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.
Design trends

Arbor Day in California

Plant a Strawberry tree like this one. My neighbor Grace loves to sit in it.

California’s Arbor Day is celebrated on March 9th this year. It’s actually a whole week n honor of famed horticulturist Luther Burbank’s birthday. The day is celebrated on different dates around the world because one of the features of Arbor Day is the planting of trees which is best done at certain times of the year in your area. The simple goal of this day is to inspire people to plant, nurture and celebrate trees.

We are fortunate to live in a temperate rain forest with lots of trees. Our redwoods are especially important in our biodiverse watershed as is all flora and fauna in the forest. Redwoods and many native trees keep our environment moist. Let’s make it a priority to protect them and pass the baton of stewardship to our children who will inherit this place.

So whether you’ve been thinking about planting a redwood, heritage oak or other native tree, a fruit tree to feed the family, a shade tree to save on summer cooling, a flowering tree to attract pollinators, or a tree to hang the hammock on this is a good time to plant as well as nurture and celebrate all trees..

Trees are remarkable in how they grow and adapt to their environment. Some trees, like redwood, ponderosa pine, sycamore and madrone have especially beautiful bark. This is the tree’s protection from the outside world. Continually renewed from within, it helps keep out moisture in rain and prevents the tree from losing moisture when the air is dry. Bark insulates against cold and heat and wards off insect enemies.

The inner bark, or phloem, is the pipeline through which food is passed to the rest of the tree, It lives for only a short time, then dies and turns to cork to become part of the protective outer bark.

The next layer in is the cambium cell layer which is the growing part of the trunk. It annually produces new bark and new wood in response to hormones that pass down through the phloem with food from the leaves. These hormones are called auxins and stimulate growth in the cells. They are produced by leaf buds at the ends of branches as they start growing in spring.

Inside the cambium layer is the sapwood or xylem which moves water from the roots to the leaves. Sapwood is new wood. As newer rings of sapwood are laid down, inner rings lose their vitality and turn to heartwood.

Finally, the central supporting pillar of the tree is called heartwood. Although dead, it will not decay or lose strength while the outer layers are intact. A composite of hollow, needlelike cellulose fibers bound together by a chemical glue called lignin, it is in many ways as strong as steel.

Leaves make food for the tree. Their shapes help them reduce wind resistance, shed rain that could decay the leaf if left standing and produce chlorophyll. The narrow needles of a Douglas fir, for instance, exposes as much as three acres of surface to the sun.

Be kind to all trees. They are a valuable asset to your home and our environment. Earth Day is next month on April 22nd. Let’s continue to celebrate the natural beauty of our planet and learn what we can do to keep it healthy.

Design trends

Early March in the Garden

Forsythia ‘Kolgold’

Almost overnight, although maybe I’m judging by rain storms, spring is upon us. The birds sure know it is and I’m seeing trees in bloom and new growth on the perennials. The tree frogs are croaking and looking for mates, the weeds are happily trying to grow and set seed before we notice them. But whether you want them to or not all gardens change with time. It’s part of nature that the fittest survive. Possibly you have different ideas of what you want your garden to look like but it’s hard to fool Mother Nature.

I don’t have my Blireiana flowering plum anymore but it was a tradition for me to pose next to it with my birthday presents in late February. It was one of my favorite early spring blooming trees with double pink blossoms and 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 doesn’t officially begin until March 20th but hey, we live in California.

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. 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. Forsythia 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 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

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.

Hardenbergia ‘Happy Wanderer’

A beautiful vine that blooms in late winter is hardenbergia ‘Happy 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 enjoy at this time of year is Fragrant Sarcococca. The tiny white flowers of this plant are easily overlooked but you can’t miss their scent. I used to have one near the front door that greeted me with that vanilla fragrance every time I walked 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 dry deep shade where other plants won’t grow give this plant a try. They are easy to grow, deer resistant and trouble free.

Enjoy yourself in the garden at this time of year when everything is waking up.

Design trends

Phenology in the Garden

Always on the look out for potential problems in my garden, I can use all the help I can get. Solutions are out there. One of my go-to websites that I use to diagnose those problems is UC Integrated Pest Management or http://ipm.ucanr.edu. You can look up just about anything that may ail you in your garden. As a test, I went to the Plant problem diagnostic tool for Home Garden Turf and Landscape. Talk about a rabbit hole. I was on their site for hours looking up stuff. Try it. Your garden will thank you.

The daffodils are blooming. Will spring be early this year? When will I no longer need to worry about the danger of frost? How much is climate change affecting our natural world? We can all remember years when there was little rain in January and February and it feels like the Bahamas around here. Then there’s this year. The rainy season is upon us. But what are the plants around here doing? Leafing out early? How about those invasive plants around your yard? Look to phenology indicators to give you some insight.

Phenology – not to be confused with phrenology which claims that bumps on the head predict mental traits – is the study of key seasonal changes in flowering times, emergence of insects and migration of birds from year to year. When do they occur each year? Phenology is a real science that has many applications. In farming and gardening, phenology is used chiefly for planting times and pest control. Predictions for fire season are based on factors pertaining to weather as well as plant growth. Certain plants give a cue, by blooming or leafing out, that it’s time for certain activities, such as sowing particular crops or insect emergence and pest control. Often the common denominator is the temperature.

Websites like USA National Phenology Network at http://www.usanpn.org/ offer lots of information on the subject. The US Global Change and Research Program released the first 14 indicators of climate change. Among these is the Start of Spring indicator on this website which reflects the accumulation of heat sufficient to initiate leafing and flowering in temperature sensitive plants. Your own observations via Nature’s Notebook will help contribute to this research.

Indicator plants are often used to look for a particular pest and manage it in its most vulnerable stages. They can also be used to time the planting of vegetables, apply fertilizer or prune. Here are some common garden plants and what they indicate:

When daffodils begin to bloom, sow peas.
When dandelions bloom, plant spinach, beets and carrots.
When lilac leaves are the size of a mouse’s ear, sow peas, lettuce and other cool-weather crops.
When lilacs are in full bloom, plant beans.
Once lilacs have faded, plants squash and cucumbers.
When apple trees shed their petals, sow corn.
When dogwoods are in full bloom, plant tomatoes, peppers and early corn.
When bearded iris are in bloom, plant peppers and eggplants.
When locust and spirea bloom, plant zinnia and marigolds.

When forsythia and crocus bloom, crabgrass is germinating. When this happens the soil temperature at a depth of 4 inches is 55 degrees. Treat with an organic pre-emergent.
When crocus bloom, prune roses and feed your lawn.
Mexican bean beetle larvae appear when foxglove flowers open.

Record your own observations. Another great site is National Sustainable Agriculture Information Service at http://attra.ncat.org. Sites like these can also help you design orchards for pollination and ripening sequence, design for bee forage plantings, design perennial flower beds and wildflower plantings as well as plantings to attract beneficial insects and enhance natural biological control. How cool is that?