Tag Archives: trees

Flowering Trees & Shrubs of Early Spring

Outside my window the Blireiana flowering plum is covered with dark pink, double blossoms. It’s one of my favorite early spring blooming trees with a sweet fragrance strong enough to scent the garden. We look forward to the earliest flowers of the new season knowing that winter will soon be over. Spring officially begins on March 20th.

Old fashioned shrubs like flowering quince and forsythia figure prominently in many old gardens because they are tough plants able to survive neglect and still look beautiful.

Forsythia ‘Kolgold’

The bare stems of forsythia are completely covered with deep golden-yellow flowers in late winter and early spring and become the focal point of the landscape when in full bloom. The showy stems of this easy care shrub are great for cutting. Forsythias are native to eastern Asia but a chance discovery in Germany by a grower who specialized in breeding for the cut flower industry led to the especially vivid variety ‘Kolgold’ in the 1800’s. Forsythia has long been used in Chinese medicine. The flower petals contain powerful bacteria-fighting properties which make it an important dressing.

Flowering quince

Flowering quince is another old garden staple providing early color. They are easy to care for and nearly indestructible in almost any soil that is well drained and not overly fertile. Once established quince is a very drought tolerant plant and their spiny branches make them an excellent choice for hedges, screening or as a security barrier. There are red, pink, orange and white flowering varieties. The Toyo Nishiki cultivar even has pink, white and solid red flowers all on the same branch.

Clivia miniata

What would a shade garden be without a bright orange clivia? Every year I look forward to their huge flower clusters that emerge from between dark green, strappy leaves. Even in dark shade they will bloom and brighten the winter garden although they would do fine in morning sun. If you have a north facing window you can grow them as houseplants. Clivia are hardy to several degrees below freezing but mine, under an overhang, have survived temps of 23 degrees without damage. Clivia breeders have produced gold and peach colored flowers also but I still like the standard orange ones.

A beautiful vine that blooms in winter is hardenbergia ‘Happy

Hardenbergia ‘Happy Wanderer’

Wanderer’. In the pea family, this evergreen vine looks like a small wisteria when in bloom. Pinkish-purple flowers cascade in clusters on twining stems that reach 12-16 feet long. It requires little water once established and is hardy to about 23 degrees. If you have an older, tangled plant you can rejuvenate it with hard pruning in early spring after flowering. Never prune in late summer or fall because you will cut off the wood that is going to bloom the following winter.

The last plant I couldn’t live without is Fragrant Sarcococca. The tiny white flowers of this plant are easily overlooked but you can’t miss their scent. I have one near the front door that greets me with that vanilla fragrance every time I walk in or out. The flowers are followed by a bright red fruit. Sweet Box forms a natural espalier against a wall and if you have a problem spot in deep dry shade where other plants won’t grow give this plant a try. They are easy to grow, deer resistant and trouble free.

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.

April: For Everything there is a Season

crabapple_Pink_ProfusionSeems like just about everything is in bloom. Sure there are many plants and trees who’s season is still a ways off but the flowers of early spring really get our attention. Longer days trigger both flora and fauna to reproduce. Being that it’s the beginning of April I thought I’d give you a heads up on what to do in the garden this month. That way you can budget your time and enjoy the beauty around you and still get your chores done.

Earth Day is coming up on Saturday, April 18th and National Arbor day is April 24th. What better way to celebrate in your own backyard than to planrhodie_early_pinkt a tree, shrub, flower or edible? I’m enjoying the succession of flowering trees in my own yard. First came the plums, then the flowering crabapple and now the Forest Pansy Redbud. My crape myrtle will bloom by summer but I think I’ll plant another tree that will bloom in May to celebrate, maybe a late-blooming Kousa dogwood.

Planting a tree is having confidence in the future. Like the saying goes, “The best time to plant a tree is twenty years ago. The second best time is now.” In case you were wondering, Arbor Week in California was celebrated mid-March. That’s because each state observes Arbor Day based on the best tree-planting time in their area. On the first Arbor Day, April 10,1872, an estimated one million trees were planted. Make yours the one million and one tree planted.

Other to-do’s for this month include:

Fertilize -Take advantage of the moist soil to fertilize your garden. Lawns and groundcovers are beginning their spring growth spurt and new leaves on trees, shrubs and perennials are starting to emerge. Your citrus may be looking yellow from lack of nitrogen which has leached out of the soil through the winter season and they may be lacking in iron. Feed them with organic citrus or fruit tree fertilizer. Perennials benefit from both a fresh layer of compost and a light application of balanced fertilizer. They respond to the phosphorus from bone meal especially in the spring for root growth, stem sturdiness and flower development. Make sure you keep fertilizer off the foliage and crown of the plants or wash it off with the hose. Wait to feed azaleas, camellias and rhododendrons until after they bloom and you see new leaves emerging.

