Category Archives: trees

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 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.1600
Laurel 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.

The Best Dogwoods & How to Grow Them

Alluvial Terrace Nursery

There’s nothing like learning about trees from someone who has discovered for themselves what makes a winner and how to grow it. Recently I had the opportunity to tour a small wholesale nursery near Corralitos. Jon Craig has evolved from Silicon engineer to a propagator of plants and trees and he’s all the happier for it. He laughs when he says he has loved plants for a very long time starting with his first job mowing lawns. As a former engineer it’s all about the research and the plants he grows showcase his success.

His very favorite tree is the dogwood. Not just any dogwood but the ones that bloom with the largest flowers for the longest time. There are four main species of dogwood trees. From the Himalayas in China comes cornus capitata, Korea is home to cornus kousa. Cornus florida grows on the east coast and the west coast is home to cornus nuttallii or Western dogwood.

Jon Craig with cornus capitata ‘Mountain Moon’

We are all familiar with the Eastern dogwood that blooms early in the spring. It’s beautiful but rain and wind can cut short the flowering season many a year and the root system is prone to disease. Our Western dogwood is prone to leaf spot fungal diseases. 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 roots. Vesuvius series is a cross of our native nuttallii with a florida as is Eddie’s White Wonder. There is also a nuttullii-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

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. That tree is Jon Craig’s very favorite. With a name like Mountain Moon you can just picture it blooming high in the Himalayas. Huge flowers up to 6” 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. They are edible but bland and tasteless to us. The birds love then though and they remain on the tree while woodpeckers and robins have a feast.

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. 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 4pm. Add a couple of extra drip emitters or inline drip tubing to your irrigation system and they’re happy.

Ruby Fall redbud

Besides enjoying the hundreds of blooming dogwoods, I learned about a redbud that is not as fussy as the lovely Forest Pansy. Ruby Falls and Merlot promise to be more reliable in the garden and more heat resistant.

Jon will try his hand growing just about any plant that he thinks others will also enjoy. A fine crop of Alice oakleaf hydrangea grew near a block of Michelia ‘Inspiration’ getting ready to flower and scent the air. The lilacs had finished blooming but the peonies were just starting their show. Jon shared a tip about tree peonies he learned recently from a well-seasoned Japanese gardener. He followed her advice and cut back the tree peony stem in the dormant season forcing it to produce new stems. Voila- they are now loaded with flowers.


Jon grows many other types of dogwood and also Copper beech, magnolia macrophylla, Royal Raindrops crabapple , Sheri’s Cloud nyssa and even a Purple-leaved hazel. I could only fit a couple of 5 gallon cans in my car so a beautiful smoke bush in full bloom and a Black Lace elderberry now call Bonny Doon home. But I have my eye on one of those spectacular Mountain Moon evergreen dogwoods for the back garden.

The November Garden

Cercis_Forest_PansyOutside my window, the Forest Pansy Redbud has started to display its spectacular burnt 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. Out back I have a Catawba Crape Myrtle also starting to show fall color. Its leaves are turning a rich butterscotch shade which is lovely but not the reddish-orange described in the books. What causes fall color to vary from plant to plant? How does location in the garden, weather, climate and growing conditions affect what you see each fall?

The brilliant fall color we see in the leaves of trees and plants is always there. It’s just masked by Japanese_Maple-fall_color.1280chlorophyll during the growing season as the plant is busy making food while the sun shines during photosynthesis. Come autumn, shorter days and cooler temperatures cause the trees to switch into energy-storage mode, at which point 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 and yellow and orange carotenoids that make fall foliage so glorious.

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. A warm, wet autumn will almost surely result in less-than-spectacular foliage because the process of chlorophyll loss will be less consistent. Freezing temperatures or winds meanwhile can cause leaves to drop suddenly denying them opportunity to enter their slow, colorful dormancy. Finally, trees that are under stress because of pests, disease, injury or drought may drop their leaves with no color change at all.

