By Kim Schwind, UC Master Gardener of Butte County, April 5, 2019
In recent months there has been disturbing news about the decline of the Western Monarch population. The North American Monarch Butterfly (Danaus plexippus) is a familiar and charismatic insect. It is known for its amazing migration and its reliance on one plant in particular: milkweed.
There are many hazards along the way. The monarchs that start their migration in the spring will not live long, so in order to lay their eggs they must locate a stand of milkweed. Once laid, it takes three to five days for the eggs to hatch into caterpillars. Monarch caterpillars feed exclusively on milkweed. They grow and molt through five developmental stages over a span of 14 to 18 days. Each caterpillar then spins silk attaching itself to a milkweed leaf or stem and forms a chrysalis (hardened outer protector). After about 10 days it emerges from the chrysalis as an adult butterfly. The lifespan of this adult butterfly is very short – just two to six weeks. In that time it feeds on nectar and continues the migration journey. It might take three or four generations to reach the end of the migration. The last generation (which has a lifespan of months rather than weeks) flies back to its ancestral start where it overwinters in large trees. In Pacific Grove, California they overwinter in a large grove of eucalyptus trees.
The reasons for Monarch decline are varied, and include habitat loss, disease and predation, use of herbicides and pesticides, and climate change.
What can be done to help these beautiful pollinators?
Backyard gardeners can help restore breeding and migratory habitat here in
Milkweed is a perennial plant. It is named for its milky, latex sap. Milkweed is drought tolerant and deer resistant. The native species are not invasive. Milkweed plants develop large fleshy seed pods. When the seeds are mature, the pods pop open, freeing the seeds. Attached to the seeds are fine tufts of hairs (called pappus) which aid dispersal of the seeds: as the wind blows, it catches the silky hairs, carrying the seeds away from the plant. The seeds can be collected from the pods for later propagation or left alone to re-seed themselves.
Home gardeners can aid the Monarch population by adding milkweed to their landscape, pollinator garden, herb garden, or even a patio container. If you own a larger plot of land you might consider letting some of it remain wild, so that the wild nectar producing flowers are available not only for butterflies, but for other pollinators as well. Hedgerows that include milkweed and nectar flowers are a wonderful way of attracting wildlife and pollinators. Creating a monarch way station (a garden that includes milkweed, nectar flowers and a water source) is a nice addition to a community or school garden.
Milkweed is also a great host plant for many other beneficial insects including bees, beetles, and lady beetles (ladybugs). It will also attract a yellow aphid known as Oleander aphid. This aphid will not destroy the plant and it will not infest nearby roses or vegetable gardens. It is plant specific: think of the Oleander aphid as food for the lady beetles.
Avoid using pesticides or herbicides that might damage these breeding and feeding areas. Use caution where you plant the seeds, as milkweed can be toxic to livestock.
Area specific milkweed seeds can be purchased online. You can also find milkweed plants at our upcoming Master Gardener plant sale on Saturday, April 20th, from 10 a.m. to 2 p.m. at our Demonstration Garden at Patrick Ranch, located at 10381 Midway, Durham. For more information on the plant sale, see the Butte County Master Gardener website at https://ucanr.edu/sites/bcmg/
For more information on Monarchs and milkweed, visit the Xerces Society for Invertebrate Conservation. Their website also includes area-specific nectar plant lists.
Finally, local butterfly experts highly recommend Monarchs and Milkweed: A Migrating Butterfly, a Poisonous Plant, and Their Remarkable Story of Coevolution by Anurag Agrawal (2017).An interview with Agrawal on this subject recently aired locally on the North State Public Radio program Cultivating Place, and is available as a podcast here.
For more information on gardening in our area, visit our website Butte County Master Gardener. If you have a gardening question or problem, call our Hotline at (530) 538-7201 or email us at firstname.lastname@example.org.
