Category Archives: California drought

Trees Help offset rising CO2 levels

Never underestimate the power of nature especially that of plants. I was heartened this week to read about a study recently published by the Department of Energy’s Lawrence Berkeley Laboratory regarding the increased rate that the earth’s vegetation is absorbing human-induced CO2.

OLYMPUS DIGITAL CAMERASanta Cruz Mountains looking towards Monterey Bay

When I was a kid my father used to work at the Berkeley Lab. As a welder during the 50’s I remember him coming home and tell me about working on the bevatron which was the state of the art atom-smasher being built there. The goal of Berkeley Lab which Dad used to call The Radiation Lab has always been to bring science solutions to the world.

A new study published in this month’s Berkeley Lab newsletter, has found that plants are grabbing more carbon from the air than in previous decades. The study is based on extensive ground and atmospheric observations, satellite measurements of vegetation and computer modeling.

“To be clear, human activity continues to emit increasing amounts of carbon”, the study explains but plants have slowed the rate of increase in the atmosphere by absorbing more. “It’s a kind of snowball effect: as the carbon levels rise in the atmosphere, photosynthesis activity flourishes and plant take in more carbon, sparking more plant growth, more photosynthesis and more carbon uptake.”

Another player was identified in the study. Plant respiration, a process in which plants use oxygen and produce CO2, did not increase as quickly as photosynthesis in recent years. This is because plant respiration is sensitive to temperature. The study showed that between 2002 and 2014, plants took in more CO2 through photosynthesis but did not “exhale’ more CO2 into the atmosphere through respiration.

We what does this all mean? “This highlights the need to identify and protect ecosystems where the carbon sink is growing rapidly,” says Trevor Keenan, a research scientist and author of the paper. “Unfortunately, this increase in the carbon sink is nowhere near enough to stop climate change. We don’t know where the carbon sink is increasing the most, how long this increase will last, or what it means for the future of Earth’s climate.”

Still I’m hopeful that the earth will heal itself if given the chance and we can thank plants including the humble houseplant for helping offset increasing levels of CO2 from fossil fuel emissions.

Berkeley Lab is at the forefront of research in the world of science. Earlier this month they hosted a three day forum to study and share information about how plants transport water from their roots up through the stem and how they respond to stress such as drought. The new data will provide insight about how to better tend crops and other plants under stress and to improved understanding and forecasting for drought-related die-offs of trees and other plant species.

Also in the news at Berkeley Lab is the research the lab is doing in the search for an Ebola cure. Rather than using human or lab animals, a crystal isolated from the cells of a broccoli related plant called mouse-ear cress, provided the target related protein. Researchers have used this plant as a model species for studying cell activities and genetics since the mid-1940’s and in 2000 this plant’s genome was the very first plant genome to be sequenced. Quite an honor for another humble plant.

Let us be thankful for the plants we all love so much.

Succulents: One Solution for the New California Garden

According to Weather West, a California weather blog authored by climate scientist, Daniel Swain, the latest seasonal predictions do not inspire a great deal of hope that the coming winter will bring drought relief. “A substantial La Nina event no longer appears to be in the cards. If it’s present at all, it will probably be quite weak.” Seems that persistent West Coast winter ridge may just rear its ugly head again. Even if subtle shifts in the large-scale atmosphere pattern lead to a different outcome here, our persistent drought is still on the table.

aeonium_sunburst_staticeAeonium ‘Sunburst’ with statice limonium perezii

More and more people are asking me to update their landscaping to use less water and be lower maintenance. Many want a more modern look and what could be more architectural and clean looking than a succulent garden?

Converting to a low water landscape requires careful planning and design to achieve the look you want. You need to evaluate drainage patterns, soil types, slopes, areas of sun and shade and building locations. Hardscape features, such as patios, paths and decks require no water to maintain and by selecting permeable materials such as porous pavers and gravel, rainwater can infiltrate the ground. Large boulders can be used as accents.

Next comes the fun part- plant selection. In choosing the best succulents for your garden think about if your area gets frost during the winter. Does it have protection from a building or evergreen tree or do you live in a banana belt that rarely freezes? Are you planting in sun, shade or a combination?

