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Filoli’s Drought Response

More Information

Click on the images below to visit each online resource and article.


UC logo

National Integrated Drought Information System

Drought In California page

Save Our Water

California Dept. of Water Resources and the Assoc. of California Water Agencies

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UC – Drought Info

University of California, California Institute for Water Resources

Sustainable San Mateo County
Sustainable San Mateo County

Supply and Demand

Master Gardeners
Master Gardeners

San Mateo Co. and San Francisco Co: Water Wisdom in a Drought

Recent Drought Coverage in the San Francisco Chronicle:

California Drought

Drought tips: 15 easy ways to save water now

view of north field and back of house

A view across the north field to the back of the House. Photo by Jerry Barrack.

With record low rainfall for the 2013-14 season, and below average rainfall for the 2014–15 season, Filoli is taking several measures to reduce its water use this spring, summer and fall. Typically our garden uses considerable irrigation during the summer months, but our efforts should significantly reduce that quantity this year. Filoli reduced its overall water use by 34% in 2014 even though we experienced a 20% increase in visitation.

We already do quite a lot to prevent the over use of water at Filoli. Our irrigation schedules are based on CIMIS (California Irrigation Management Information System), which uses historic weather data to predict evapo–traspiration (a measure of plant water use), and plant requirements based on plant type (turf vs. annuals vs. woody plants). This is then fine–tuned for specific microclimates within the garden like slopes, turf adjacent to a hedge, compacted soil, etc. With a good irrigation system, we are able to keep our plants supplied with just enough water to thrive, without much waste.

The other key to having an effective and efficient irrigation system is continuous monitoring by trained horticulturists checking the system for any troubles. Filoli staff perform a complete check of all our irrigation systems each spring correcting for broken or misaligned sprinkler heads and inspect for any cracked and broken parts. Then, throughout the dry season, our irrigation systems are monitored and dry areas are regularly probed to check the water content of the soil. An irrigation system is only as good as the horticulturists who maintain it. You cannot be on autopilot and expect the system to take care of itself.

In the face of this severe drought, our plan is operate under a philosophy of allowing parts of the garden to thrive, while other parts will be irrigated just enough so that the plants are able to survive. All display beds and highly visible sections of the garden will receive our standard irrigation amounts. A few of our less visible lawns will be allowed to go mostly or completely dry. Woody plants can survive with 40% of normal irrigation, so many of our orchards and other woody plants will be irrigated significantly less this summer and fall.

Cost of Converting to
Efficient Sprinkler Heads

In 2014, we converted the Sunken Garden lawn heads to the water-saving MP Rotator heads. These heads can save as much as 30% on water as they apply water in streams instead of mist–creating sprays. But the water saving comes with an initial steep investment. MP Rotator heads cost $5.00 vs. the $0.25 Rainbird heads we’ve traditionally used. This summer, we plan to replace the heads in the lawn south of the Garden House. At 48 heads in this lawn, that is $240 in initial costs, but absolutely worth the savings in water use.

Filoli’s Planned Water Conservation Measures

  1. Irrigate woody plants at 40% of normal levels.
  2. Refrain from irrigating olive orchards, blue Atlas cedars and other stands or woody plants normally receiving monthly summer irrigation.
  3. Allow many low-visibility lawns to go dry for the summer. Currently planning for 40% (40,000 sq ft) of turf to receive either no or reduced irrigation.
  4. Converting two lawns to mulched areas.
  5. Partially reduce the number of containers in the garden and, for the most part, choose more drought tolerant varieties, like Pelargoniums (geraniums).
  6. Plant begonias, which are drought tolerant, in several annual beds.
  7. Turf Areas scheduled for significant water reductions in 2015:
    Group one— irrigation already turned off:
    North Lower Lawn terrace (field view to the north)
    North Ballroom lawn
    Service Courtyard lawn (outside administration offices)
    High Place lawns- upper and lower terraces

    Group two— reduced to 40% with supplemental watering of adjacent woody plants where needed:
    North and South Upper terraces (behind house)
    Behind Swimming Pool Pavilion
    Both Yew Allées along swimming pool
    Wedding place terrace lawns
    High Place Yew Allée

Recommendations For Your Garden

Many of these practices apply to any year in California, but they are particularly applicable for 2015:

  1. Transition a portion, or all, of your turf area to an alternate use. With improvements in artificial turf products, converting to a no-water, no-mow product is an easy solution. Other choices are mulching over turf areas completely, or a combination of mulch and a more drought-tolerant palette of California natives, succulents, Mediterranean plants, etc.
  2. Thoroughly check your irrigation system for any troubles. If you are not comfortable performing this type of check yourself, consult an irrigation specialist.
  3. Regularly monitor your irrigation system throughout the year to identify troubles as they arise and address these as quickly as possible.
  4. Make sure to schedule irrigations for pre- or post dawn start times with the exception to plants susceptible to flower fungal disease (Botrytis) like petunias.
  5. Consider transitioning to drip or micro-spray irrigation wherever possible to conserve water.
  6. Cut back irrigation of woody plants so that they receive 40% of what they have in the past.
  7. Refrain from adding new plants to your garden this year. Choose low water using California natives, Mediterranean plants or succulents if you must plant.
  8. Faced with reduced food in their natural environment, expect deer to be more brazen about feeding any time of day and feeding on plants that are typically considered “deer proof.” If browsing deer have been an issue in your garden in the past, this may be a good year to consider installing a fence.