Finding an Ecological Niche: A Three-Part Series on Selected Foothill Woodland and Chaparral Species, Part 3 of 3: The Buckeye
By Laura Lukes, UC Master Gardener of Butte County, March 22, 2019
[Note: Buckeye (Aesculus californica), gray pine (Pinus sabiniana), and blue oak (Quercus douglasii) are tree species that thrive in rugged local foothill woodland and chaparral habitat. In the last two editions, we covered the blue oak and the gray pine. This final installment explores the buckeye. All three species rely on adaptive strategies evolved over time allowing them to thrive in their challenging environment.]
Aesculus californica is a woody shrub or small tree that has adapted to a variety of microclimates in our state: it can be found along the central coast and in the foothill and lower montane elevations of the Sierra Nevada and Cascade Ranges. It grows as far north as the foothills of the Siskiyou Mountains, and as far south as northern Los Angeles County. Native buckeyes can grow in elevations as high as 4,000 feet (one source claims 5,500 feet), but most commonly these plants colonize the foothill altitudes. A true California native, it is found nowhere else in the world.
The California buckeye's variable height attests to its nuanced response to climatic conditions: in northern reaches, the buckeye is shrubby and squat (about 12 feet tall). Further south, it can reach tree-like statures of up to 30 feet. In the kinder habitat conditions of the Coast Range, an Aesculus californica has attained sufficient proportions to be registered as a California Big Tree. That one, in Swanton Pacific Ranch, measures 46 feet high, has a trunk circumference of 176 inches, and a crown that spreads to 60 feet.
The seeds of Aesculus californica are contained in a thick leathery husk, which splits when dried, and are the largest of any non-tropical plant species. These seeds (also called nuts) are the origin of both of its common names: buckeye and horse chestnut. According to Cal Poly's Select Tree web page, Native Americans called the seed "hetuck" (buck eye) because its markings resemble the eye of a deer. The seeds also resemble those of the European sweet chestnut (Castanea sativa). And there the resemblance ends, as the heavy seeds of the California buckeye are toxic, thus limiting its reproductive dispersal strategies to rolling downhill or being conveyed by water.
In addition to toxic seeds, the buckeye's leaves, shoots, and flowers are poisonous. All contain the neurotoxin glycoside aesculin, which is destructive to red blood cells. Although ruminants can feed on very young shoots without harm, and squirrels are able to tolerate the nuts, this toxin protects the buckeye from damage or death by grazing animals. As Ridgeway points out, “the sweetly fragrant flowers of this tree provide a rich pollen and nectar source for native bees, hummingbirds, and many species of butterflies” and are toxic only to non-native honey bees. Honey bees that do survive after ingesting buckeye toxins reproduce “buckeyed-bees” that hatch with deformed, crippled wings or malformed legs and bodies.
A deep taproot allows the buckeye to find water in even the driest of years. A fully developed root system also helps mature California buckeyes to survive drought by enabling the plant to both save and draw on food and water reserves. According to USDA research, California buckeyes recover rapidly following a fire, sending out new shoots during the first growing season, and growing rapidly in following seasons. Some buckeyes can exceed their pre-fire biomass within a few years. They can sprout from their root crown after top-kill by fire within a few weeks, even in the summer months. The USDA also notes that buckeye seeds will probably not survive fire because they are highly susceptible to desiccation by heat.
The same toxin that limited the buckeye seed to a food source only in times of hunger was used to snare a more delicious high protein food source. Native California tribes, including the Pomo, Yokut, and Luiseño, cleverly used the ground-up powder of buckeye seeds to stupefy schools of fish in small streams, making them easier to catch. And the smooth, straight branches of the buckeye made it useful to native peoples as a bow drill and a fire drill.
Our native buckeye is a California beauty and a hardy survivor in some of the least hospitable habitats. In the biological contest for survival, this tough, gorgeous plant holds a winning hand.
For more information on gardening in our area, visit the Butte County Master Gardener web page at: http://ucanr.edu/sites/bcmg/. If you have a gardening question or problem, call our Hotline at (530) 538-720l.