Japanese_Maple-fall_color2.1280So if your garden becomes shady early in the fall this may result in less vivid fall foliage. If your trees are stressed by drought like this year you may not get the usual colorful fall display. These and the above factors all affect the intensity of fall foliage colors.

Now is a good time to shop for plants and trees that can punch up the color of fall in your garden. Seeing your new addition in person will show you exactly what color you are going to get. Sure Autumn Gold Ginkgo will probably always color up bright yellow and Sango Kaku Japanese maples will show off their characteristic golden foliage but the fall color of Purple Smoke Bush, Katsura tree, Witch Hazel, Pomegranate, Oakleaf Hydrangea and Blueberry, to name just a few, can vary.

First Frost
I received an email from someone new to the area about when to expect our first frost. I’ve kept a weather Japanese_Maple_Sango-Kaku_fall_color.1600journal since 1992 and based on my records occasionally we get a light frost at the end of October. Mostly though, the earliest frost has occurred about second week of November with late November being the most common. Be prepared by moving frost tender plants under overhangs if possible or having frost blankets (not plastic) ready to cover delicate plants.

Transplanting in Fall
Need to move a plant or install plants out of containers and into the garden soil? Now through February offers the best time to do this. Soils are still warm at this time of year which helps new roots get established quicker than in later winter.

Prepare the new location first before excavating any plant. Dig a hole twice as wide as the rootball, but just the same depth. Use a sharp spade to make clean cuts through roots. Cut roots will form new, dense and healthy roots.

Before replanting, especially from a container, check for roots that have circled the interior of the pot. These must be tugged loose and straightened when planted. Don’t be shy about loosening roots. When replanting be certain to keep the rootball at the same level it was and don’t add soil over the rootball. Most plants need oxygen at the soil level.

Trees of Stanford University

Flame_treeThe other day I visited the campus of Stanford University to view something from their archives. The campus is beautiful. Flowering trees in bloom every where you look. I was told by a colleague that Stanford has a huge collection of trees some planted back in the late 1880’s when the university was first built and the landscaping installed. The designer, Frederick Law Olmsted, the famed landscape architect also created New York’s Central Park. I wanted to find a mature specimen of a California native, the Catalina Ironwood, which is listed in their Encyclopedia of Stanford Trees, Shrubs and Vines.

The campus is huge and with so many areas to explore I missed the grove of Ironwood. There are over 400 species, 150 genera and 60 families which total 27,000+ individual trees growing on the central campus. Senator Leland Stanford vowed that no healthy oak be cut down and even today the dominant tree on campus is the coast live oak. There has been a loss of diversity from the original tree and shrub plantings of the 1880’s and 1890’s, which is well documented for conifers. Still the sheer number and variety of trees is impressive.

In the main quad by the Memorial Church and the grounds surrounding the Music library and the Green library I found dozens of trees which were all surveyed and named on a map I found online. It was fun to locate each tree.

I’m always on the lookout for mature tree specimens to photograph. When I recommend a tree to be included in a design I like to be able to share the image of what the tree will look like in the future. Trees anchor your house to the land. They are more than just a pretty face to look at from the kitchen window. They provide habitat, food and shelter to birds as well as giving shade in the summer. Some of the trees I saw on the Stanford campus may not be suitable for all gardens but they are interesting to learn about. Here are a few of the highlights of my campus botanical adventure.

In the main quad there are 8 circular planting beds containing over 80 individual trees. One that I was attracted to because of its unusual trunk and branching structure was the Flame tree or brachychiton acerifolius. Although not yet in bloom it will soon be covered with scarlet bells. I learned from the campus encyclopedia that this tree was planted in 1998 after the original specimen died. That flame tree, planted in 1891, was famous for the brilliant display it put on in May and June, covering the ground with a mantle of red bells. The pod-like fruits contain masses of irritating bristles but also nutritious yellow seeds that were eaten by the Aborigines after toasting.

