All posts by Jan Nelson

I am a landscape designer and consultant in the Santa Cruz mountains in California. I write a weekly gardening column for the Press Banner newspaper. I am also a Calif. Advanced Certified Nursery Professional and managed The Plantworks Nursery in Ben Lomond, Ca. for 20 years.

Controlling Erosion

All ceanothus are deep rooted and provide excellent erosion control.

That 2 1/4” of the wet stuff that a couple weeks ago was most appreciated. Turned out to be more rain than I anticipated arriving slowly so as to sink in and really do some good. The ducks in Boulder Creek are happy again.

Who knows what our La Niña weather will be like this winter but we do know that some of our rain events will come with a vengeance. It’s not that unusual for our area to get 8 inches of rainfall during a storm and that can create havoc on an unprotected hillside. Fortunately, October is a good time to do something about it.

Fall is the perfect time to plant in our area. The soil is still warm encouraging root growth and the weather is mild. Using the right plants on hillsides can help slow and spread runoff and prevent soil erosion. Mulch also protects soil from direct rain impact and slows runoff across bare soils. Covering the steepest slopes with jute netting through which plants may be installed is an added precaution.

There are many attractive plants that work well for erosion control. Often they need to adapt to shallow, poor soil and cope with less than ideal conditions all while putting down dense, strong roots. California natives are well suited to this job.


Common native shrubs include ceanothus and manzanita of all types. Calycanthus or Spicebush has fragrant flowers in late spring blooming well into summer with a spicy fragrance. The foliage is aromatic when crushed and changes from a spring green color to pale golden in autumn. Decorative woody fruits last into winter making this shrub attractive year round. It thrives with infrequent to moderate watering. Combine with coffeeberry and deer grass in sunnier spots or with Douglas iris and giant chain fern in shaded spots below trees. All these plants have deep roots and control erosion.

Ribes sanguinem or Flowering Currant is another show stopper capable of controlling erosion. In the spring the long, flower clusters of this deciduous shrub will dominate your garden. Choose from white flowering ‘White Icicle’ or ”Barrie Coate” and ‘King Edward VII’ with spectacular deep red flower clusters. ‘Spring Showers’ has 8 inch long pink clusters. Grow in full sun to partial shade. This California native requires little water once established and is a valuable nectar source for hummingbirds.

Some other good California native shrubs for erosion control are western redbud, mountain mahogany, western mock orange, lemonade berry, toyon, matilija poppy and western elderberry. ribes viburnifolium, creeping mahonia and baccharis. Ceanothus maritimus, ‘Heart’s Desire’ and ‘Anchor Bay’ are all good ground cover selections and are not attractive to deer.

Symphoricarpos – Common Snowberry or Creeping Snowberry – can hold the soil on steep banks. This native tolerates poor soil, lower light and general neglect.

Smaller natives that put down deep roots are yarrow, coast aster, California fuchsia, wild grape, mimulus, buckwheat, wild rose, sage and salvia.

Bush Poppy

Bush poppy (dendromecon rigid) is another native found right here in our area and needs no irrigation at all once established. Beautiful bright yellow, poppy-like flowers cover the plant in spring. They can be propagated from cuttings taken in summer and are pest and disease free.

Low water-use non-native ground covers like cistus salviifolius, grevillea lanigera, rosemary prostratus, rubus pentalabous, correa and sarcococcas are also good low-water choices.

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

Planting California Natives in the Fall

In the California native plant garden at Gamble Garden this coral bells provides a beautiful focal point and the hummingbirds love it also.

When my optometrist was in Palo Alto I used to stop by Gamble Gardens on Waverly Street to see what was in bloom. Just down from Steve Jobs house, this historic garden dating back to 1908 is aa treasure. Over 300 volunteers keep the garden looking beautiful and it’s open to the public for free every day. The California native plant garden is one of my favorite areas. Fall is the perfect time to plant in your garden. Here are some ideas.

By planting from mid-September through mid-November, roots of all plants have a chance to grow during fall and most of the winter without having to supply nourishment to the leafy portion of the plant. Roots of deciduous plants still grow even after plants drop their foliage as long as the ground temperature is above 50 degrees. Cooler day and night temperatures slowly harden off the top of the plant to prepare for the cold days of winter.

