Category Archives: Design trends

All About Soil

This pine tree growing in Bryce Canyon must have found just the right soil to survive.

“The soil is made of butterfly wings, dinosaur teeth, pumpkin seeds, lizard skins, and fallen leaves.                 

Put your hands in the soil and touch yesterday, and all that will be left of tomorrow shall return so that new life can celebrate this day.” 

-Betty Peck

Soil makes all the difference to the plants you grow. The biggest issue we gardeners face is the ongoing battle with soil. If yours is difficult to manage or unproductive you’ll be disappointed with the performance of many of the plants you put in the ground. Even tough plants like California natives have soil preferences and they are not always what’s in your garden.

We live on ancient sea cliffs. Soils in Bonny Doon and Scotts Valley consist of shallow, excessively drained weathered sandstone and shale. Felton soils were formed from shale, sandstone or mica schist. Those in Ben Lomond and Boulder Creek had their beginnings from weathered sandstone or granite. Although these provide the necessary mineral component of our soil, organic matter or humus from decayed plant and animal material are necessary for fertility.

Here’s why improving your soil will make a difference to the health of your plants.

Gardens in Poland use organic methods to increase soil fertility.

Good soil-with both organic matter and minerals-helps plants grow by forming the food supply for soil bacteria that help make food available for plant growth. Most of a plants energy goes to producing substances that drip out through the roots to attract bacteria and fungi. These in turn attract good nematodes and protozoa to the root zone. The protozoa eat bacteria and the nematodes eat not only the bacteria but also fungi and other nematodes to get carbon. What they don’t need they expel and this feeds the roots much like earthworm castings.

Down in the soil, if a plant needs different foods it can change what is secretes. Different substances will attract different bacteria, fungi, nematodes and protozoa. This huge diversity of soil biota helps the good guys keep the bad guys in check.

A common way to destroy the microbiology of the soil is to add salts in the form or non-organic fertilizers. The salts kill the bacteria and fungi by dehydrating them. Then the plant can’t feed itself and becomes dependent on its fertilizer fix. Without the good bacteria and fungi in the soil other parts of the food chain start dying off as well.

The soil food web is also responsible for soil structure. Bacteria create slime that glue soil particles together. Fungi weave threads to create larger soil particles. Worms and insects distribute bacteria and fungal spores throughout the soil and create pathways for air and water.

What can you do to bring your soil back to life?
• Mulch around perennials, shrubs and trees with1/4“ of compost and 2-3” wood chips or other organic mulch.
• Apply mycorrhizal fungi, especially in a new garden that’s been rototilled or chemically fertilized. You can find this in most organic fertilizers and some organic potting soils.
• Use aerated compost tea
• Try to avoid walking on the root zone of plants. This kills fungi in the soil. Install stepping stones to preserve soil structure.

Feed your soil- not your plants.

Attracting Bees, Butterflies and Birds with California Native Plants

This collection of California natives includes heuchera, Douglas iris and carex grasses.

It’s always a breathtaking experience taking a walk at this time of year. You might see the cobalt blue flowers of ceanothus or a stand of dicentra formosa with their dainty pink bell-shaped flowers backlit in the spring sunlight. Coral bells are in full bloom as are the Pacific coast iris. These are just a few of our local native plants. Everywhere you look nature is beginning the season fresh with anticipation and promise.

California is a vast domain when it comes to natural features and different soils. From hills to mountains to deserts to valleys and ocean bluffs, there are 6000 plus plant species within our borders. Hundreds of these are showy and useful plants worthy of cultivation in our garden. Some, like ceanothus, have already been cultivated for a century or more, both here and abroad.

There are features of the California landscape that present a certain flavor and seasonal progression, quite distinct from that of the subtropics and year-round, moist forests that many traditional garden plants come from. Plants of hilly and mountainous areas are often found in rocky or sandy soils and require well-drained garden soils. Many plants of the chaparral have poor resistance to the root pathogens that thrive in a warm, moist soil and may not tolerate typical garden style irrigation in summer.

Matching or creating the right conditions is the key to success to grow California natives. Planting on a raised mound or berm, for instance, is one way to drain water away from sensitive crowns. Knowing where in California a given native plant comes from can help you make the right decisions.

That being said there are many natives with an amazing broad tolerance of different conditions. Toyon (Heteromeles arbutifolia) grows in both sandy and clay soils as does yarrow (Achillea millifolium) which is also a good cut flower. Carex grass and Seaside daisy (Erigeron glaucus) also do well in most soils.

