Category Archives: trees

dogwoods, Flowering trees, plant diseases, planting tips, trees

The Best Dogwoods & How to Grow Them

Alluvial_Terrace_wholesale_nursery
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.

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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.

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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.

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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.

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peony

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.

color in the garden, colorful foliage, fall foliage, gardening tips, last frost date, trees

The November Garden

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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.

Flowering trees, hummingbird plants, Stanford University trees, trees

Trees of Stanford University

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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.