Transplant – If you need to move any plants in the garden that have outgrown their space or are not growing with other plants of the same water usage now is a good time. Plants are full of growth hormones and recover quickly from transplant shock. As you plant new additions to the garden add organic matter to the soil. If your garden’s soil is sandy, organic matter enriches it and allows it to hold water more efficiently. If your soil tends toward clay, organic matter will loosen it up and improve drainage. In well-amended soil, plants grow deep roots, are hardier for cold, more resistant to disease and more drought tolerant. Organic matter such as compost, planting mix and well-rotted manure boosts nutrition and improves soil structure.

Spread fresh compost or bark mulch around all your plants to help plants get off to a strong start. Good soil is the secret to successful gardening. The first principle of organic gardening is to feed the soil and it will feed the plant. Remember that all gardening used to be organic. Layer 2-3″ of compost or bark chips on top of the soil and let it slowly decompose and filter down into the earth. Bark nuggets and shredded bark do not increase your soil’s fertility like compost or bark chips but they do conserve moisture and help keep weeds at bay.

Check for aphids – They are out in full force sucking plant juices from the tender new leaves of everything from roses to hellebore to Japanese maples. A strong spray from the hose may be enough to dislodge them. If they still persist, you can spray organic insecticidal soap, neem oil or horticultural oil to kill them. As with all pesticide sprays, do this early in the morning or later when they are not in the sun. Be sure to test first to make sure the spray doesn’t burn the new growth and always mix according to the directions.

Ants can also bring aphids up into trees and shrubs such as camellias, citrus and roses. Ants feed off honeydew secreted by aphids, scale and other plant-juice sucking insects. Ants also protect these pests from natural predators. To keep them off, wrap trunks with a 1-2″ wide strip of masking tape and coat with a sticky barrier like Tanglefoot. Keep the barriers free of dirt and check them periodically for breaks. Reapply when necessary.

The most important to-do for early spring is to take time out and enjoy your garden and our beautiful surroundings. Those last few weeds will be there tomorrow but you’ll never get another today.

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.

Tree Pruning Tips

limbed redwoods.1600The big wind we experienced not long ago was just the beginning of the wild weather that is coming our way. Looking up at the trees violently swaying from one side to the other I wondered how they could survive such strong wind gusts. Not all of them do survive coming down and blocking driveways, roads and sometimes landing on a house or a car. There are ways of trimming, pruning and managing trees that can help them stay upright in a strong wind. Don’t endanger yourself, your family, your property or your valuable trees by mismanaging this valuable resource.

You’ve seen it. A homeowner wants more sun and has their redwoods limbed way up so there is just a a tuft of branches and foliage at the top. Living in the forest myself I can understand the desire for more sun. Why is this bad for your trees? What is a better way to ensure the health of the tree and still have space to walk or park under them or open up a view?

Raising the height of the lowest branches or limbing up is often done to create clearance in an area where people will walk or park. Seven feet is your target height . Over pruning removes many of the energy producing needles and leaves taking away most of the trees ability to photosynthesize. Evergreens don’t have food reserves like deciduous trees. They may even die completely in 8-10 years or topple in a heavy wind because they have become so top heavy and have lost their windbreak effectiveness.

Removing the lower limbs of redwood, cedar, pine or other conifer is needed to remove dead and dying branches which improves circulation and makes them more fire resistant. It’s done naturally in the woods when limbs die and fall off. If you must remove live lower branches do it over a longer period of time to reduce stress on the tree. The amount trimmed off should not exceed 25% of the total foliage. 10-15% is better but not always attainable.

Windowing of a tree should follow the same guidelines. To open up a view and preserve the health and beauty of your trees, here are some ways to make views and trees work together. According to Plant Amnesty, windowing or cutting selected branches, works best when the subject is a large, close-in tree blocking your view. By carefully choosing what to cut you can open a window in that tree to give you a fully framed view of whatever lies beyond. Like most pruning, there’s a certain amount of art involved in this. Never top a mature tree it’s arboreal butchery.

If you’re trying to decide whether or not to limb up evergreen trees in your yard, do your homework first. Oregon State University Extension Services recommends pruning when the treclear cut hillside.1600e is not actively growing. This is late winter to very early spring, well before any new growth will take off in the new season. For our area January and February is best. Redwoods go into a short period of dormancy at that time making it the best time for pruning. This gives them a chance to heal the cuts you make with their first burst of new growth in the spring.

Another scenario that wreaks havoc with the land is to clear cut large sections of forest. When you do this the trees left behind on the fringes are not prepared to deal with high winds. They grew up being protected by the trees around them and their trunks are not as strong. Trees channel the wind over the top and buffer it before it hits the ground. By clearing the land completely the wind barrels through the open area and hits the next thing in its way which may be your house or deck or landscaping. It’s better to remove selected trees completely.

Put away the saw and enjoy the beauty of your mature evergreens. Prune lightly. Preserve your trees natural shape. A properly pruned tree will look as natural as possible.

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.
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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.