California has traditionally gone through cycles of drought and it was an important factor when the Alcatraz Historic Gardens project began in 2003. Restoring an island full of plants did not make much sense if there was no fresh water to care for the rehabilitated gardens.
From the early days of the preservation, there were many common sense things that were done. The simple actions of designing drought tolerant gardens and timing the planting for the winter rains were easy enough to work with. There is such a wide variety of plants that can tolerate and even thrive with little water, that this was never a hindrance to the revival of the gardens. In fact, with now over ten years of first-hand experience on the island, we have built up a list of ‘Alcatraz tested’ plants that we provide on our website.
With rain collection being a known historic occurrence on the island, obtaining approval to once again collect rain water was straightforward enough – again, this had been always been in the garden work plan. However, despite filling the 12 000 gallon catchment to capacity each year, the shortage of rainfall is not saturating the soil. This means that the gardens begin the dry season already thirsty. For the past three years, we have begun to use our stored water in the early spring, instead of months later in the summer.
We have officially entered our fourth year of drought and we wanted to be pro-active and conserve where we can. This year we installed drip irrigation to save water by watering directly to the plants, avoiding overhead hand watering. So far, the rose terrace, Officers’ Row, and two sections of the Prisoner Gardens are on a drip line. We also installed a drip line to establish the native sedge lawn in front of the cellhouse. Once the historic lawn is established, two inches of water are required each summer month – a huge saving from the needed one inch per week for the typical turf grass. The irrigation in each garden area is divided into zones, so we can water sunny areas more, and the shaded corners less often. We have also attached inexpensive water meters to each of the hose pipes to keep track of how many gallons are being used on each garden area.
This year we also are using fine wood mulch to conserve soil moisture. Mulch was not used historically, but cultivated soil was the historic look. Now, we opt for a more permaculture ‘no-till’ approach with fine ¼” mulch on top. The no-till improves the health of the soil, and the mulch will conserve moisture in the soil. The wood chips will eventually decompose, adding to the organic matter in the soil.
Another water saving tip is to use perennials and not annuals. The majority of the garden plants are perennials. Perennials are better suited with typically deeper roots that can withstand dry conditions. Aside from the recent lawn planting, our last major planting was back in 2010. The perennials are now established and can tolerate drier soil. If you ever try to pull out a native California plant versus a non-native weed, the native will put up a fight while the non-native will easily pull right out.
As the summer continues, we may opt to not plant some of the beds which typically would be planted with annuals. For example, the raised beds in front of the greenhouse have been planted with spring and summer bulbs like cape tulip, Dutch iris and gladiolus followed by summer annuals. This year, we will likely omit planting the annuals and leave the raised beds fallow instead.
As our drought continues, I am seeing more lawns being ripped out and replaced with drought tolerant options, even artificial turf. A trip to see our gardens is well worth it to get ideas for your own backyard.