Tom Karwin, On Gardening | Laws pertaining to the garden

Popular Flower Types

Roses are a classic, loved for their beauty and rich history of cultivation. They symbolize love and romance and are often associated with rebirth.

Tulips are popular for their beautiful colors and variety of shapes. They’re usually associated with spring but can be found all year round.

Today’s garden photo gallery features California native plants, which is a central focus on important new California state legislation that is the main topic of this column.

Let’s launch this topic.

The environment

California’s natural climate is similar to other regions of the world: the Mediterranean Basin, South Africa, Central Chile and Southwestern Australia. These regions have been described collectively as the Mediterranean climate regions.

Spice Bush (Calycanthus occidentalis). Native to the mountains of central and northern California, this bush grows to 9 feet tall and wide, with “fragrant, burgundy flowers, (April-August), that smell kind like a delicate red wine (if there is such a thing).” (Tom Karwin)

A more descriptive term is the summer-dry regions.

This climate pattern supports gardening in the Monterey Bay area with plants from all of the summer-dry regions, providing gardeners with an excellent range of options for their landscapes.

The pattern also supports California’s wildfire risks, typically beginning around October, after months without significant rainfall. It also can lead to drought conditions, resulting in limitations in the water supply.

Related past legislation

The state has a history of recognizing this pattern and has taken some actions to mitigate the wildfire risks and promote water conservation. In this column, we focus on water conservation.

According to California’s Department of Water Resources (DWR), “about half of urban water produced in California is used for landscape irrigation.” The recent history of responses to this practice includes the Water Conservation in Landscaping Act, adopted in 1990, effective in 1993 and updated in 2010.

The DWR also states, “The purpose of water-efficient landscape ordinances is to not only increase water efficiency but to improve environmental conditions in the built environment. Landscaping should be valued beyond the esthetic because landscapes replace habitat lost to development and provide many other related benefits such as improvements to public health, quality of life, climate change mitigation, energy and materials conservation, and increased property values.”

The Water Conservation in Landscaping Act required the DWR to develop a Model Water Efficient Landscape Ordinance (MWELO), which describes the standards of water-efficient landscaping for new or renovated landscapes. The act requires local agencies to either adopt the updated MWELO or a water-efficient landscape ordinance that is at least as effective as MWELO.

Douglas Iris +Iris douglasiana 'Canyon Snow'+. This cultivar is the most famous of all the Pacific Coast irises. The flowers are large +4-5 inches across+, yet very graceful and pure white with a golden patch in the center. It is exceptionally floriferous and the crisp whiteness of the flowers is set off by very dark green foliage. Flower stems are 1 foot tall and the plant makes a clump 4 feet across. (Tom Karwin) — Douglas Iris (Iris douglasiana ‘Canyon Snow’). This cultivar is the most famous of all the Pacific Coast irises. The flowers are large (4-5 inches across), yet very graceful and pure white with a golden patch in the center. It is exceptionally floriferous and the crisp whiteness of the flowers is set off by very dark green foliage. Flower stems are 1 foot tall and the plant makes a clump 4 feet across. (Tom Karwin)

The state has enacted several other water conservation laws that we do not summarize here. The MWELO, which is directly relevant to gardening and landscaping, is in effect today.

New legislation

In May 2023, the Assembly passed Assembly Bill 1573, a bill introduced by Assemblymember Laura Friedman (D-Burbank) aimed at replacing non-functional turf with water-conserving California native plants for commercial and public landscaping projects. AB 1573 would be the first bill of its kind to create a requirement for the use of California native plants.

AB 1573 updates MWELO to “require that all new or renovated non-residential areas install plants that meet specified criteria, and that prohibit the inclusion of non-functional turf in non-residential landscape projects after January 1, 2026.”

Note: AB1573 applies only to non-residential areas, and not home gardens. We will comment briefly below on its relevance for home gardens.

This bill focuses on non-functional turf. Functional turf means “a ground cover surface of turf located in a recreational use area of community space.” This includes such grassy areas as sports fields, golf courses, playgrounds, picnic grounds or pet exercise areas.

This “lose the lawn” approach addresses the water conservation objective because lawns require regular irrigation for successful maintenance, especially during the summer-dry season.

