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.
Photo Credits:
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.
By Cindy Weiner, UC Master Gardener of Butte Count, November 16, 2018
Eve Werner, landscape architect and owner of Eve's Garden Design, likes to use coffeeberry (Frangula californica) as a screen, background or hedgerow. Its blackish berries resemble coffee beans and are very attractive to birds. This evergreen shrub can grow to six to ten feet tall and wide although the cultivar ‘Eve Case' is smaller, only reaching about five feet. It is native to Butte County and grows in Upper Bidwell Park. Werner says, “This adaptable plant thrives in full sun to shade with monthly to no summer irrigation.”
Jason Mills, owner of Ecological Solutions, suggests, “If you're looking for an evergreen shrub, why not try giving the local and less commonly used hollyleaf redberry (Rhamnus ilicifolia) a shot?” Hollyleaf redberry has small serrated leaves, resembling holly. It grows best in full sun or partial shade. The flowers are small and inconspicuous but develop into beautiful red fruit, which provide food for birds. It grows five to ten feet tall and needs no summer water once established.
Mills and Whittlesey like using the large perennial bunch grass deergrass (Muhlenbergia rigens). Whittlesey says, “I use deergrass to bring a rhythm and flow into a garden. When in flower in later summer, it has a stronger architectural form which holds through the winter months. It combines readily in front of larger shrubs or as a foil for small shrubs and perennials.” Deergrass forms a dense clump to 4 feet tall and wide in full sun or light shade.
- Author: Alicia Springer, UC Master Gardener of Butte County
By Alicia Springer, UC Master Gardener of Butte County, November 2, 2018
Chicoans have a macro-example of this approach to storm water in our own Lindo Channel, which catches the overflow when Big Chico Creek runs high. While many towns direct excess storm water to concrete flood control culverts which whisk the water to treatment plants, Lindo Channel's runoff nourishes a riparian corridor of oaks, sycamores, willows, cottonwoods, and bay trees (along with nonnative brush). The stream flow recharges upper-level groundwater, and the greenery helps clear air pollution and offers sanctuary to birds and other animals large and small.
A swale is a shallow channel, bermed a bit on both sides, that lets gravity do the work of moving rainwater along a gently sloping course. The swale directs water away from structures and through a straight or meandering depression lined with river rock, grasses, or other vegetation that can tolerate periods of winter wet and summer dry (regional native plants generally fit the bill). A grassy, vegetative swale might be lined with cool-season native meadow grasses such as sedges (Carex species) or rushes (Juncus species) that thrive with winter moisture and go dormant over the dry summer. A rock-lined swale resembling a dry creek bed holds visual interest throughout the seasons. Water-loving plants can be sited closer to the flow, while more water-averse selections can keep their feet dry further up the banks.
In general, your rainwater collection surface should slope downward from the water source, or you can create a minimum 2% slope. Steep slopes can create erosion, so avoid orienting your swale down slope in such areas.
Locate your swale:
- At least five feet away from structures without a basement, or ten feet from structures with a basement.
- Away from septic systems and leach fields
- Away from a tree's crown or major root zone to avoid root rot
- In full or partial sunlight to support plantings
Anchor your artificial creek bed with larger stones, boulders, and deep-rooted plants such as deer grass (Muhenbergia rigens) and fescues (Festuca species). If space permits, larger shrubs can create a more dramatically varied look. Vegetation should be planted and at least partly established before the winter storms, so be prepared to irrigate in dry periods and through at least the first summer. Once well established, deep-rooted native plants will enjoy the cool season storm water and survive the summer heat.
From a simple gravel channel to a dry creek to a more elaborate retention pond, the hardscape elements of a rain garden project may seem daunting without step-by-step instruction. “Coastal California Rain Gardens” published by University of California Agriculture and Natural Resources (UCANR), offers detailed information about planning, building, and maintaining a rain garden. Another useful guide is “Slow it, Spread it, Sink it! Rain Gardens and Swales” published by the Napa County Resource Conservation District. Both publications offer additional plant suggestions and resource listings.
Additional information and plant names used in photos:
A dry creek rain swale in a suburban garden landscape. The swale, roughly 50 feet long x 10 feet wide, runs along a sloping driveway. Redbud (Cercis occidentalis), deergrass (Muhlenbergia rigens), St. Catherine's Lace (a buckwheat, Eriogonum giganteum), Santa Barbara daisy (Erigeron karvinskianus) and California fuchsia (Epilobium canum) are among the native species seen.
Plants that tolerate winter moisture and summer drought line the banks of the swale. Idaho fescue (Festuca idahoensis) and California fuchsia (Epilobium canum) are seen. A redwood (Sequoia sempervirens) is on a raised bank so rainwater can irrigate but not saturate the root area. The redwood will require summer watering to stay healthy in the Butte County climate unless it's near a perennial stream.
A decorative rain chain at the ‘headwaters' of the creek bed directs flow from the roof gutter. Note that the creek bed is directed away from the base of the redwood, which is on a higher bank.
Boulders and deergrass (Muhlenbergia rigens) stabilize the slope and provide pleasing visual variety. Larger native plant selections screen the property. These include toyon (Heteromeles arbutifolia), mountain mahogany (Cercocarpus betuloides), deer grass, and redbud (Cercis occidentalis).
Diagram of a grass-lined vegetative swale courtesy of Napa County Resource Conservation District.
By Jeff Oster, UC Master Gardener of Butte County, October 19, 2018
Echinacea is a tough perennial with brownish orange dome-shaped centers. E. purpurea (purple coneflower) can reach four or more feet in height and form a dense clump two feet wide. The four-inch flowers have purple ray flowers (petals) that droop downward. Situated in sun or part shade, these plants have a long blooming period, from June through August. They require well-drained soil and moderate to regular watering. Coneflowers require little in the way of maintenance other than dividing when they become overcrowded (about every four years). When dividing and re-planting, make sure each division has a shoot and roots. Coneflowers are self-seeders, and will multiply if happy. They attract bees, birds and butterflies; if the flowers are left on the plants, their bristly seed heads provide birds with food during the winter. Deer will eat the young plants but generally avoid mature ones. Coneflowers make good cut flowers and can be dried and preserved.
The edible flowers of Mexican marigold can be added to salads; the narrow, dark-green leaves have a strong scent and can be used as a substitute for tarragon; and the dried leaves and flower heads can be used to brew a pleasant anise-flavored tea. This plant attracts butterflies, bees, and birds to the garden, and is generally not bothered by pests.
Apply one inch of water every week during spring and summer to the base of the plant. Pinch one inch from stem tips to promote bushy growth and flower production throughout the season. Stake tall plants to keep the clump upright. Cut back after flowering. Propagate from rhizomes or seeds. The flowers of Helianthus maximiliani can be cut to bring inside; they also dry well. Young growth on these plants is attractive to slugs, but rabbits and deer steer clear. Native Americans traditionally utilized these plants for food, dye, oil, thread, and to repel mosquitoes. Butterflies and bees gather the pollen and songbirds love the abundant seeds.
The UC Master Gardeners of Butte County are holding a Plant Sale on October 27 at their Demonstration Garden at Patrick Ranch (10381 Midway, Durham). All plants have been propagated by UC Master Gardeners of Butte County and selected to thrive in our climate. Check or cash only—no credit cards. For more information on the Plant Sale, including Workshops beginning that day at 9 am and a list of plants for sale, go to https://ucanr.edu/sites/bcmg/sale/
HOTLINE – Questions? Plant problems? Pest Issues? Contact the UC Master Gardeners of Butte County by phoning our Hotline (530-538-7201), or visit our web page at: http://ucanr.edu/sites/bcmg/