The next tree that caught my eye had such formidable thorns that I wondered where it grew naturally. Floss-Silk_treeHow could it come by the pretty name, Floss Silk tree, with those deadly spines? I learned in September this tree redeems itself with masses of showy pinkish-white flowers so numerous they hide the foliage. Hummingbirds enjoy the nectar of the flowers which are used in Brazil as threads in upholstery. But the most distinctive feature of the tree is the wicked looking array of stout spines that crowd the trunk and protrude by an inch or more. Who knows why they evolved this way? The fruit of the Floss Silk tree is very large and on ripening the pods open to expose masses of white cottony kapok-like material that perhaps acts as a barrier to rats seeking the tiny seeds. Is it rats that the trees are hoping to deter by growing the huge spines?

Red_mulberryRedwoods, giant sequoia and Bristlecone pine live a long time but there’s something impressive about an ornamental tree that is over 100 years old. Planted in 1889, the trunk of the Red Mulberry tree growing in the quad has attained great character and girth. Mulberry leaves are the food of the silkworm and if you grow your own silkworms you can make silk. One silkworm produces about half a mile of incredibly strong monofilament to make its cocoon. The pale berries of the red mulberry are not as good to eat as the black mulberry but both grow quickly to provide shade for your home or patio.

A tree planted for beauty shade, habitat and posterity is a gift to all.

Beni Kawa Japanese Maple

Last fall my sister lost her favorite tree in a windstorm. She lives on Fox Island in the southern part of Puget Sound. I remember hearing about the extraordinary Pacific storm on the national news shattering records in the Northwest. Gusts up to 76 mph closed bridges, falling trees hurt 2 people and thousands lost power. Her Silk Tree didn’t stand a chance.

Won_Yang_JanWhile visiting over the Christmas holiday I thought it would be a nice present to replace her dearly departed tree. Several nice ornamental trees made the short list including the Katsura tree with leaves that smell like vanilla in the fall and Forest Pansy redbud with magenta spring flowers, burgundy heart-shaped summer leaves and reddish-orange fall color. We also considered the native Pacific dogwood but she already had one in the yard. Driving around we started to notice the beautiful color of the Coral Bark Japanese maples in many landscapes and the decision was made.

I knew we would have no trouble finding a good specimen in the Pacific Northwest and I was right. Close Won_Yang_graftsby in Gig Harbor we found Yang’s Nursery and I walked into the realm of a Japanese maple expert. Owner Won Yang opened the nursery to give us a tour of the grounds.  We walked between rows of hundreds of maples and marveled at the huge bonsai specimens of Weeping Katsura tree, Harry Lauder’s Walking Stick, several different conifers and a very impressive, beautifully pruned Oshio Beni Japanese maple all over 20 years old.

Won showed us his greenhouses where he propagates the maples himself. He has been in the business for 30 years so he knows his stuff. Starting with a small green maple seedling with a half inch stem that is cut off 6″ above the ground,  he carefully grafts a tiny tip of new growth from the desired specimen onto the larger stem. It will take at least 3 years before the new tree will be big enough to sell. Won’s pride in his work was apparent as he smiled at the rows of newly grafted maples.

Acer_palmatum_Beni_KawaBack out among the maples, I had my eye on the rows of coral barked Sangu Kaku maples when I saw them. Lined up alongside were several trees with bark so bright I couldn’t believe my eyes. “What are these”, I asked? Won just smiled and told me they were called Beni Kawa Japanese maples and were a cultivar originally developed in 1987. They are prized for their brilliant salmon red bark which is much brighter than the regular coral bark maple. I was hooked. How could I not plant this gorgeous tree in my sister’s yard?

I learned that the bark of this tree can be polished to keep the bright color. Lichen often grows on older trees hiding the salmon red bark of the new branches. I’ll have to try using a soft cloth on my coral bark maple and see how it turns out. The Beni Kawa is a fast growing Japanese maple that will eventually reach 10-15 ft tall and 5-12 ft wide. It is hardy to 15 degrees.

