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.

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Santa 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.

A Thanksgiving Poem for the Santa Cruz Mountains

pumpkin_and_mumsA Thanksgiving Poem  by Jan Nelson,  The Mountain Gardener

Once upon a time when our area was under the sea
there were no parks or trails or trees or gardens.
I’m thankful that our mountains rose from an ancient ocean
and we can now enjoy this beautiful place we call home.

I’m thankful for the bigleaf maples with leaves as big as saucers
and for the giant redwoods that sprouted long ago
and the five-fingered ferns that grow lush
along Fall Creek on the way to the old lime kilns.

I’m thankful for the pond and western turtles who live at Quail Hollow
and for the unique sandhills, grasslands and redwoods
and for the western bluebirds and other creatures that call it home.

I’m thankful for the dog park and soccer field at Skypark
where little kids and dogs both big and small have a place of their own
and for the picnic area and Fourth of July fireworks,
and the Art and Wine festival and Music in the Park on summer nights.

I’m thankful also for all our parks from Garrahan, Junction, Highlands,
Fall Creek, Henry Cowell and Felton Covered Bridge in San Lorenzo Valley,
to Lodato, Siltanen and MacDorsa parks in Scotts Valley.
Each place is unique and is each one of us.

I’m thankful for Bonny Doon where I can see both sides of Ben Lomond Mountain
and for the Ecological Reserve with its fossilized marine animals and sharks teeth
that are exposed in the mountain made of sand.

I’m thankful for California’s oldest state park. Big Basin, with its waterfalls and lush canyons
and slopes covered with redwoods sorrel, violets, fragrant azaleas and mountain iris
and for the banana slugs, marbled murrelets and red-legged frogs who make it their home.

I’m thankful for the whisper of the wind blowing across the water at Loch Lomond
and for the gentle whir of fishing reels along the bank,
thick with tan oaks, redwoods and madrone.

And finally, I’m thankful for friends, family and neighbors
who share the knowledge that in nature life continues.
Look around you and be thankful for the bounty, the restfulness,
and take time to enjoy these beautiful mountains that we call home.

I wish you all a Happy Thanksgiving.

November Tasks in the Santa Cruz Mountain Garden

Outside my window, the Forest Pansy redbud has started to display its spectacular orange fall color. There’s a suet feeder hanging from the branches so I get to enjoy the antics of the Pygmy Nuthatches, Purple Finches and the Chestnut-backed Chickadees all day long as I watch the changing colors of the foliage. Other than watch the birds and the changing foliage colors what should I be doing out there in the garden?

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Hedge parsley aka Torilis arvensis

Light weeding is easy now that the soil is soft and moist. The dreaded hedge parsley has germinated early with our October rains. With it’s spiny-ball seeds that stick to your dog’s fur and your socks it is not welcome on my property.  It’s invasive and a native of Europe. They’ll be easy to pull now.

Maybe I will plant a few more bulbs. The ground is cooling and there’s still plenty of time for them to receive adequate winter chilling. Come spring I’ll be happy I did.

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California poppies

I just planted wildflower seeds on my hillside. I hoping for more California poppies. I see some of last year’s wildflowers have reseeded. Nature knows when the time is right. I spread the new seeds in swaths and worked them very lightly into the soil, first hoeing off some early weeds that would compete with them.

What not to do in the garden now? I don’t need to prune trees and shrubs at this time of year. Other than clipping a few well placed branches to use for holiday decorations, I’m off the hook for this task. Deciduous trees are still in the process of losing their leaves and are not fully dormant. Evergreen shrubs and conifers can be trimmed lightly but most shaping is done when they start growing in late winter or very early spring. Fall is not a good time to prune. Wounds heal slowly, leaving them more susceptible to disease. As a general rule, don’t prune when leaves are falling or forming. To avoid sap flow on birches and maples prune after leaves mature next year.

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Japanese Forest grass in winter

The growing season is pretty much over for me except to enjoy what’s left of fall color and the ornamental grasses waving their seed heads in the wind. A lot of perennials are dying back but I’m not in a hurry to neaten things up. The seed heads left in the garden supply food for birds and other creatures while the foliage provides shelter for the plant in the cold and frost. Remove anything that has turned slimy or just plain unattractive but leave berries and seed heads for food and winter interest.