Sue Ridgeway, The Bisexual California Buckeye – sinner or survivalist? UCANR website: http://sonomamg.ucanr.edu/Plant_of_the_Month/Aesculus_californica_-_California_buckeye/
M. Kat Anderson, Tending the Wild: Native American Knowledge and the Management of California's Natural Resources (University of California Press, 2005).
Urban Forests Ecosystem Institute at CalPoly SelecTree: https://selectree.calpoly.edu/tree-detail/Aesculus-californica
Stanford Trees: https://trees.stanford.edu/ENCYC/AEScal.htm
USDA: FEIS: FIRE EFFECTS INFORMATION SYSTEM: https://www.fs.fed.us/database/feis/plants/tree/aescal/all.html#FIRE%20ECOLOGY
Carol Bornstein, David Fross, and Bart O'Brien, California Native Plants for the Garden (Cachuma Press, 2005)
Buckeye's namesake is its large nut: By John Morgan from Walnut Creek, CA, USA - IMG_8269, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=25021982
Buckeye flower spike: By Eugene Zelenko - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=2103608
Buckeye leafs out early in the spring: By Eugene Zelenko - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=18732498
By Brent McGhie, UC Master Gardener of Butte County, January 11, 2019
Fire is a normal part of the natural environment in California, so if you live in the wildland-urban interface (WUI), it's not so much a question of if, but of when your home will be exposed to wildfire. With this thought and the devastation of the Camp Fire fresh in mind, many Butte County property owners may be thinking about creating a fire-resistant landscape around their homes. Not only is this a prudent course of action, a 2005 revision of the California Public Resources Code (PRC 4291) requires that property owners create 100 feet (or to the property line) of defensible space around homes and buildings. Defensible space is defined as the area around a structure where the landscape is designed and maintained to decrease fire danger. Creating defensible space also gives firefighters an opportunity to safely protect your home.
If a fire reaches the crown of a tree, its heat intensity increases and this can increase the combustibility of surrounding vegetation. Low tree branches create fuel ladders that allow fires to climb into a tree. To prevent fires from ‘crowning,' these ladder fuels must be eliminated. Cal Fire recommends that the lower branches of a mature tree should be pruned to create a clearance of three times the height of the shrubs beneath it. For example if a shrub is four feet tall, the tree should be pruned so that there is 12 feet of clearance between the top of the shrub and the lowest branches of the tree. For younger trees, the lower one-third of branches should be removed.
The area that is 30 feet closest to a home is often called the “home defense zone” or, as Cal Fire puts it, the “Lean, Clean and Green Zone.” In this area, highly flammable fuels should be eliminated or minimized and widely spaced plants should be kept green and well irrigated. Vegetation in this zone should be comprised of shorter plants such as grasses and non-woody flowers. If shrubs or trees are planted, they should be fire-resistant plants such as deciduous trees (which shed their leaves in the fall) or non-woody natives and other perennials such as salvias. Fire-resistant ground covers are also an acceptable choice for this area. Avoid planting broadleaf evergreens (like holly and coyote bush), conifers (like pines, junipers, cedars, and firs) and palms, because they are highly flammable.
When planning a firewise landscape, the contribution of hardscape features should not be overlooked. Decomposed granite, cement, asphalt or gravel pathways and driveways make effective firebreaks. Structures such as patios and masonry walls and water features like pools, ponds, and streams will also impede the advance of a fire.
Before moving beyond the 30-foot home defense zone, mention should be made of items that do not belong too close to a home. Most propane tanks should be located a minimum of 10 feet from any structure, and woodpiles should be at least 30 feet away. A cord of seasoned firewood contains the energy equivalent of approximately 174 gallons of gasoline! Would you store that much gasoline on your porch? Also, flammable liquids such as gasoline, paint thinner and turpentine should be properly stored away from ignition sources and combustibles.
