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.

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.


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.

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 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 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 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?

Allergy Season is Here

My neighbor Sue answered her door sneezing and coughing with puffy eyes and a red runny nose that Rudolph would envy. We live among redwoods and it’s their mating season. predicts pollen levels will increase as alder, juniper and birch release their pollen. Then come the oaks and sycamores. Here are some tips if you love your garden and this beautiful place we call home.

Everybody blames the Acacia tree for their allergies but they are not the real culprits for the allergy sufferer. Redwood pollen is dispersed by the wind. Strong winds blow the yellow redwood “flowers”, which are actually the flowers of the male cone, to release their pollen. Unfortunately because redwoods live in such a narrow band of coast line, there is no allergy shot for those highly affected by them. But back to what you can do in your yard if you suffer from allergies.

Yes, the acacia trees are in full bloom. Being one of the first flowering trees we see they get our attention. Blooming acacias are often blamed as the cause of allergic reactions at this time of year but acacias are largely pollinated by insects and their heavy pollen doesn’t tend to become airborne. It’s the non-showy, quiet plants you have to watch out for. If you’re an allergy sufferer some plants are worse than others for you.

According to historical records for our area the pollen count is mostly moderate in February but don’t tell my friend Sue that. Depending on the weather, and show medium high counts only for a few days this month. If you’re an allergy sufferer you don’t need a website to tell you what the count is. Our native red alder is in bloom now and it, along juniper and birch, are the main culprits at this time. Grasses, ragweed and other weeds and most trees bloom and shed pollen in March, April and May. Then comes summer, then fall and with it other problems for the allergy sufferer. To further complicate and make matters worse for the allergy sufferer, climate change is making pollen season longer and more intense. You can’t control what’s growing outside your own yard but here are some tips for what to plant and not plant in your garden.

About 25-30 popular landscape plants are responsible for the majority of plant-related allergies in California. During the height of the pollen season- from late February to June- there are often thousands of pollen grains in every cubic meter of air. One can breathe hundreds of them with every breath. Though pollen can travel many miles, the majority tend to stay in the general area of their origin.

Although California native ceanothus are great plants for the birds and bees, their wind pollinated flowers aren’t so good for the allergy sufferer.

Redwoods, oaks, alders, ashes and other wind pollinated trees like olives, birch, box elder, cypress, elm, juniper, maple, fruitless mulberry, pine, walnut, willow and privet are the major source of spring pollen. Most native plants are good in the sneezeless landscape but if you have bad allergies or asthma it best to avoid wind-pollinated ceanothus, elderberry and coffeeberry.

You may not be able to avoid those culprits growing on other properties but you can get the most out of your own backyard by creating a sneezeless landscape. Replacing existing plants may be impractical but planning future plantings with these things in mind will save you a lot of headaches down the road and let you enjoy the sunshine outside in your garden.

Flower type is a good way to judge plants. The best looking flowers usually cause allergy sufferers the fewest problems. Plants with bright, showy flowers are usually pollinated by insects, rather than by the wind. These flowers produce less pollen and their pollen is larger and heavier, sticking to the insect rather than becoming airborne and lead to sneezing, a runny nose and watery eyes.

Some trees that are good for anti-allergy gardens are apple, cherry, dogwood, magnolia, pear and plum. Shrubs like azaleas, boxwood, lilac, rose-of-Sharon, hydrangea and viburnum are also not likely to cause problems. Good flower choices include alyssum, begonia, clematis, columbine, bulbs like crocus, daffodil, hyacinth. Also good are dahlia, daisy, geranium, hosta, impatiens, iris, lily, pansy, petunia, phlox, roses, salvia, snapdragon, sunflower, verbena and zinnia. Lawns of perennial rye grass, blue grass and tall fescue blends are usually OK as they will not flower unless allowed to grow to 12 inches or higher. Bermuda grass, on the other hand, can pollinate when the lawn is very short, sometimes as quickly as a few days after mowing.

We don’t know what’s going to happen rain-wise for us this spring. Symptoms can become worse for the allergy sufferer if the body reacts to the disappearance of the pollen following its initial appearance only to have to have more of it later in the spring. According to Dr. Stanley Fineman, an allergist with the Atlanta Allergy and Asthma Clinic, “You become sensitized to it, so when you’re…re-exposed, you can get an even more violent allergic reaction.”

Here’s to a sneeze-less spring for you allergy sufferers.

A Rose by Any Other Name

Compassion’ – my favorite rose

When Juliet tells Romeo that “a rose by any other name would smell as sweet” she must have been referring to the Compassion rose. Actually, this line is not in the original version of Shakespeare’s play but was an edit in 1599 according to Wikipedia but if you’ve ever smelled the Compassion climbing rose you’d not quibble over semantics.