If you garden in clay soils, good native shrubs are Western redbud, manzanita, spicebush, bush anemone, ceanothus, garrya, Pacific wax myrtle, Western mock orange, blue elderberry, mahonia, California wild rose and snowberry. Native perennials for clay soil include coral bells, sticky monkeyflower (a good cut flower), salvias, deer grass, rubus and Dutchman’s pipe vine.

This collection of Pacific Coast iris is growing in Gamble Gardens in Palo Alto. Pacific Coast iris include 11 species and 8 subspecies of iris including the Douglas iris.

Sandy conditions require California natives that are decidedly drought tolerant. You may already grow many of our manzanitas and ceanothus. But do you also have lupine, lavatera, coffeeberry, buckwheat, fuchsia-flowering gooseberry, purple sage, wallflower or the beautiful Douglas iris?

Then there are the folks that live in the shade. Native plants from canyons and riparian areas will do well in your garden. They require some summer watering but that’s all. Native shrubs that tolerate bright shade are manzanita, spicebush, bush anemone, ceanothus, mahonia, Pacific wax myrtle, any of the ribes, wild rose, snowberry and huckleberry. Perennials for color are columbine, Western bleeding heart, California. fuchsia, Douglas iris and coral bells.

Where ever you garden, to provide food, nectar or berries for our winged friends be sure you have some flowering currant, sticky monkey flower, coffeeberry, salvia clevelandii, Dutchman’s pipe vine, wax myrtle, California fuchsia, aster chilensis.

Dogwood Magic

Hopefully this Eastern flowering dogwood, shown here a couple years ago before the fire, will rebound.to it’s former glory.

It seems to happen overnight. The dogwoods are blooming and they’re spectacular. You can’t miss hose huge bright white or pink bracts. I was pleased to see that the pink flowering dogwood on my old street in Bonny Doon has managed to bloom a bit despite surviving the fire and the lack of rainfall last year. Life can be tough. Nature is tougher.

Dogwood are a good tree choice for the allergy sufferer as their pollen is not wind borne. Their showy flowers, which are actually bracts, are pollinated by insects. Their pollen is large and heavy, sticking to insects rather than becoming airborne and leading to sneezing, runny noses and watery eyes.

There are four main species of dogwood trees. From the Himalayas in China comes cornus capitata. Korea is home to cornus kousa. Cornus florida is native to the east coast and the west coast is home to cornus nuttallii or the Western dogwood. I’m looking forward to enjoying our native dogwood bloom next month in Calaveras Big Trees State Park.

Our native Western dogwood is unfortunately prone to leaf spot fungal diseases when grown out of their range. They are a little temperamental in the garden before they reach the age of 10 years but after that they tolerate seasonal flooding and flower and grow with little care in morning sun or light shade.

Cherokee Chief dogwood

We are all familiar with the Eastern dogwood (cornus florida) that’s blooming now. With various shades of pink, red or white blossoms they are stunning. Take note that their root system is prone to disease if not grown with good drainage.

The Kousa dogwood is a more drought tolerant, disease resistant and a tougher plant all around. Large, showy flowers open after the tree has leafed out and remain for a long time. This makes it good for hybridizing with other varieties.

The Stella series is a mix of a florida on kousa dogwood rootstock. Vesuvius series is a cross of our native nuttallii with a florida as is Eddie’s White Wonder. There is also a nuttallii-kousa cross called Venus that displays huge flowers and gets its disease resistance from the kousa roots. All these cultivars strive to produce a tree with superior disease resistance and huge, long lasting blooms.

Mountain Moon- A long blooming disease-resistant variety

Deciduous dogwoods don’t like wet feet especially in the winter. That’s how they develop fungal disease. But there’s an evergreen dogwood that can handle moisture all year round. Cornus capitata Mountain Moon is a tough tree that can handle strong winds and isn’t bothered by any pests or diseases. They enjoy lots of organic matter as do all dogwoods. Huge flowers up to 6 inch wide can last from late spring into early summer. After flowering, the fruits begin to form and grow into red balls about the size of large strawberries. This is the reason is it also known as the Himalayan Strawberry Tree.

Dogwoods attract a variety of wildlife. All sorts of critters use this tree for food and shelter. The giant silk moth and several species of butterflies favor dogwoods as host plants. The spring flowers provide nectar to bees and other pollinating insects. Robin and sparrow are just two of the bird species that build nests on the horizontal branches and many others seek shelter in the leaves. The high calcium, high fat, fleshy red fruits are eaten by 35 species of birds including titmice, juncos and waxwings.

Many people think of dogwoods as an understory tree but this location is often too shady. Grow them in a full or partial sun location that gets afternoon shade after 4:00 PM. Add a couple of extra drip emitters or inline drip tubing to your irrigation system and they’ll be happy.