At this time of year my garden is visited also by Lesser goldfinches and warblers who will spend the winter and I’m doing them a big favor by not cutting back brown foliage containing nutrient-rich seed heads. Some of the reliable seed producers that I won’t have to clean up this weekend include artemisia, aster, coreopsis, penstemon, sedum, lupine, salvia, black-eye Susan, coneflower, phlomis, monarda, agapanthus and grasses.

Used to be the first frost in our area came about the first or second week of November but not anymore. Be prepared whenever it comes by moving frost tender plants under overhangs if possible or having frost blankets ready to cover frost tender plants.

Finding Fall Color in the Santa Cruz Mountains

The beginning of fall really started for me with those drenching October rains. Night time comes early now as daylight savings time ended last Sunday. Our fall color foliage trees and shrubs are starting to turn color. Will they be as vivid this year? Although we don’t get as much fall color as other areas we enjoy what we have just as much. Besides we don’t get snow on Halloween. Enjoy these cool nights and warm days. That’s the combination that brings on the best fall colors.

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Japanese maple showing fall color

The vivid colors in a leaf are always there. They are just masked by the green chlorophyll which is busy making food by photosynthesis while the sun shines.

Come autumn, shorter days and cooler temperatures cause the trees to switch into energy-storage mode and their leaves stop producing chlorophyll. For the few weeks before the leave fall to the ground, they are colored only by their natural pigments. It’s these colors – red and purple anthocyanins, yellow and orange carotenoids – that make fall foliage so glorious, sometimes anyway.

Weather conditions play a major part in fall color. Some years the show is more dramatic than others. The best conditions for intense leaf color to develop are dry sunny days followed by cool, but not freezing, nights.

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Quaking aspen in Wyoming

A warm, wet autumn will almost surely result in less-than-spectacular foliage because the process of chlorophyll loss will be less consistent. Freezing temperature meanwhile can cause leaves to drop suddenly denying the opportunity to enter a slow, colorful dormancy.

Which plants put on the best show in our area? Here are some of my favorites.

California native Western redbud turns yellow or red in the fall if conditions allow. This plant is truly a four-season plant starting in spring with magenta flowers, then leafing out with apple green heart shaped leaves. Colorful seed pods give way to fall color. This small native tree or large shrub does well as a patio tree in gardens with good drainage.

Other California native plants like Western dogwood, Spicebush and Western azalea turn yellow, red or gold in the fall. A native vine that lights up with the onset of autumn is Rogers Red California grape. If you have an arbor, wall or fence that needs covering quickly this is your plant. The green and gray leaves are transformed in autumn into great draperies of rich, scarlet red leaves with clusters of summer fruit turning all shades of purple.

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Japanese maples on author’s patio

Trees and shrubs that also provide fall color include Eastern dogwood, Chinese flame tree, Ginkgo, Idaho locust, Chinese Tallow, Chinese pistache, crape myrtle, smokebush, witch hazel, all maples, liquidambar, katsura, Eastern redbud, sumac, crabapple, goldenrain, locust, oak leaf hydrangea and barberries.

Edibles that turn color in the fall include blueberries, pomegranate and persimmons.

Light up your garden as the light fades and the days shorten. Now through late fall is a good time to shop for plants that change colors because you can see in person just what shade of crimson, orange, scarlet or gold they will be.

Pruning Ornamental Grasses

Who doesn’t love a garden filled with the movement and beauty of ornamental grasses especially during the fall? But how do you take care of them after the show is over for the season?

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Lomandra and NZ flax in mixed planting

When I recently received an email asking what to do with an ornamental grass that had already turned that soft tawny color I figured it was time to brush up on how to care for them. To prune or not to prune? That is the question.

Grasses are distinguished from other plant families by their growth habit. They grow upward from the base of a leaf or shoot and can regrow from the crown when cut back. True grasses generally have extensive root systems which help control erosion. There are other grass-like plants like chondropetalum, New Zealand flax, kangaroo paw and lomandra that resemble grasses in their growth habits and are often some of the best companions for interplanting with grasses.