The outer 70 feet of the defensible space is called the “reduced fuel zone.” As with the home defense zone, plants in this zone should be well spaced horizontally and separated vertically to eliminate fire ladders. Fire resistant plants should also be used here. Most surface litter such as leaves, pine needles, and twigs should be removed so that this layer is no more than three inches deep. Dead annual grasses should be mowed to a height of no more than four inches. Mature trees without shrubs growing beneath them should be limbed to a height of six feet above the ground. All plants should receive adequate water and dead branches in trees and shrubs should be regularly removed. As noted in the UC Cooperative Extension's fact sheet on defensible space, “The goal of brush clearance is not to remove all vegetation. When done well, cleared areas should still include enough well-spaced and judiciously pruned plants to protect against excessive erosion and provide wildlife habitat.”
If organic mulches are used in the reduced-fuel zone, a 2008 study showed that a mulch of composted wood chips spread two to three inches deep showed the slowest fire-spread rate of the eight mulches tested. A potential disadvantage of wood chip mulches is that they tend to smolder and can be difficult to extinguish. In general, fine, stringy mulches such as shredded bark burn more rapidly than larger chunks.
Establishing defensible space can be summarized by the following three R's: 1) Remove dead and dying plant material; 2) Reduce the density of vegetation and ladder fuels; 3) Replace hazardous vegetation with less flammable, well-irrigated fire resistant plants.
Further information on fire safety for homeowners can be found in two highly recommended Cal Fire publications: “Homeowners Checklist – How to Make Your Home Fire Safe” and “Why 100 Feet?” And for property owners who are considering landscaping from scratch, the Sonoma-Marin Saving Water Partnership has developed eight fire-rebuild landscape design plans that are well worth considering.
For more information on creating fire resistant landscapes, see the Fire-Safe Landscape section of the UC Master Gardeners of Butte County website. For other topics of interest to local gardeners please visit our home page. And if you have a gardening question or problem, call the Master Gardener Hotline at (530) 538-7201.
By Laura Lukes, UC Master Gardener of Butte County, December 14, 2018
The chemistry of soil hydrophobia is fairly basic. Plant materials that burn hot release a waxy substance that penetrates the soil while still in gas form. It takes very high temperatures to produce this gas which coats soil particles when it cools and becomes solid. To the naked eye, hydrophobic soils look like their non-hydrophobic counterparts. But biologically speaking, they have now become latent disaster zones.
Runoff caused by rainfall on water-shedding soils can also cause the loss of fertile topsoil. And it can clog water conveyance facilities including manmade culverts, gutters, and ditches, as well as streams and rivers. The upside of rainfall on soil hydrophobicity is that, generally speaking, water repellency weakens with each rain event.
The type of soil and the intensity of the fire determine how deeply hydrophobia penetrates the soil, and how long the condition persists. Paradoxically, the fastest draining soils, (light, sandy soils with large pores) are the most prone to post fire hydrophobicity because they transmit the heat more easily than heavy, dense, clay soils. Soil types within the approximately 240 square miles burned by the Camp Fire vary from the sandy loam found in parts of Butte Creek Canyon to the red, rocky soils of the ridge communities. In general, the bulk of the burned area is perched atop the Tuscan formation. In its Soil Survey of Butte Area, California, Parts of Butte and Plumas Counties, the Natural Resources Conservation Service (NRCS) notes that these ridges “consist mainly of mudflow breccia, volcanic sandstone, and volcanic conglomerate.” The soils sitting on these thick layers of volcanic bedrock tend to be naturally clayey and slow draining.
Prescriptions for large scale mitigation within the burnt forested public lands, and the large acreages of undeveloped private landholdings, are outside of the scope of this article. For the private landowner, the following steps outlined by Douglas Kent in his Press Democrat article can be taken to lessen and control the damage caused by the treacherous combination of heavy rain and burn-scarred soils. These procedures can be followed if the homeowner is 1) allowed back onto his / her property and 2) able to stay long enough to put these measures in place.
To hold your ground:
- Clear drainage systems such as culverts, diversion ditches, or narrow swales, of debris. Clogged drains are a primary cause of erosion, even without fire damage.
