Special thanks to Lindsey Zero of Silver Leaf Landscapes for joining us for this month’s discussion on landscaping pro tips in the Santa Barbara area, following the Thomas Fire and Montecito Mudslide.
Part 1 of 3 – landscape damage assessment
Part 2 of 3 – landscape erosion control
Part 3 of 3 – landscape plant selection
Landscape Damage Assessment
1. Look For Hazards – example: broken pipes or wood, unstable rubble piles, undercut walkways or hillsides, leaning or broken trees. Mark location of hazards on your property so they can be addressed in the future.
If any hazards are threatening your property or preventing safe access, these should be addressed first. Create a zone on your property with easy vehicle access to stockpile debris. This will help speed up the removal process later.
2. Assess What Can Be Saved
Focus efforts on saving high value landscape specimens, especially trees and mature hedging.
Steps to begin:
1. CALL 811 (CA underground service alert) BEFORE DIGGING! Plan ahead, as you will have to wait a few days for the utility company to mark the location of all underground utilities.
2. Moisten soil around plant trunks (if not already moist, of course) to soften deposits. Soil should be moist but not muddy. Plan ahead! Moisten soil a day before you start digging so you’re not working in a muddy mess.
3. Carefully remove soil with hand tools, being careful not to damage trunks.
4. Remove soil deposits down to beginning of tree root flare, in ring around trunk.
5. After removing soil directly against the trunk, you can use machinery to remove deposits, but be careful! Driving heavy machinery over wet soil can easily damage the soil structure and harm the plants you’re trying to save!
6. Remove as much soil as possible from below the canopy of mature trees. This area is called the CRZ, or critical root zone.
7. On trees without a wide canopy, measure the trunk diameter in inches, and then multiply that number by 1.25 or 1.5 to get a rough idea in feet of how far the roots extend outward from the trunk base.
8. Small shrubs, perennials & lawns still covered by debris at this point will likely not be worth saving, unless they are minimally covered by soil deposits and can be washed clean. Work with your landscape professional to make an accurate assessment of your particular site!
Mud flows may have settled into a hard rock-like state. Such soils may need to be mechanically tilled or worked with machinery to become usable for new landscape plantings in the short term.
What should I do with all the soil deposits on my property?
If you have minimal deposits, carefully remove any debris and stockpile the soil to create new topography later!
What should I do if I have A LOT of deposits on my property, or don’t have a good place for the soil?
Work with your neighbors w/ large lots to see if they would be interested in having additional fill soil!
What should I do to get ready for the next rainfall event?
Focus on keeping water on your site so it doesn’t run off downstream! We’ll talk about this next.
Like with damage assessment, you want to start with observation. How will water move through your site? Generally, you want water to stay where it falls! So when trying to control erosion, start at the top of your landscape to spread and slow the water as it moves downhill.
1. If your land has a gentle slope of up to 3:1 (3 units horizontal to 1 unit vertical), consider adding features to spread and slow the water! But first you need to mark the topography of your land! Use an A-frame or water level to mark out where the contour lines run along the ground.
2. Once you’ve marked out the contours to determine the slope of your land, you can better determine what actions
a. No slope, or nearly flat? Create shallow basins w/ mulch & vegetation.
b. A little slope, up to 3:1? Create berms and basins w/ vegetation.
c. More slope, 3:1 or greater? Terraces and/or vegetation.
3. What materials can I use to control erosion on gentle slopes? A variety of material can be placed parallel to contour lines to slow and spread the water as it moves downhill perpendicular to your contour lines. These include: logs, brush, woodchips, coir (coconut) fiber wattles, rock or rubble, and especially soil! Avoid plastic sheeting, straw, and jute netting, as these do little to help water sink into the ground. I always recommend people start small so they can test out different techniques and see what works.
Where should I put my erosion control features?
Start at the top of your slope and place berms where water energy is the lowest! Keep features at least 10 feet away from structures, and be sure you’re directing water away from structures!
Remember, these basic techniques are not meant to be used in active or ephemeral waterways. If you have water actively flowing through your site, you may want to work with a landscape professional or engineer to determine an appropriate solution.
What happens if the first berm overflows?
Plan an exit for the water! Locate an exit at a strategic point along a contour berm to send water downhill to the next berm, or be sure one end is lower than the center of your fishscale berm, so water can spill out to the next feature.
What about mulch?
Yes, please mulch! Remember, mulch can be washed away by water flowing down a steep hillside, so be sure any water flowing down a slope has been slowed by your erosion control features. The best value is Santa Barbara County’s unscreened mulch, which they will deliver to your site with a week or so lead time. Last time I saw it, the mulch was pretty nice looking too!
What about mulch in high fire zones?
Recycled wood mulch has been shown to have the lowest incident of ignition compared to other organic mulches (including rubber/plastic mulches), and helps make your landscape be more fire resistant by reducing soil temperatures, which keeps more water in the soil and encourages plants to maintain a higher water content in their leaves. Gravel mulches can also be useful in certain landscapes. Work with your landscape professional to install the right mulch for your landscape!
What if I have really steep slopes?
Unless you have a reason to be on such a slope and want to build terracing, let it go develop a beautiful cover of fire-wise vegetation!
A Few Plant Selections
There are many hundreds of plants available in the nursery trade and every project may need something different! However, I’m going to give a three plant suggestions today that are specifically useful for erosion control on the Santa Barbara coast. These plants are native to the area or regionally adapted, are beneficial to wildlife, and look great!
Ceanothus ‘Yankee Point’ – A great, large scale ground cover California Lilac with glossy green leaves and bright blue flowers. Grows fast to 10′ wide, sometimes larger! One of my favorites for a refined look, provides a nice clean background to show off other plants.
Baccharis ‘Pigeon Point’ – Dwarf Coyote Brush
This is the winner for erosion control on a hillside where nothing seems to want to grow! Stays low and green year round while providing benefits to local birds and wildlife. Not super showy, but for a plant that is bright green year-round without a drop of water after establishment, it’s a winner.
Salvia ‘Mrs Beard’ | Salvia ‘Dara’s Choice’ | Salvia ‘Bee’s Bliss’ – Creeping Sage
All three of these sage varieties are great low growing groundcovers for large sloped areas! Will attract bees, butterflies and hummingbirds in the summer and smell wonderfully fresh year round.
I need more help! What can I do?
1. First, I always recommend that my clients make a priority list for their landscapes that are in need of improvement. What do you want to do or see in the landscape? What are most important features you’d like? Rank them!
2. Consider creating landscapes that require few resource inputs (like time, water, fertilizer & maintenance) but deliver big benefits!
3. Work with landscape professionals to develop your new landscape! Visit the Santa Barbara Contractors Association website to find local, licensed contractors to help with your next project.