In addition to the hardy succulents like sedum and sempervivum many showy succulents need only a bit of protection during our winters. Aeonium decorum ‘Sunburst’ is one of the showiest species with spectacular variegated cream and green 10″ rosettes. It looks terrific planted with black Voodoo aeonium. Aeoniums do well in our climate as they come from Arabia, East Africa and the Canary Islands where winter rainfall is the norm.

echeveria_lace-closeupEcheveria ‘Lace’

Echeveria grow naturally in higher elevations of central Mexico to northwestern South America and so also do well in our our cool wet winters. ‘After Glow’ is frost tolerant and looks to be painted with florescent paint. There are spectacular hybrids being developed every year. These are not as hardy as the traditional hens and chicks but well worth the effort to find a place where they can survive a freeze. Frilly ‘Mauna Loa’ sports turquoise and burgundy foliage while Blue Curls echeveria looks like an anemone in a tide pool.

OLYMPUS DIGITAL CAMERASucculent selections

Aloes from South Africa and Arabia are old world plants. Many, like the medicinal aloe vera, are frost tender, but other such as the tree-like aloe plicitilis are hardy down to 25 degrees and look great either in the garden or in pots. Did you know the Egyptians used aloe in the mummification process or that there are no known wild populations of aloe? In South Africa an aloe called ferox is used in the same way as aloe vera for burns and stomach problems.

To ensure success when growing succulents, make sure your soil is fast draining. Our winter rains can rot even the toughest plants when their feet sit in soggy soil. Add sand, gravel or pumice to your soil or plant on mounds to increase drainage.

How to Save Water & Have a Beautiful Garden

There was enough rainfall over the winter season for the California State Water Resources Control Board to modify their Emergency Water Conservation Regulations. On May 18th, 2016 it was adopted to recognize persistent yet less severe drought conditions throughout California and require local agencies to develop and implement conservation standards based on their particular circumstances.

Adelyn_ wateringMy friend, Adelyn, helping to water container plants and edibles.

The new standard requires local water agencies to ensure a three-year supply of water assuming three more dry years in the future like the ones we experienced from 2012 to 2015. Water agencies that would face shortages under three additional dry years are required to meet a conservation standard equal to the amount of the shortage.

Makes sense to us who have long been on the band wagon to conserve water both indoors and out. Our local water districts have both kept their water conserving restrictions in place. Since up to 70% of summer water use comes from landscape irrigation it’s a good place to start.

Both San Lorenzo Valley Water District http://www.slvwd.com – and Scotts Valley Water Districts http://www.svwd.orgoffer many tips and incentives to conserve water. Using less water-intensive plants, there are lists on their websites of drought-tolerant plants and water smart grasses, as well as replacing lawns with drought tolerant or native plants and/or permeable landscape materials such as mulch, decomposed granite, permeable pavers are just some of the ways you can keep your yard looking beautiful and also be water efficient.

Rainbird_Smart_Irrigation_ControllerRainbird Smart Irrigation controller

Rebate programs from local water districts offer several landscaping credits including sprinkler to drip irrigation conversion credit, weather-based irrigation controller credit, replacement credit for converting an existing lawn to water-wise grasses, greywater laundry-to-landscape irrigation conversion, rainwater catchment and downspout diversion. Both districts have guidelines and procedures to apply for the rebates on their websites.

Additional rebates from the California State Department of Water Resources are available to single-family residences for lawn replacement. This rebate application is separate from the local water District’s and you need to go online and follow the state’s guidelines in order to be eligible for these additional funds. See www.SaveOurWaterRebates.com for the details.

aeonium_echeveria_statice_agapanthusPlants with similar water needs = hydrozoning

The fun part begins when you redesign the area where you took out the lawn or modify the plantings in other beds to include same water use plants. It doesn’t make much sense if you have some plants that require more water than the others in the same bed. You have to water to the highest water use plant to keep everybody happy.

Hydrozoning is the practice of clustering together plants with similar water requirements to conserve water. A planting design where plants are grouped by water needs improves efficiency and plant health by avoiding overwatering or underwatering. As you move farther away from the water source your plantings should require less water.

Now is the time before it gets hot to look at your irrigation system, plant choices and rebate options to save water and money and recharge our aquifers.

Dry River Beds – Beautiful & Beneficial

dry_river_bed1Dry river bed down a steep slope

With so many people replacing their thirsty lawns with low water-use plants, I’m getting lots of requests for ideas about what to do with all that empty space. The sky’s the limit when you have a blank slate. Let me get you started.

If your old lawn was in the front you might consider putting in a sitting area for a couple of chairs and a bistro table. Use simple crushed gravel or more formal flagstone underfoot and surround the space with a low seat wall to add a bit of privacy.

Adding a dry river bed is another good solution. A dry river bed can slow runoff, spread it out and sink it back into the soil. Connected to a downspout they keep even more rainfall on your own property. If we get the El Nino storms that are predicted this will be a welcome addition to your landscape.