Won grows his trees in a 50/50 mixture of top soil blend and fine crushed bark. He fertilizes with a balanced granular fertilizer and prunes in the winter. The 6 ft tree I bought my sister will not need to be pruned for a couple of years allowing it to establish a strong root system.

I’m looking forward to seeing how the new tree evolves as it grows especially since I know where this Beni Kawa Japanese maple was born.

Why We Love Trees

When you look out your windows into your landscaping what catches your eye first? Maybe the hydrangeas are looking beautiful about now covered with giant flowers in sky blue, dark pink or white. Maybe it's the purple and red spikes of your salvias that both you and the hummingbirds enjoy. But I'll bet the most majestic and inspiring sight in your garden are the trees that frame your house giving it a sense of permanence, welcoming you home and providing a haven for songbirds that serenade you on a spring day.

cornus_capitata_closeupLarge or small trees make the world go round. They produce oxygen and act as a giant filter that cleans the air we breathe. A mature leafy tree produces as much oxygen in a season as 10 people inhale in a year.

Trees clean the soil by absorbing dangerous chemicals and other pollutants that have entered the soil. They can either store harmful pollutants or actually change the pollutant into a less harmful form. Trees can filter sewage and clean water that runs off into our streams. They can absorb and lock away carbon dioxide as wood so it is not available as greenhouse gasses.

If you live near a busy street trees can muffle the noise almost as effectively as a stone wall. They also act as a windbreak during windy and cold seasons reducing the drying effect of the wind and keeping it from blowing  precious topsoil away.

Trees slow storm water runoff helping to recharge our Santa Margarita and Lompico aquifers. On top of all the cool things trees do for us they provide shade and cool us in the summer. In the winter they break up the wind reducing heating costs. Trees increase property values.

If you've been thinking about adding a few trees to your own property here are some of my favorites. Some don't get enough recognition and some are classics. All make great additions to the garden.

Early in spring the flowering plums and cherries let us know that winter is over and a new season has begun. Then the dogwoods start to bloom and we're awestruck. Maybe you know of an especially beautiful specimen that gets your attention each year when it blooms. There are a couple varieties that I like to include in designs that are easy to grow and live for many decades.

Introduced to me by Barrie Coate, the renowned arborist and horticultural consultant, the Evergreen cornus_capitataDogwood, Cornus capitata, is also known as Himalayan flowering dogwood and lives up to its name in every respect. This under used tree is breathtaking in late spring and early summer with large flower bracts over 3" across.  A friend has one in her garden and it is the showiest tree on her property for several months. This variety is slow growing reaching 20 ft tall in sun or partial shade after about 25 years. After flowering, red fruit provides a treat for the birds.

Another dogwood variety that makes a wonderful addition to the garden is the Venus dogwood. I've heard it said that some consider it even showier than the Evergreen dogwood but I like them all. It's a fast growing deciduous hybrid with white flowers as large as your hand. Summer flowers give way to strawberry-like fall fruit as the leaves turn color. It's highly resistant to disease and drought conditions.  What's not to love? I also recommend Cornus Eddie's White Wonder for it's beauty and disease resistance.
If you would like a tree in a certain spot but don't have lots of room, consider  a Drimys winteri, commonly known as Winter's Bark. This evergreen, slender tree from Chile has aromatic mahogany-red bark which cured sailors in past centuries from scurvy and leathery fragrant leaves. Small clusters of jasmine-scented, creamy white flower appear in winter and spring. It grows to only 20 feet tall.

Other trees that are favorites of mine include Forest Pansy redbud for its stunning red foliage and Sango Kaku Japanese maple for its year round interest. Arbutus Marina, Oklahoma Texas redbud and Tristania laurina Elegant are also wonderful trees for the landscape.

Plant a tree for yourself and future generations.