Another reason that fall is the “no-fail” planting season is because plants put in the ground in fall need less water to establish. The plants themselves use less water since photosynthesis is slowed by shorter days even if it’s occasionally warm. Evaporation rates slow down also during fall so moisture in the soil lasts longer as well. Sometimes we get lucky with fall and winter rains perfectly spaced so the ground never completely dries out. Unfortunately this winter is predicted to be another La Nina but let’s hope we get more rain than last season.

Plants that thrive in dry, shady spots benefit especially from fall planting as they need established root systems before next years dry season. Dry shade sometimes occurs in places beyond the reach of the hose but also under native oaks. To protect the health of native oaks, it’s a requirement that plants underneath thrive with little or no summer irrigation.

King Edward VII Pink Flowering Currant

Plants of proven success under these conditions include native currants and gooseberry. Red flowering currant is a show stopper capable of controlling erosion. In the spring, the long, flower clusters of this deciduous shrub will dominate your garden. There are many selections to choose from so if the huge white flowers appeal to you ‘White Icicle’ will be beautiful in your landscape. ‘Barrie Coate’ and ‘King Edward VII’ have spectacular deep red flower clusters and ‘’Spring Showers’’ has 8″ long pink ones. Grow in full sun to partial shade. This California native requires little water once established and is a valuable nectar source for hummingbirds.

Some other good California native shrubs for erosion control are western redbud, mountain mahogany, western mock orange, lemonade berry, toyon, snowberry, matilija poppy and western elderberry. Rbes viburnifolium, creeping mahonia, snowberry, ceanothus maritimus and ‘Anchor Bay’s are good groundcover selections.

Pacific Coast Iris ( iris douglasiana )

Smaller natives that put down deep roots are heuchera, iris dougasiana, native grasses, yarrow, coast aster, California fuchsia, wild grape, mimulus, buckwheat, wild rose, sage and salvia.

Bush Poppy

Bush poppy (dendromecon rigid) is another native found right here in our area and needs no irrigation at all once established. Beautiful bright yellow, poppy-like flowers cover the plant in spring. They can be propagated from cuttings taken in summer and are pest and disease free.

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

The Power of Nature

Although not a mangrove or salt marsh, this Ginkgo, one of the oldest living tree species in the world, does its best to absorb CO2 from the environment.

We live close to some outstanding research facilities. NASA Ames Research Center in Mountain View had a role in the development of the Webb telescope that launched earlier this year. Stanford University is on the cutting edge of many medical advancements. Lawrence Berkeley and Lawrence Livermore National Laboratories are front and center of many studies that affect our daily lives.

When I was a kid my father used to work at the Lawrence Berkeley Lab. As a welder during the 1950’s I remember him telling me about working on the Bevatron which was the state of the art particle accelerator being built there. The goal of Berkeley Lab has always been to bring science solutions to the world.

Their newsletter, now published online, reported the results several years ago of a study about the increased rate that the earth’s vegetation is absorbing human-induced CO2. Never underestimate the power of nature – especially that of plants.

A new study published in this month’s Berkeley Lab newsletter, has found that plants, especially sea grasses, mangroves and salt marshes, 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. They are even better than forests and can continue to do so for millions of years. The carbon found in coastal soil is often thousands of years old.

“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.

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. They continue to 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.

Several years ago during the Ebola outbreak, Berkeley Lab was one of the research facilities searching for a 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.

The current Department of Energy Lawrence Berkeley Lab newsletter reported that the site of the former Bevatron, that operated from 1954 to 1993, has been designated a historic site by the American Physical Society for its exemplary contributions to physics. Dad would be proud to have been a part at its inception.

The current issue of the newsletter features a study conducted along with Michigan State University and the University of Southern Bohemia (yes, that’s a real place) about microbial photosynthesis. According to the article this info could help researchers remediate harmful algal blooms and develop artificial photosynthesis systems for renewable energy among other awesome applications. Check out the Berkeley lab newsletter online if you’re into browsing the internet like me.

