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.

With rains come blooms

echinops lateritia in bloom at the UC Berkeley Botanical Gardens

With all the rain this year, the cacti at the UC Berkeley Botanical Gardens are putting on quite the show right now. If you have never been, now is the time to go. Not only do you get to see these insanely huge cactus flowers live and in the flesh, but you get to experience sweeping views down a canyon and out into the Bay, with the Golden Gate Bridge just shy of the horizon. And there are newts o plenty swimming in the pond in the Asian Garden area. You will be stupefied by their gentle cuteness. What’s not to love?

John Kamp