A dry river bed is a rock-lined swale that uses rounded river rock in addition to vegetation to allow

OLYMPUS DIGITAL CAMERADry river bed with grasses and deer resistant oleander

runoff to soak into the ground. Make sure there is a 2% slope from beginning to end to ensure that water is conveyed away from your house to the desired location. Non-woven geotextile fabric is often used underneath the rock.

You can create a depression or rain garden at the end of your dry river bed and plant it with plants that tolerate wet feet in the winter. Both a dry river bed and a rain garden allow water to sink back into the ground. The plants remove pollutants from the runoff from roofs or other impervious surfaces.

A rain garden might be a simple, shallow depression filled with plants that can flourish in both moist and dry conditions. The size and depth will depend on your how much water you need to capture in a winter runoff

Sometimes a dry river bed will receive so much runoff that a dry well or dispersal pit is installed at the end. If you have a high water table or clay soil the water may not always soak in fast enough and an overflow device like this is needed. The goal is to keep water on your own property and not in the street or the neighbors’ yard.

There are good looking dry river beds as we’ll as bad looking ones. A quick Google image search will show you what I mean. Your goal is to create something that looks like it belongs right where it is. The plants, the accent rocks, the cobble, the location – all need to work together.

If your property has a natural slope follow the natural terrain if possible. You can install a dry river bed on flat land also by creating a channel for the river bed to follow. Keep in mind that even a dry river bed is more interesting if it is not all visible at once. Soft, flowing curves and bends create a natural look.

Start with the rocks and cobble. Rounded river cobble looks most natural for the creek bed. In nature, water flowing down a river would round off sharp rock edges to produce cobble of different sizes. A river never has just one size of rocks and yours shouldn’t either.

Accent rocks can be any type that you like as long as you get a variety of rock sizes and shapes. Use the larger stones to direct and channel water. Placing rocks on the outside of a curve creates a more natural look.

OLYMPUS DIGITAL CAMERAPheasant Tail grass along cobble path

As in all gardens there is always a bit of maintenance to keep things looking and working great. Weeding in the first couple of months while plants become established is important. Replenish mulch as needed until the plants grow in.

Periodically remove leaves that have landed in your river bed and reposition rocks moved by runoff to keep your dry creek bed working for you when you need it. Also don’t start your dry creek bed too close to the foundation of your home if that area is flat. You can direct the water through a drain pipe connected to a downspout to a lower starting spot in your garden.

So whether you are adding a dry river bed to add interest to your lawn-free landscape or to double as catchment for winter storm runoff, make yours look like it’s always been there.

Save Water – Save Trees

I had to do it. I couldn’t resist. Even though I’d vowed not to get any new plants until fall planting season when I saw the one gallon Pride of Madeira just begging for a new home I succumbed to my impulse. I rationalized this plant was on my wish list and will be drought tolerant so I wasn’t being totally irresponsible.

I’ve always wanted an echium fastuosum on my hillside. I admire those huge spires of purple-blue flowers whenever I see them in other gardens. These are tough plants getting by with no summer water once established and the flower spikes are bee magnets. I covered it with a layer of shade cloth for a few days because it was so hot when I planted it. This will help it establish more quickly while the roots take hold in the soil.

Flame_treeFlame tree on Stanford campus

In your own garden it’s wise to establish a drought to-do list. I’m talking about what plants get your precious water and what to let go.

As we enter another dry year many of our ornamental and fruit trees are dying. Many were watered along with the lawn you have now let go brown. Others might have been surviving on natural rainfall. Whatever the case in your garden don’t let your trees die.

Nature has already killed an estimated 12 million trees in Calif. forests since the drought began four years ago. Most of these have fallen victim to bark beetles that attack trees weakened by drought.

In our own neighborhoods, trees are a long-lived asset. A tree is not something that can be easily replaced. It’s OK to appropriately water trees. Dying trees can be a safety hazard and removing a dead tree is expensive.

It takes years to grow a tree to mature size. Save and use shower and cooking water to help them out. Maybe it’s time to install an simple laundry-to-landscape system to water your landscape trees. Or set up a separate drip or soaker hose for your trees and give them a good deep drink at least once or twice a month. And remember that the tree’s feeder roots are not at the base of the trunk but out at the drip line and a little beyond.

laurel tree.1600Laurel tree on Stanford campus

A rule of thumb for determining when to irrigate is when 50% of the water has been depleted from the soil in the plants’ root zone. This allows a buffer of water in the soil in case the weather suddenly turns hot and windy and applies to trees, shrubs and perennials.