What to do in the Garden in September

Divide overcrowded perennials like bleeding heart over the next few months.

And just like that…summer is nearly over. We’ll get to enjoy our Indian summer for the next couple of months so I really I can’t complain. And I did fertilize my blooming plants this morning so I’m feeling pretty good about myself. Now if I only had more space to garden. Can I borrow some of yours? Here are some of the other garden chores to put on your to-do list for September.

It’s still a little hot to plant cool season veggies starts in the ground. They appreciate conditions later in September when the soil is still warm but temps have cooled. It is OK to plant seeds of beets, carrots, spinach, arugula, mustard, leeks, onions, peas, radishes and turnips.

Fertilize shrubs lightly one last time if you haven’t already done so last month. All shrubs, especially broad-leaved evergreens such as rhododendron, pieris, camellia, hebe, need to calm down, stop growing and harden off to get ready for the winter cold. Some plants have already set next year’s buds.

Roses especially appreciate a bit of fertilizer now, encouraging them to bloom another round in October. To keep them blooming make a habit of pinching and pruning off old flowers. Always cut back to an outward facing branchlet with five leaves. There are hormones there that will cause a new rose to grow much sooner than if you cut to one with only three leaves. You can always cut lower on the stem if you need to control height.

Deadhead flowering annuals and perennials as often as you possibly can. Annuals like zinnias, calibrachoa and cosmos will stop blooming if you allow them to go to seed. The same is true of repeat blooming perennials like dahlia, scabiosa, echinacea and lantana. Santa Barbara daisies will bloom late into winter if cut back now. I know a gardener who cuts back her Santa Barbara daisies 3 times per year and they seem to always be in bloom and look fresh.

These plants know they’re on this earth to reproduce. If they get a chance to set seed the show’s over, they’ve raised their family. Try to remove fading flowers regularly and you’ll be amply rewarded. If you want to start perennial flowers from seeds this is the time so that they’ll be mature enough to bloom next year.

Now through October, divide summer blooming perennials like agapanthus, coreopsis, daylily and penstemon that are overgrown and not flowering well. You can also divide spring blooming perennials like candytuft, columbine, astilbe, bergenia and bleeding heart but sometimes they don’t bloom the first spring afterwards due to the energy they use re-establishing themselves.

Another thing to do while out in the garden this month is to cut back berries vines that have produced fruit. Canes of the current season should be trained in their place.

It’s never too soon to start planning for erosion control in those areas that caused you problems during last December’s storms. You remember that lovely rain we had in October and then in December before the spigot was turned off early for the season? I used to recommend planting mid-september on but our climate is much hotter than it used to be so think October and November as the prime months to plant for erosion control.

The Sound of Music in the Garden

Japanese Forest Grass provides a soft rustling sound in the garden. It’s pet friendly and both cats and dogs enjoy nibbling on the foliage.

If you’re like me you hear different things when you are outside. I hear the buzz of hummingbird wings and their little chirp up in the trees waiting to defend their feeder. They bring a smile to my face. Sometimes it’s the silence that gets my attention. Where are the chickadees or pygmy nuthatches or the raucous scolding of the jays? Where is the wind, the rustling of the forest grass leaves? Other times the quaking of the redwood boughs a hundred feet up makes the garden come alive like giant wind chimes. Sound adds dimension to the garden.

I consider the music of the garden as well as plants and people when developing a design. I’m talking about how water, wind and wildlife play a big role in the music of a garden. Even the crunching sound as you walk on a gravel path brings your garden to life.

The sound of moving water in the garden not only attracts birds but soothes the soul. It can drown out unwanted neighborhood noise or sound as subtle as a violin. I enjoyed a table top fountain with a bamboo deer scare for many years until the raccoons discovered it. The sound was incredibly soothing on a hot day. Pondless waterfalls are easier to maintain if you aren’t interested in fish or water plants. Small recirculating garden fountains can be placed on your deck or patio or tucked into garden beds. Urn and jar fountains offer a hint of bubbling water and the soothing sound of flowing water to your landscape.

