places that were never forests to begin with is nothing new in American history. In fact, much of California was grassland before European settlers arrived. In his book, Trees in Paradise, Jared Farmer writes that settlers coming to the Far West wanted to “complete” the land by foresting it. “They forced grasslands and wetlands to metamorphose into fields, orchards, and garden cities,” he writes. To use a term of the time, they “emparadised” it. These longstanding efforts, combined with years of fire suppression, have transformed parts of California into hybrid manmade-natural tree-dominant ecologies that didn’t exist prior to the arrival of the Spanish some 450 years ago.

Of course, the lessons we can learn from these examples are not that trees don’t have their place in spaces where perhaps they once didn’t grow. Our urban and suburban landscapes are brimming with things that didn’t used to be there – pavement, right angles, roofs, to name a few – so to make the case that trees shouldn’t be there because they weren’t there before doesn’t really hold water. Not to mention that we need street trees more than even, given the realities of the urban heat island effect and climate change. Yet when it comes to our less urbanized and wilder spaces and places, rethinking the role of the tree in ecologies that were not ever forest is a much-needed endeavor. To restore these places back to prairie or Savannah is a way of ensuring that they are able to grow and evolve in a way that ultimately reaches a balance, so that one species – such as juniper – doesn’t become so dominant as to prevent biodiversity from flourishing. As a result, intense, long-term maintenance of the space does not have to be a prolonged and expensive reality.

Rethinking the magnolia

Two dead magnolia trees in Alhambra, California. Victims of drought and a lack of foresight.
Two dead magnolia trees in Alhambra, California. Victims of drought and a lack of foresight.

While past peak, the years-long drought in California is showing its effects in slo-mo delay, coming on in the form of many a street tree stressed to the point of just not being able to take it anymore. Nowhere can this phenomenon be seen more than in Southern Calfifornia, where one of the street trees hardest hit has been the southern magnolia / Magnolia grandiflora. A tree native to the rain-abundant American South, it probably never should have been planted in Southern California at all, where rainfall is typically a scant 12 – 15″ during a good year. But, alas, like so many consumer goods, trees come in and out of fashion, regardless of what practical considerations there may be. So in the ’50s and ’60s street upon street were planted with magnolias in places like Hollywood, and Beverly Hills, and Alhambra – all arid regions and all requiring that the magnolias be irrigated generously in order to survive and thrive. So when the watering bans then hit a few years ago and folks were told to let their lawns and parkways go brown, the trees were never ready for the suddenly parched conditions. Many became stressed, and now, some years later, many are dying. As a result, the cooling shade and outdoor-room-creating canopies will be lost, and we will be left with wide streets and excessive sunlight and heat.

A jacaranda, cactus, and yuccas growing and thriving in hot Riverside County.
A jacaranda, cactus, and yuccas growing and thriving in hot Riverside County.

While devastating for the character of so many neighborhoods and the quality of life of our cities, we need to view this loss of trees as an opportunity to rethink what we plant and how. Even before the drought and worsening global warming, LA was a dry place. This simple truism is not going to change in the foreseeable future, and thus we must start planting trees that can handle these hotter and drier conditions – and that can handle them for the long haul. All it takes is a little observation to see which trees are still pushing on and looking good. In the photo above, you can see that this jacaranda – a tree actually not considered one of the most drought tolerant – and its surrounding plants are doing just fine – more than fine – and this is in hot hot Riverside County, in a parkway space surrounded by heat-absorbing asphalt and concrete. What other trees do you see still doing well? What other trees that you haven’t seen could be invited in, to create amazing tree-lined boulevards for the 21st century? Mesquites, acacias, jacarandas, palo verdes, tristanias – and the list goes on. We cannot keep doing what we’ve always done; it’s simply not working, and we’re seeing our lack of foresight in the form of sadly dying trees and sunbaked parkways. Let’s do better this time around.

Vacant Lands installation in SF

The site for the first Vacant Lands installation by Prairieform in San Francisco's Presidio.

We are spectacularly thrilled to announce that we will be doing our first Vacant Lands installation right here in San Francisco. The installation will be featured as part of the Architecture as Pedestal exhibition, which will be held on October 29 and 30 in the Presidio. To see a video of the site with the glorious fog rolling in, you may visit our Instagram page HERE.