Roses are the flower of love. Many of us have wonderful memories of favorites from past gardens or lovely bouquets that we were given or received on Valentine’s Day. It’s dormant season for roses which is a good time for adding a new one to your garden. And if you haven’t already pruned those in your own garden it’s not too late.

Roses, whether bush types, climbers or carpet varieties use a moderate amount of water similar to echinacea, hellebores and heuchera. Some roses like Cecile Brunner and rugosa need even less irrigation similar to cistus.

New this year from Week’s Roses is a shrub rose that can be trained at a climber. Cosmic Clouds has rich purple flowers with a white reverse and has a strong, fruity fragrance. This rose has a high disease resistance to powdery mildew, downy mildew and rust.

Another new rose from Week’s this season is Quest for Zest. A medium tall grandiflora, this double yellow rose with lighter yellow outer petals has both a strong citrus scent and is highly disease resistant. If only I had more sun I’d want this one, too, in my little garden.

It’s not too late to prune your roses if you haven’t already. Here are a few tips.

Most of us want our rose bushes to produce lots of roses on a compact shrub and not just a few exhibition size blooms so prune your shrubs moderately. The goal is to keep the center of the plant open for good air circulation aiming for a vase-shaped bush with an open center. Cut out canes that cross, appear weak or are diseased, spindly or dead. Healthy canes appear green or reddish while old and dying canes are brown. Cut back the remaining stems by about one third. When pruning, cut canes at a 45-degree angle just above an outward facing leaf bud or a swelling on the cane Slant the cut away from the bud to encourage growth outward. Clean pruners after every use to prevent the spread of disease and keep your pruners sharp.

Heirlooms roses such as David Austin, other old antique garden roses, and floribunda roses require less pruning because their open look is part of their charm. Keep this in mind and prune lightly. Old garden roses that bloom once in the spring should be pruned after flowering.

‘Compassion’ trained as a climber

Same goes for climbing roses. Cut out extra stems if there are too many and also cut back long established canes to about the place where they are slightly thicker than a pencil. Then cut each side stem down to several inches. This will make the cane flower along its complete length for a beautiful spring display.

It’s best to prune your roses before they start leafing out or some of their energy will be wasted. Pull off and rake away any old leaves. They can spread fungal spores. Consider spraying dormant plants with a combination of organic horticultural oil and copper soap or lime-sulfur. If you usually only have problems with black spot you can use a mixture of 1 teaspoon baking soda with a few drops of light horticultural oil in 1 quart water and spray every 7 to 10 days during the spring.

Prune your roses throughout the growing season, too. Deadheading, or cutting off spent flowers, encourages plants to re-bloom. Mulch around your roses to conserve water and encourage soil microorganisms.

Don’t worry whether your pruning job is perfect. Roses are super forgiving and you can always trim them up again later.

Bare Root Edibles – Invest in the Future

An apple tree planted now will live in your garden for 60 years

It’s not too late but time is running out if you’re looking to add fruit and nut trees, berries and vegetables to your garden while they’re still available in bare root. Did you know just how long that new fruit tree will be around if you plant it now? If you like figs or walnuts, you can expect your tree to live for 100 years. Apples and pears have a life expectancy of 60 years while plums, pluots and prune trees will be around for 40 years. Love cherries? Your new tree will be in your garden for 30 years. Invest in the future and plant a fruit tree now while they are still in bare root and oh, so easy to plant.

Jeff at Mountain Feed & Farm Supply in Ben Lomond recently showed me around all the edibles available at the store. I’m always on the look out for something new that I might recommend to a client for their garden and I found some good ones in addition to the classic fruit, nuts, berries and vegetables.

If you grow in containers or small spaces try the dwarf thornless Blackberry ‘Baby Cakes’. You’ll get two crops of large, classic, sweet tasting berries per season. Or you might have your eye on a multi graft peach, pear or cherry or a “fruit salad” multi grafted tree. Maybe a weeping Santa Rosa plum would look stunning outside the kitchen window? So many choices.

Jet, my go-to expert at Scarborough Gardens in Scotts Valley, had many great fruit trees still available in bare root. Because they are so beautiful in bloom, I’ve always wanted a dwarf peach or nectarine. From world famous Floyd Zaiger, Arctic Babe, a genetic dwarf white nectarine is a first of its kind. It’s a reliable self fruitful, delicious nectarine ripening late May to early June. Of course, there are apricots, pears, plums, apples, peaches and nectarines also available.

Planting a bare root tree is easy. In most soils, even sand or clay, bare root trees are best planted in your native soil. Less is more when it comes to amending your soil. You want our tree’s roots to reach far into the surrounding soil, and if you have added too much amendment, the roots will tend to grow only in the richest soil right around the tree. You can add a starter fertilizer like Dr. Earth Root Zone or E.B.Stone Sure Start with mycohizzal organisms and micronutrients.

Don’t plant in heavy saturated soil. If your soil drains poorly it’s best to place your tree at an angle in a trench and cover with soil or place it in a can. Wait to plant until the soil is crumbly and friable. Digging in waterlogged soil is one of the worst things you can do for your soil’s health.

What fruit trees can you grow here in the mountains? Well, almost everything. Most of us get 700 hours of winter chilling where the temperature is below 45 degrees. Even with climate change the chill hours add up. And we can still grow fruit like a Fuji apple that doesn’t require this much chill.

What if you don’t get full sun where you’d like to grow fruit trees? Apples, pluots and plums are good choices for an area that gets at least 5 hours of sun a day during the growing season. The ideal is full sun but these trees will still set and ripen some fruit in partially shaded conditions. With peaches, nectarines or apricots it’s a different story. These fruits need hot sun to develop sweet, tasty fruit. Too little sun and they will not deliver anything close to what you have in mind.

With a little planning you can have fresh fruit 7 months of the year. By growing your own fruit you’re not at the mercy of mechanical harvesters and shipping practices. You can grow fruit and harvest it when the time is right. Homegrown fruit is a world apart from agribusiness and much less expensive than the Farmer’s Market.

Living with Houseplants

Houseplants like Peace Lily clean the air of pollutants in your home.

I’m embarrassed to confess that I don’t always take my own advice. Take my houseplants, for instance. Decades of research have shown that houseplants reduce stress and anxiety. They can sharpen our attention, make us more productive and give us a happier outlook. They can fight indoor pollution and add moisture to the air in our homes. So why do a few of mine look so sad?

First a typical house plants lives in the understory of a tropical rain forest where it gets bright filtered light. They’re used to warm rain and perfect drainage. I’ve moved mine to the best light I have but it’s not enough for a few of them. I might have to find them better homes.

I also had a problem last year by fertilizing a little too much. I could see the edges of some leaves were brown which was probably from over fertilizing but also could have been lack of light or too much water. Skip fertilizer in December and January and start up half strength mid-February.

Water just enough to keep the soil from going totally dry allowing oxygen to move back into the root zone. Houseplants are resting at this time of year and don’t use as much water as when they are actively growing. Let the soil in a 4-6 inch pot dry half an inch down between watering then water with room temperature water. And don’t let the pot sit in a saucer of water or the roots will rot. If your plants is in a larger pot let the soil dry down a couple inches.

Don’t re-pot a plant in winter when they are slow to grow new roots. I’m really anxious to transplant a couple of mine into more decorative pots but I’m going to hold off until March.

Plants that I have had good results with in lower light are philodendron, peace lily, Chinese evergreen, cast-iron plant, schefflera, arboricola, ferns and palms. Hanging plants that grow well in low light are hear-shaped philodendron, pathos and grape ivy. Most of these house plants grow naturally in low light areas of the jungle. Don’t overwater and they’ll be happy.

So far, this winter hasn’t been as rainy as last but still it’s been cold and my home is closed up to keep the heating bill down. Without doors and windows open to circulate fresh air, toxins such as benzene, formaldehyde and trichloroethylene can be realized from furniture upholstery, carpets, cleaning products, paint, plastics and rubber can build up inside. Carbon monoxide from the incomplete burning or wood and vehicle exhaust can also be present in indoor air.

Biological pollutants include bacteria, viruses, animal dander, house dust, pollen and dried cat saliva. What? Cat saliva? Do you hear that Archer? House mites, the source of one of the most powerful biological allergens, grow in damp warm environments. Mold and mildew grow in moist places like central heating systems and are just one more source of indoor pollution.

NASA researchers suggest that the most efficient air cleaning occurs with at least one houseplants per 100 square feet. Even the microorganisms in potting soil removes some toxins.

Some of the easiest houseplants to grow are some of the best to have in your home. Any of the plants listed above would fit the bill. If you have a cat or dog that nibbles, however, it’s best to stick with spider plants, palms and orchids, African violets, aluminum plant, bromeliads, peperomia, cast iron plants, Christmas cactus, chenille plant, creeping Charlie, false aralia wandering jew, piggy back plant and succulents like donkey’s tail and echeveria.

With a little planning you can clean the air in your home while keeping the pets safe.