Sandy soils hold less water than clay soils and must be irrigated more frequently. A common misconception is that it takes more water to grow plants in sandy soil than in clay soil. Actually the total amount required for the whole year is the same for both soil types. The amount of sunlight, wind, temperature and humidity control how much water a plants needs – the soil is only the reservoir.

To check the water content in the soil dig 8-16 inches down into the soil with a trowel, shovel or soil tube and feel the soil. At about 50% available water:
* Course soil appears almost dry and forms a ball that does not hold shape.
* Loamy soil forms a dark ball that is somewhat moldable and can form a weak ribbon when squeezed
between the finders.
* Clayey soil forms a good, dark ball and makes a ribbon an inch or so long and slightly sticky.

If you are planning to plant some new trees this fall, be sure they are drought tolerant natives or low water use non-natives. There are many nice specimens to choose from. And don’t skimp on the mulch.

It’s important to maintain our existing tree canopy and plant for the future. Even in times of drought, no especially in drought, planting and stewardship of trees is critical. Not just for their future but for ours as well.

Tips for New Landscaping after Replacing a Lawn

OLYMPUS DIGITAL CAMERAsantonlina, euphorbia, phormiun – low water use plant grouping

Tired of looking at that brown patch of lawn and trying to convince yourself it’s a badge of honor in these times of drought? You tell yourself “It greens up in the winter so I’ll water just enough to keep it from totally dying now”. But wouldn’t a beautiful, sustainable, low water use garden be a more inviting place to spend your free time?

Replacing a lawn that is not used anymore can be the first step in a whole new kind of landscaping-a landscape that looks like it belongs where you live. Here are some very good reasons to lose the lawn and benefit the planet at the same time.

Even in years where we have normal winter rainfall we always have a seasonal drought. It’s called summer. Without our usual winter and spring rains, though, even native trees and shrubs are struggling. All the more reason that plant selection now is even more critical than before.

libertia2.1600libertia peregrinans

You’ve see pictures of some not-so-great looking lawn replacement projects. A drought tolerant plant here, another there, add an accent rock and that’s supposed to thrill you when you come home for the day? What’s missing is a garden designed to enhance our natural environment. When you remove your lawn, it’s a wonderful opportunity to not only create a garden than conserves water but also provides habitat for wildlife including birds and butterflies and improves the soil.

A living landscape does as much for our own pleasure as it does for the environment. It increases biodiversity of plant, animal and insect populations. It fosters healthy soil which can hold more moisture by supporting microbes and insects. Healthy soil can filter pollutants and improve water quality.

Think of using native and well-adapted, non-natives that connect with the natural landscape. Use tough plants on the edges and group greener, low water use plants closer to the house. Here are some good plants to use in a lawn-less landscape that won’t break your water budget.

When planting time rolls around this fall consider a green carpet of blue grama grass. This native sedge can provide a green carpet on much less water and can be mowed or not. It’s on the list of approved water-wise grasses eligible for rebates from our local water districts.

dymondia_path2.1600dymondia groundcover between flagstones

Another ground cover eligible for lawn replacement rebate is dymondia. I love the grey foliage of this low ground cover. It fills in nicely between stepping stones or can take light foot traffic in larger areas.

For a taller look that you don’t need to be able to walk on, the ground cover forms of ceanothus, manzanita or creeping rosemary are good very low water alternatives to a lawn. I have a very low Hearts Desire ceanothus that hasn’t been watered yet this year and it still looks green and lush.

Native yarrow, penstemon and salvia are the work horses of the garden needing little water once established and attracting all sorts of insects and birds. Other natives on the 800+ Approved Low Water Use Plant list include Pacific Coast iris, helianthemum, libertia, santolina, California fuchsia, rockrose, lavender, myoporum, coffeeberry, teucrium, verbena and kangaroo paw to name just a few. You can download the list from www.sv.org or www.slvwd.com.

I am not a big fan of artificial lawns. They do not provide habitat for wildlife, beautify our environment or improve the soil. They get significantly hotter than the surrounding air temperature contributing to the heat island effect by increasing air temperatures. Also artificial turf is a synthetic material with a relatively short lifespan ranging from 10-20 years and will eventually end up in a landfill. They can not be recycled. There are many other beautiful, low water use options that result in more sustainable and beneficial landscapes.

Water and soil management as well as plant selection are key to water conservation in the landscape.