I use to have a different wind chime at each corner of my house. You can tell the direction of the wind, the intensity, even potential changes in the weather just by listening to the chimes. There are bamboo chimes available that produce a peaceful relaxing sound or musically tuned metal tubes or those made of wood or shells. Enhance the wind with these lulling sounds.

The wind is different in each season. Summer breezes cool you and also catch on a billowy plant to bring not just sound but movement. Ornamental grasses are the stars of the garden when the wind rustles through the leaves and seed heads. My Japanese Forest Grass is one of my favorites. Loose shrubs like butterfly bush, hydrangea, spirea, spice bush and bush anemone also sway in the wind and bring sound to the garden. Allow a larger plant like Japanese maple to spill into the path where you will brush against it slightly to create that sound you hear in the forest when you walk. Enjoy the rattle of seeds in pods like those of iris as they dry during the summer.

The sounds of wildlife are my favorites in the garden. Any type of pond or waterfall with some plants growing in or adjacent will attract tree frogs. Buzzing insects collect nectar and pollinate flowers. My simple birdbath is a magnet for robins, spotted towhees, chickadees, warblers, kinglets, purple finches and jays. The rest of their time they are performing expert insect control elsewhere in my garden .Hummingbirds are frequent visitors as they fight for territory and feed on spiders and nectar rich flowers.

Allow your garden to make music.

Hardy Geraniums in the Garden

Hardy geraniums are easy to care for and make lovely ground covers.

Last fall my neighbor planted the slope in front of their house with hardy geraniums- lots of them. Over the winter they were looking a bit scraggly and I was worried that maybe they had chosen the wrong ground cover for their situation. But no, come last spring their rich blue geranium ‘Rozanne’ burst into bloom and it’s a site to behold.

Most people use the common name geranium to describe what is actually a pelargonium. Ivy geraniums, Martha Washington pelargoniums and zonal geraniums are all pelargoniums. Hardy geraniums, also called cranesbill, look very different. Leaves are roundish or kidney-shaped and usually lobed or deeply cut. Flower colors include beautiful blue, purple, magenta, pink or white and often completely cover the plant with color. I’ll bet if you visited a garden on a tour or admired a picture in a garden magazine it contained true geraniums. Here are just a few strong performers available among the dozens of species.

Geranium maderense grows best in shade. This dramatic native of Madeira is the largest geranium with huge 1-2 foot long leaves shaped like giant snowflakes. Clusters of thousands of rose tinted flowers form on a 3 foot trunk. This perennial is short-lived but self sows freely. Add some of these architectural plants to your border for color and structure.

Blue flowers in the garden are always a hit as they combine so well with other colors. Geranium Orion‘s abundant clear blue flower clusters bloom over a long season. Use this 2 foot spreading plant in sun or part shade in a mixed border or as a groundcover. There are other blue flowering geraniums. I grow geranium ‘Brookside’ on my own garden. It’s on the second round of blooms. It’s large bright blue flowers are larger than ‘Johnson’s Blue’. ‘Rozanne’ is another common favorite with stunning blue flowers.

Looking for a fast growing variety? Geranium incanum which covers itself spring through fall with rosy violet flowers, fits the bill. Cut back every 2-3 years to keep neat. This variety endures heat and drought better than other types but needs some summer water. It self seed profusely which might be exactly what you want for a groundcover in a problem area.

Geranium Biokova

If pale pink is your color, plant geranium x cantabrigiense ’Biokova’. This excellent groundcover spreads slowly. The numerous one inch flowers are long lasting and cover the plant from late spring to early summer. Their soft pink color is indispensable when tying together stronger colors in the border and the lacy foliage is slightly scented.

Another geranium in the same family is ‘Karmina’. I’ve been growing this dark pink flowering variety for several years. With lush green leaves on a low spreading plant it’s pretty even when not in bloom.

There are a couple other varieties that are popular and deserve a try. They are Award Winning ‘Mavis Simpson’ and ‘Russell Pritchard’. Both have bright pink or purple flowers and make good additions to your perennials.

Give the hardy geranium a place in your garden.