Wild Mock Orange +Philadelphus lewisii+. This deciduous shrub is native from northwestern California to the Sierra Nevada. It was first collected by Meriwether Lewis 1806 during the Lewis and Clark expedition. It grows to nine feet tall, with blossoms with a hint of pineapple. (Tom Karwin) — Wild Mock Orange (Philadelphus lewisii). This deciduous shrub is native from northwestern California to the Sierra Nevada. It was first collected by Meriwether Lewis in 1806 during the Lewis and Clark expedition. It grows to 9 feet tall, with blossoms with a hint of pineapple. (Tom Karwin)

Lawns also require the application of chemicals to support plant growth and discourage weeds. These chemicals eventually find their way into municipal water supplies, which is not good.

Finally, lawn expanses are monocultural by definition, which is not supportive of the wildlife.

Emphasis on California native plants

Since its establishment, the MWELO has neither prohibited nor required specific plant species. This provision probably was a concession to the plant nursery sector, which did not want constraints on the plants it wanted to sell. Negotiation of this bill resulted in changing the wording from “local native plants” to California native plants,” to provide more options for nurseries, landscapers and gardeners.

AB1573 requires that nonresidential landscapes include not less than 25% of California native plants, beginning Jan. 1, 2026. It also requires DWR to convene a working group to develop a strategic plan for new and renovated non-residential areas to reach a target of 75% of California native plants by Jan. 1, 2035.

The rationale for this requirement is that “landscapes using local native plants offer the greatest biological benefit to regional biodiversity, providing habitat and food to wildlife that has evolved to depend on specialized relationships with local native plants.”

This rationale echoes the teaching of entomologist Douglas Tallamy, who has written and spoken extensively about the importance of local native plants for wildlife.

Oregon Grape +Mahonia pinnata+. This shrub is shrub native to much of the Pacific coast. bears dainty yellow flowers in early summer and a dark blue berry that ripens late in the fall. The berries can be used to make jelly. (Tom Karwin) — Oregon Grape (Mahonia pinnata). This shrub is shrub native to much of the Pacific coast. bears dainty yellow flowers in early summer and a dark blue berry that ripens late in the fall. The berries can be used to make jelly. (Tom Karwin)

Road to adoption

This bill has been amended in the state Senate in June and July and might be further amended, but it appears to be on track to become law. (We will report on the bill’s progress in this column.)

As we have noted, AB 1573 does not apply to residential gardens. However, its goals for water conservation, biodiversity protection and urban greening are clearly applicable to home gardens.

Advance your gardening knowledge

Browse to tinyurl.com/59mtvnst to learn more about MWELO.

For an excellent resource for selecting California native plants, browse to calscape.org/. This resource is specifically listed in AB 1573.

Search the internet generally or Youtube.com in particular for Douglas Tallamy.

Enjoy your garden!

Mark your garden calendar

The Monterey Bay Dahlia Society is preparing its 2023 Show, to be presented on Saturday, Sept. 2 and Sunday, Sept. 3 in the Capitola Mall. This will be an extraordinary exhibit of selected dahlia blooms with entries from dahlia society members from San Leandro, San Francisco and San Luis Obispo, as well as the host society of the Monterey Bay area. Details will be included in next week’s On Gardening column.

The Monterey Bay Area Cactus and Succulent Society is preparing its 2023 Fall Show and Sale, to be held in September on Saturday the 16th and Sunday the 17th, in Watsonville. Details to follow. This event is a fine opportunity to add cacti and succulents to your garden, and to see dozens of outstanding plants exhibited by members of the society.

Tom Karwin is a past president of Friends of the UC Santa Cruz Arboretum and the Monterey Bay Iris Society, a past president and Lifetime Member of the Monterey Bay Area Cactus & Succulent Society, and a Lifetime UC Master Gardener (Certified 1999–2009). He is now a board member of the Santa Cruz Hostel Society, and active with the Pacific Horticultural Society. To view photos from his garden, https://www.facebook.com/ongardeningcom-566511763375123/ . For garden coaching info and an archive of On Gardening columns, visit ongardening.com for earlier columns or visit www.santacruzsentinel.com/ and search for “Karwin” for more recent columns. Email comments or questions to gardening@karwin.com.

Source: santacruzsentinel.com