Most grasses require little care, minimal fertilizer and only occasional grooming. Some flourish with just enough water to meet their needs while others need regular irrigation. Diseases and insect pests are rare and they are not attractive to deer. They have succeeded because of their adaptability and have evolved to suit almost every environment and climate on earth.

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Japanese Blood grass – small and goes dormant

Basically, grasses and grass-like plants fall into 4 different pruning types: Large or small types that go dormant and large or small types that stay evergreen.

Large grasses that go dormant such as miscanthus and calamagrostis are pruned yearly in late fall to late winter. It’s best to hold off on pruning as long as possible to preserve the winter interest and to provide food for birds. When they turn brown and start shedding it’s time to prune. Gather the blades together with a bungee cord or rope and cut down to 10 inches.

Small grasses that go dormant such as Japanese blood grass or fountain grass should be pruned yearly at the same time. Don’t cut them too close to the crown or you risk losing a few clumps. Cut those under 3 feet tall down to 3 inches and those that grow taller down to 6 inches.

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The Guardsman- NZ flax large & stays evergreen

Large, evergreen grass-like flax and cordyline can be pruned anytime to cleanup and resize but rejuvenation should be done mid-spring. When pruning to freshen up the foliage, select the most damaged leaves and cut them out at the base. If your plant is overgrown or suffered winter damage, prune severely in mid-spring cutting off all the foliage at the base. Tall cordyline varieties can be cut off a few feet from the ground and they will re-sprout below the cut or from the base.

Lastly, small evergreen grasses like carex, acorus, blue oat grass and blue fescue grass can be cleaned up in spring by putting on rubber gloves and combing through the grass. If this kind of cleanup isn’t enough you can reduce the height by two-thirds and in a couple of months they will look good again.

When Rainfall Causes Problems

If you were waiting for some rain before planting to control erosion wait no more. That last storm brought plenty of the wet stuff and the next round is hopefully not far off. You’ve gotten a reminder of those areas that need stabilization during the rainy season.

Fall is the perfect time to start planning and planting. The nights are cooler, the days shorter and the soil still warm. Everything that a new plant needs to get a good start.

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Steep hillside at author’s house covered with erosion control plantings

Using the right plants on hillsides can help slow, spread runoff and prevent soil erosion. Often they need to adapt to shallow, poor soil and cope with less than ideal conditions all while putting down dense, strong roots. Mulch also protects soil from direct rain impact and slows runoff across bare soils. This is important while new plants are growing in. Covering the steepest slopes with jute netting through which plants may be installed is an added precaution.

What plants are good for controlling erosion in our area? When choosing plants to cover a bank for erosion control, assess the conditions of the area you want to plant. Is it in the sun or shade? Is it a naturally moist area or dry? Do you intend to water it or go with our natural cycle of wet in the winter and dry in the summer? Matching the plant to the site conditions will ensure success. California natives are well suited to this job.

If the area you need to stabilize is large and mostly shade, consider ribes viburnifolium or Evergreen Currant. Like mahonia repens or Creeping Mahonia it needs no irrigation when established. Another native, the Common or Creeping Snowberry can also hold the soil on steep banks, spreading by underground stems that stabilize the soil.

A bank in the sun would contain a different plant palette. Common native shrubs for sun include ceanothus groundcover types such as ‘Centennial’, ‘Anchor Bay’ and maritimus that are not attractive to deer like the larger leaved varieties. Manzanita are also excellent at controlling erosion.

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Western mock orange aka philadelphus lewisii

Some other good California native shrubs for erosion control are Western redbud, mountain mahogany, Western mock orange, lemonade berry, toyon, bush poppy, matilija poppy. spicebush, pink flowering currant and Western elderberry.

Smaller natives that put down deep roots are yarrow, coast aster, California fuchsia, wild grape, mimulus, buckwheat, wild rose, sage, deer and needle grass, Pacific Coast iris, penstemon, artemisia and salvia.

Remember when setting plants on a steep slope to arrange them in staggered

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California fuchsia

rows. Make an individual terrace for each plant and create a basin or low spot behind each one ( not around the stem ) to catch water. Set the crowns of the plants high so they won’t become saturated and rot after watering and make sure mulch does not build up around the stem.

These suggestions are just a few of the plants that control erosion. Every area is different and every situation unique.

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