Sunday, July 23, 2017

Exploring a Rain Garden from the experts

We San Antonio gardeners have by necessity sought out drought tolerant plants to use less water and lose fewer plants to the intense summer heat.  But what happens when there is too much rain all at once, when runoff becomes an issue?  Recent buzz about rain gardens, which serve to slow down and filter storm runoff, motivated me to visit the Rain Garden at San Antonio River Authority (SARA) offices last Spring.  SARA protects the San Antonio River watershed for water supply and conservation.  SARA's Sustainable Landscape Superintendent, Lee Marlowe, gives an excellent presentation on the concept and installation of this rain garden so I'd learned quite a bit about it in advance.  If you're in San Antonio, Lee currently stars in a SARA public information TV spot featuring this rain garden.  While SARA's main office is south of downtown along the River Walk, this office with the rain garden is at 600 East Euclid just north of downtown.

Let's see how pros do a rain garden.  The purpose of a rain garden is to slow down and filter rain water before it reaches our water sources.  When I first heard about the SARA rain garden I envisioned a channel with rocks in the bottom.  This is way more than that.  I should have known better since the plants were selected by Lee and her team.  Lee, aka "the plant lady" for SARA, is a native plant expert who can rattle off the ID of some pretty rare plants and the person largely responsible for restoring native plants to miles of San Antonio River banks over the past few years.  Her expertise shows in this beautiful urban garden.

Did I mention urban?  I-35 is right there in the background so all the freeway goop washes off onto their property during rain events.  Downtown San Antonio is just on the other side of the freeway.  SARA's rain garden also filters runoff from 9,000 s.f. of roof so it's a little deeper and larger than most rain gardens which is why they used heavy construction equipment.  While not something you'd have available for your yard we can find plenty of inspiration and ideas to take home.  LID or Low-impact Development features such as rain gardens are taking on more importance as cities like San Antonio assess fees for impervious surfaces to raise funds for drainage improvements.

A no mowing sign in case there are questions.

The site was a flat, boring strip of lawn just like this area along East Euclid Street near the SARA visitor entrance.  To the right is the rain garden running along side the building.

All these plants are commonly sold in local nurseries making the rain garden an example for the community.

Dyschoriste linearis or Snake herb fills the bottom of the channel to filter the tainted rain runoff.

Scutellaria wrightii blooms add color.

Mexican Olive (Cordia boissieri) trees run at intervals along the building with Texas sage, Leucophyllum frutescens filling in under the windows.  Muhlenbergia lindheimeri grasses add another layer of texture along the row.

In her presentation on this rain garden, Lee notes the amazing number of species of birds, bugs, and butterflies that have flocked to this previously wildlife free zone.  I was here a little early to spot much in the way of activity though she did ask about my observations.

A gray swath of Woolly stemodia stands out among the green while Purple Coneflower (Echinacea purpurea), Mealy Blue Sage (Salvia farinacea), Gulf Muly (Muhlenbergia capillaris) a little lower on the slope and orange-gold Four-nerve daisy (Tetraneuras scaposa) add color to the mix.

Runoff also channels into the rain garden from the parking lot via grates like this.   Frogfruit (Phyla nodiflora) right, blue skullcap left

Wish I could grow coneflowers like these.  They should be easy to grow but for some reason I've killed way too many of them.  Time to try again.

A small field of white and yellow Blackfoot Daisy (Melampodium leucanthum) topping a rise combines beautifully with Four-nerve daisies heading down the hill.

Well done SARA team!  A rain garden to be appreciated as a beautiful, functional native plant garden.  If you haven't seen Lee's presentation on this garden yet I highly recommend it.  Follow San Antonio River Authority and SAWS (San Antonio Water System) on Facebook for notification.

Now where can I place a rain garden?   Mine would obviously be a modified version.  There may be incentives on the way soon.  While San Antonio lowers impervious surface fees for commercial properties with LID features, there is no similar option for homeowners at this time although this oversight will hopefully be corrected sometime in the future.

To learn more about rain gardens in San Antonio:

Residential Rain Garden
Rain Garden in Action with Lee Marlowe and Heather Ginsburg of SAWS


  1. I'm always encouraged when I see municipalities take responsibility for conservation. I wish more cities were as proactive as San Antonio! LA County doesn't get the monsoonal rains you do but we can still benefit from keeping what measly rain we get on site rather than allowing it to dump into the ocean.

    1. It's time to convert those awful concrete culverts to something more sustainable.

  2. What a great space. I love that there is some signage to help folks learn about what is going on at that site.

    1. I was so impressed with how it looked in person.

  3. Cape Town has a long way to go before we tax paving and stormwater runoff.
    Such a battle to convince people who whine about wasted water going to the sea - that -
    they need to at least keep their own stormwater in their garden.

    1. It's the small things and we have added a series of short terraces to help hold water.

  4. Good work on how to deal with / tax excessive paving, but even better on this landscape conversion. Great plant combos. Yes, rain gardens / bioswales / LID or GI are some variant terms on imitating dry-to-deluge arroyo or wash environments...makes sense. I bet soil types might be at play in coneflowers?

    1. Certainly my thin clay over rock is a problem and I've been amending the soil with compost annually so there may be a better spot now.


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