- Divert water from areas originally designed to sheet runoff to the landscape: instead, redirect the runoff towards your newly cleared drainage systems or, if they exist, towards storm drain systems such as gutters. Use sandbags, diversion ditches, boards stacked on top of one another and staked in place, dry stacked walls, or bales to redirect water flow.
- Minimize foot and equipment traffic on burned landscapes. Such traffic can further compact already damaged soils on flat areas, and can weaken soil bonds and dislodge soil particles on slopes. Develop plans to restore your injured landscape before tramping on it, and keep all traffic to the bare minimum during restoration activities.
- Leave non-toxic debris in place wherever possible. Burnt plant remnants and other garden features can protect the landscape from wind and water erosion, and help protect any seeds and plants that survived the fire.
You may not want (or be able) to return to your property within the perimeter of the Camp Fire. On behalf of the Butte County Master Gardener Program, we hope this information will help you in the process of healing the scars on your land and those in your soul. If you don't, we hope you find peace and beauty wherever you choose to land and to landscape.
For more information on dealing with the effects of wildfire on soil, and landscaping with the possibility of fire in mind, see the Fire-Safe Landscape section of the UC Master Gardeners of Butte County website. Among other resources, see “The New Normal: Rebuilding Soil After Fire,” a PowerPoint presentation from the UC Master Gardeners of Sonoma County which covers how wildfires affect soil, soil regeneration, and strategies for dealing with toxic soil.
Camp Fire Burns on the Ridge
Source: NASA/MSFC, USGS
Area Affected by Camp Fire, Aerial View
Source: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN, IGP, swisstopo, and the GIS User Community
Area Affected by Camp Fire, Relief View
Sources: National Geographic, Esri, DeLorme, HERE, UNEP-WCMC, USGS, NASA, ESA, METI, NRCAN, GEBCO, NOAA, increment P Corp.
By Alicia Springer, UC Master Gardener of Butte County, November 30, 2018
Note that our merciless summers require additional irrigation for even drought-tolerant native plants while they are getting established. A spare but regular drip-irrigation line for the first two summers will improve survival rates.
- Sedges (Carex species) and rushes (Juncus species) for sun
- Yerba buena (Clinopidium douglasii) for part-shade
Deep-rooted, larger grasses to anchor:
- Deer grass (Muhlenbergia patens)
- Native fescues (Festuca californica, F. idahoensis, F. rubrica)
- Creeping wildrye (Leymus triticoides)
Perennials that tolerate winter moist, summer dry conditions:
- Douglas iris (Iris douglasii)
- California fuchsia (Epilobium canum)
- Prostrate manzanita (Arctostaphylos uva-ursi)
- Buckwheats (Eriogonum species)
- Fleabane daisies (Erigeron species)
- Yarrow (Achillea millefolium)
- Common monkeyflower/aka sticky-monkey (Mimulus aurantiacus)
- Yellow monkeyflower/aka seep mimulus (Mimulus guttatus)
- California coneflower (Rudbeckia californica)
- Hummingbird sage (Salvia spathacea) and other salvia species
Drought-tolerant ferns for shade
- Polypody fern (Polypodium californicum)
- Western sword fern (Polystichum munitum)
- Wood fern (Dryopteris arguta)
Shrubs and small trees for banks
- Hybrid rockrose (Cistus skanbergii)
- Barberry (Berberis aka Mahonia pinnata)
- Toyon (Heteromeles arbutifolia)
- California coffeeberry (Rhamnus californica)
- Gooseberry (Ribes speciosum)
- Wood rose (Rosa gymnocarpa)
- St. Catherine's Lace (Eriogonum giganteum)
- Redbud (Cercis occidentalis)
- Mountain mahogany (Cercocarpus betuloides)
- Red twig dogwood (Cornus sericea)
- Ceanothus species
- Manzanitas (Arctostaphylos species)
For more information on gardening in our area, visit the Butte County Master Gardener web page at: http://ucanr.edu/sites/bcmg/. If you have a gardening question or problem, call our Hotline at (530) 538-720l.