By Susan Lewitt.
Imagine a natural, low-water garden blooming with the beautiful and unique flora of California native plants, attracting a large diversity of pollinators, birds, and butterflies. This is what you get with native plants that support the native fauna, instead of only utilizing exotic plants.
Two problematic exotic plants are St John’s Wort, Hypericum canariense and Common Lantana, Lantana camara. Common Lantana is an invasive species that colonizes native habitats and may hybridize with closely related native plants. As it spreads out, taking over areas from other plants, it gets woody, leggy, prickly, and unattractive. This plant does well in nutrient poor soils, the type soil that is best for native plants. At the same time, it produces a chemical that discourages other plant species.
Another plant to avoid, St John’s Wort, Hypericum canariense, is very invasive and problematic if you live anywhere near coastal sage scrub, and grassland habitats. It forms dense monocultures that crowd out native plants, ultimately having a negative effect on biodiversity. It’s a prolific seed producer of defiant seeds that are viable for up to 5 years and are spread by human foot traffic, and vehicles.
Instead of these, please consider Bush Poppy, Dendromecon rigida, and Cleveland Sage, Salvia clevelandii. Both species support many native pollinators including bees, butterflies, moths, and other insects.
Cleveland sage also attracts hummingbirds, as well as the following insects: Alfalfa Lopper Moth, Bilobed Looper Moth, Wavy-lined Emerald, Hawaiian Beet Webworm, Pheme subpunctala and Anstenoptilia marmarodactyla. The Bush Poppy attracts a moth known as Neoterpes edwardsata and many native bees including bumble bees. It also attracts bee flies, and fly beetles.
Bush Poppy, a cold tolerant shrub growing 3’ to 10’ tall by 2’ to 8’ wide, with yellow winter and spring flowers, is found on dry slopes as part of chaparral, and in open spaces in mixed evergreen forests. It grows tall enough to be considered a small tree. Bush poppy accepts rocky well-draining clay soil. It prefers full sun, and with sandy well-draining soil, water no more than once monthly during summer. It does well with Eastwood Manzanita, and Big Berry Manzanita and can be used for hedges, screens and as a dry garden background.
Another lovely native, Cleveland Sage can be found from the coast to inland areas including canyons, bluffs, and mesas as part of mixed chaparral or coastal sage scrub. This evergreen shrub attains a height of 4.5’ by about 8’ wide, with blue, purple, and lavender flowers that appear spring through summer. Cleveland Sage will do well in many different soil types, but the ideal soil is well drained with a mildly acidic to slightly alkaline (pH of 6.0 -8.0). It also accepts light from full sun to part shade. Once this plant is established it needs no summer watering, and tolerates cold to 20°F. It is great for bank stabilization, hummingbird gardens, bird gardens, Butterfly gardens and bee gardens. It is also deer resistant. Most native plants prefer to be with other natives indigenous to the same areas, and therefore good companions for Cleveland Sage are Chamise, Wooly Blue Curls, White Sage, California Buckwheat, California Coffeeberry, Toyon, Coastal Prickly Pear Cactus, Manzanita species and Yucca species.
As members of the San Diego Horticultural Society, you may want to experience the joys of exotic plants in your own backyard, but it comes at an expense, a loss to our biodiversity. San Diego will only remain a biodiversity hot spot if we support our native species. You can do this by dedicating a small part of your garden to California native plants. The two listed in this article are only examples, and with over 700 species listed on Calscape for San Diego, you are sure to find ones that please you!
Sources and Resources:
The Lantana Conundrum: How to choose a non-invasive species for your garden https://www.miamiherald.com/living/home-garden/article218656865.html
Invasive Plant Species Annual Work Plan, Implementation of Invasive Species Plan Recommendations Field season 2015 Prepared for: San Diego Association of Governments Prepared by: County of San Diego AWM Page 47, https://sdmmp.com/upload/projects/20160330_2357_202.pdf
Susan Lewitt has gone through training this summer to be a leader in the Climate Reality Project, a group led by Al Gore. This means she will be doing things such as talks and articles that relate to protecting our environment and slowing down or even reversing the effects of Climate Change.