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.
climate zones

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.

allergy-free gardening

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.

bare root plants, fruit trees, planting bare root

Edibles & Ornamentals – The Bare Root Way

Autumnalis flowering cherry

It?s been a weird winter, weather-wise, but aren?t they all one way or another?? My flowering plum is blooming weeks early. I have an Autumnalis flowering cherry tree that blooms several times a year. The last blooming cycle started in late November and it?s still blooming now. This tree came into my life 20 years ago as a bare root tree. We?re old friends. Now is the time to add ornamentals and edibles like fruit, nuts, berries and vegetables while they?re available in bare root form. They are easy to plant, economical and establish quickly.

Shop for your plants in January or February while they are still dormant. Once leaves emerge or flower buds start to swell, roots have already started growing. You want your tree to start developing new permanent roots in their final home. Stone fruits such as apricots, peaches, plums and cherries are going to start waking up first so they are best put in the ground soon. Fruit trees like pears and apples wake up later so you can wait a bit longer to plant those varieties.

apple ready to eat from a bare root tree

What fruit tree varieties can you grow here in the mountains? Well, almost everything. Most of us get 700-900 chilling hours per winter. What does that mean? Well, many fruit trees, lilacs and peonies need a certain number of hours during dormancy where the temperature is 45 degrees or less. You can give the plant more chilling in the winter but not less. Those in coastal Santa Cruz can grow Fuji apples as they require only 300 hours of chilling but not Red Delicious. We can grow both.

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 some sun- at least 5 hours 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.

Bare root fruit trees at Mountain Feed & Farm Supply

What?s the correct way to plant a bare root tree? According to research amending the soil is no longer recommended. Mountain Feed & