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.

What Makes for a Sustainable Garden?

The redbud are just starting to show color in my yard. Flowering plum, tulip magnolia, manzanita, forsythia, flowering currant and quince are blooming in many a garden. Even the deciduous trees and plants that look bare now are starting to grow new roots deep underground. It’s time to plan this year’s garden. Think about how you can blend artistry with ecology.

Garden to attract birds, bees, butterflies and other beneficial insects

A landscape developed with sustainable practices will improve the environment by conserving resources. It will require less maintenance and fertilizing, be balanced with our climate in mind and use less pesticides and water. Most of all it will be visually pleasing with lots of flowers. bees and butterflies.

Your goal may be a more drought tolerant garden but which plants are right for your yard? What plants will be more likely to withstand disease and pest damage? What kind of irrigation system should be installed to provide for the needs of the landscape in the most efficient way possible? Is it time to convert your sprinkler system to smart drip, inline drip emitters and micro-irrigation?

Where do you put the compost bin so you can return garden waste and kitchen waste back to the garden while recycling nutrients within the landscape? How do you keep the soil healthy? There are many components in designing and installing a sustainable landscape that is just right for your garden.

Start with a smart design. Utilize permeable paving like gravel or pavers to help manage runoff, giving the soil more time to absorb rainfall and recharge the ground water. Maybe you need a rain garden or small planted basin to catch and filter rainwater and keep it onsite.

Planting bed of plants with similar watering needs.

Group plants in your garden according to their water needs. Now’s the time to transplant if necessary to achieve this. Some maybe can survive on rainfall alone after their second or third season while the perennial beds and vegetable garden will require a different schedule. Water slowly, deeply and infrequently so there is no runoff. Water in early morning or evening to maximize absorption.

Plant deciduous trees to provide cooling shade in the summer and allow sunlight to warm the house in winter. Trees and shrubs clean the air of nitrogen, sulfur dioxide, ozone and carbon monoxide. They breathe in carbon dioxide, a major greenhouse gas, use the carbon to grow, then exhale oxygen. They retain more carbon than they lose so every tree you plant helps reduce your carbon footprint on the planet.

Feed and shelter birds, butterflies and other wildlife in your landscape. Plant perennials such as echinacea, lavender, penstemon or salvia, ceanothus and other native plants to attract pollinators like bees and hummingbirds. Plant flowers that attract beneficial insects to help control harmful insects and use organic pesticides.

Make your soil a priority by adding compost each year. Mulch your soil to keep down weeds and conserve water and use organic fertilizers, manure and fish emulsion that feed the soil. Compost the green and brown waste your garden produces like fallen leaves, weeds without seeds, grass clippings, spent flowers and vegetables.
Stay ahead of weeds, pulling them before they set seed and spread.

Take steps each year to encourage a beautiful, sustainable landscape and make your corner of the world part of the solution.

Choosing & Growing Flowering Dogwoods

A couple weeks ago in a column about allergy free landscaping, I mentioned dogwood being a good tree choice as their pollen is not wind borne. Their showy flowers are pollinated by insects rather than by the wind. Producing less pollen, their pollen is large and heavy, sticking to insects rather than becoming airborne and leading to sneezing, runny noses and watery eyes. With dogwoods about to burst into bloom I thought I’d share some information about growing this iconic tree.

California native cornus nuttallii

There are four main species of dogwood trees. From the Himalayas in China comes cornus capitata. Korea is home to cornus kousa. Cornus florida is native to the east coast and the west coast is home to cornus nuttallii or the Western dogwood.

Our native Western dogwood is unfortunately prone to leaf spot fungal diseases. Their large snow white flowers are especially brilliant along the shady forested roads along Yosemite valley. They are a little temperamental in the garden before they reach the age of 10 years but after that they tolerate seasonal flooding, flower and grow fine with little care.

Eastern flowering dogwood

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. 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.

Cornus capitata ‘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.  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. 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.

Dogwoods attract a variety of wildlife. All sorts of critters use this tree for food and shelter. The giant silk moth and several species of butterflies favor dogwoods as host plants. The spring flowers provide nectar to bees and other pollinating insects. Robin and sparrow are just two of the bird species than build nests on the horizontal branches and many others seek shelter in the leaves. The high calcium, high fat, fleshy red fruits are eaten by 35 species of birds including titmice, juncos and waxwings. They are edible but bland and tasteless to us. Birds love them.

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 4:00 PM. Add a couple of extra drip emitters or inline drip tubing to your irrigation system and they’ll be happy.

Gardening 101 – Climate Zones

You can tell right away when you walk out the door how hot or cold it is, how windy, shady, moist or dry. You know if your soil is pure sand or hard clay because you’ve dug a few holes in your time. You don’t need a book to tell you these things. So why are the gardening zones described in Sunset Western Gardening book important when you add a new plant to your garden? And why are they so confusing in our area? The USDA Plant Hardiness zone map may tell you where a plant may survive the winter but climate zone maps let you see where that plant will thrive year round.

Mixed forest Bonny Doon- zone 15

For decades, climatic data has been complied and maps generated to help make sense of local growing conditions. In the 1930’s, Sunset Magazine began mapping the western states, taking into consideration the unique climatic growing conditions along with the traditional data of minimum and maximum temperatures, latitude, elevation, ocean influence, continental air influence, mountains, hills and the local topography.

Today the map has become known by many as the gold standard for western growing advice. Zones are numbered from the harshest (Zone 1) in the north to the mildest (Zone 33) in the south.

To accompany the map a plant encyclopedia was developed that assigned the appropriate zone(s) for each plant. The system helps take some of the guesswork out of plant selection if you take into account your microclimate.

The zone system isn’t perfect. After all, the data collectors don’t live here in our neck of the woods. Still, it’s a good idea to take a look at the Sunset zone you live in to see if a plant might survive in your garden – if you keep these exceptions in mind.

Light dusting of snow in February 2018- Bonny Doon

We really only garden in two zones around here – zone 15 and 16. The Sunset map erroneously shows Felton as being in zone 7. Based on my experience even ridge tops like the highest portions of Bonny Doon and the Summit area which gets an occasional dusting of snow fall mostly in a colder zone 15.

Zone 15 – this zone encompasses most of our area. Winter lows average 20-30 degrees although we are trending toward warmer winters these last few years. The valley floor of both San Lorenzo and Scotts Valley lie in this zone and are what I call “a cold 15”. Cold air sinks and is trapped in these areas. There are warmer parts of this zone, though. These areas rarely get a freeze after March 15th or before Thanksgiving.

Zone 16 – those who live up off the valley floor but below ridge tops live in this “banana belt”. Light frost can occur during the winter but mostly the winter lows in this zone stay above freezing.

Ceanothus near Felton Covered Bridge, a cold area near San Lorenzo River.

Beside the zone you also need to note how much sun or shade you get during the growing season. There may also be microclimates on your property. And soil quality is not taken into consideration in zone mapping. Since the soil houses the water and nutrient uptake system for most plants, it plays an important role. Most plant guides describe soil requirements in terms of well-drained, acid or alkaline, poorly drained or high organic matter.

If you have questions about which zone you are in, email me and I’d be happy to help. I hope this helps in choosing plants that will thrive in your garden.

Planting for the Allergry Sufferer

Each day my windshield is coated with yellow pollen grains from Douglas fir trees. Roadsides are crowded with blooming acacia trees. If you’re an allergy sufferer some plants are worse than others for you. What’s a gardener to do to mitigate scratchy eyes and congestion nearly year round where we live?

Blooming Acacia tree- pollen not airborne

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.

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 pollens can travel many miles, the majority tend to stay in the general area of their origin.

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”s property 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.

Dogwood with sneezeless flowers

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 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.

Hopefully, our lack of rainy weather will not cause problems for allergy sufferers. Symptoms may become worse 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 sneezeless spring for you allergy sufferers.

Pruning Plants in February

My plants are confused. Actually they know exactly what they are doing it’s me that’s confused. The mild winter, so far at least, has encouraged many of my plants normally still dormant at this time of year to start growing for the season. What’s a gardener to do when the roses, fuchsias, oakleaf hydrangeas and many other plants never really went dormant this year? Here are some February tasks that I’m going to be doing.

Cut back woody shrubs to stimulate lush new growth. Trim plants like Mexican bush sage and artemisia to within a few inches of the ground. Don’t use this approach on lavender or ceanothus, though. Lightly prune those after blooming later in the season and don’t cut back to bare wood inside the plant.

Prune fuchsias back by a third and remove dead, crossing branches and interior twiggy growth. Container fuchsias can be cut back to the pot rim. Do this right away if you haven’t already done so. A plant is wasting energy on new growth just to have it trimmed off later.

Cut back hydrangeas stems that bloomed last year and apply a soil acidifier if you want the flowers blue. Although aluminum sulfate is the traditional favorite for quickly acidifying soil it’s not as kind to beneficial soil microorganisms. Coffee grounds, pine needles, peat moss and cottonseed meal are better for your soil.

Miss Kim lilac

Don’t prune spring flowering shrubs like lilac, weigela and spirea or flowering trees such as cherry, plum and crabapple now. These and evergreens like rhododendrons, azaleas and camellias should be pruned after they flower. You can cut some branches while they are blooming to bring into the house for bouquets.

Even if you have pruned your roses be sure to remove old leaves still clinging to the plant even if the leaves look okay now. They will most likely develop fungal spots and diseases later if you don’t. Rake up any debris beneath the plant and discard to eliminate overwintering fungus spores

Roses are super forgiving and you can trim them up again using the following guidelines. The goal is to produce lots of roses not just a few of exhibition size. Aim for a vase-shaped bush with an open center.

Prune old garden roses that bloom once in the spring after flowering. Climbing roses require little pruning. 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 cause the cane to flower along its complete length for a beautiful spring display.

Wait to prune back perennials that may have their new foliage damaged in a late frost. Same goes for shrubs that might have gotten hit by frost. That damaged foliage can protect the plant from further frost damage. Mid-March is the estimated date of hard frost in our area or at least it used to be. We gardeners are always betting Mother Nature will go our way and our efforts will not have gone in vain.

Prune fruit, nut, shade trees and deciduous vines like clematis.

Cut back ornamental grasses if you live where you rarely get frost. I’m pruning California fuchsia, salvia ‘Bee’s Bliss’ and hummingbird sage now. They look okay now but I want the encourage new, compact growth.

Flowering Plants for Wintertime

Daphne odora ‘Maejima’

I had to wait a couple years for my variegated winter daphne to settle in before setting flowers but this year it’s making up for lost time. There’s something special about a plant that will bloom in the depth of winter, hold up to rain and scent the garden all at the same time. With beautiful rosy-pink flower clusters and attractive yellow-margined variegated foliage, daphne make a great foundation plant for dappled shade gardens. They are deer resistant and have low water requirements during the summer. What’s not to love?

Tagetes lemmonii

Yellow is always a cheery color in the garden at any time of year. The deep golden flowers of Mexican marigold or tagetes lemmonii are carried on branch ends sporadically all year, peaking in winter and spring. Finely divided leaves are strongly fragrant when crushed and smell like a blend of marigold, lemon and mint which is why deer avoid them. Prune them lightly to control shape and size. They grows 3-6 ft tall and as wide.

A favorite of birds and indoor floral arrangers is the evergreen mahonia. They are already blooming with cheery, bright yellow flower clusters that will last for months. When each flower sets a purple berry they look like grape clusters. The edible berries make good jelly, too. There are 70 varieties of mahonia including our own native Oregon Grape which grows in the understory of Douglas fir forests. Mahonia aquifolium is resistant to summer drought, tolerates poor soil and doesn’t create a lot of leaf litter.

Helleborus orientalis

Also here in my own garden the hellebore flowers are holding up well. One of my favorites is called Cinnamon Snow but all of the varieties of this buttercup relative accept wind, rain, cold and less than perfect soil while getting by with only moderate watering in the shady summer garden. Deer aren’t attracted to them either.

Recently, after seeing a Pink Australian Fuchsia blooming so profusely despite the rain, I decided to add a variegated variety called Correa ‘Wyn’s Wonder’ to my own garden. Although not related to hybrid fuchsias, the flowers are similar and their nectar will feed the Anna’s hummingbirds. They grow well in dry shade under oaks are deer resistant and drought tolerant.

Camellia sasanqua

Camellia flowers, thick, tough and full of color, easily sail through winter weather. Camellias bloom for a long time and with so many types you can have one blooming from October all the way through May. This showy evergreen shrub is quite drought tolerant once established. Yes, with some mulch and and a deep soak every so often they require much less irrigation than you’d think. There are even fragrant varieties, such as Pink Yuletide, a sport of the popular red Yuletide.

Pieris japonica variegata

Another tough plant that can take weather extremes is the Lily-of-the-Valley shrub (Pieris japonica). There are many varieties of this early winter bloomer. Some have pure white flowers, other sport various shades of pink or dark rose.
Mine is the smaller variegated foliage model with dainty, drooping clusters of pure white flowers in early spring. Right now it is covered with flower buds so dense that you’d think it was already blooming. The new growth in the spring has a beautiful pink tint. This shrub will hold up to the wildest weather. Another plus for the Lily-of-the-Valley shrub is that is useful for firescaping in the landscape and it isn’t on the menu for deer either.

Other winter blooming plants include abutilon, euroyops, witch hazel, edgeworthia, michelia, loropetalum and grevillea. Driving around I’m seeing that the Saucer Magnolia’s are putting on quite the show this year.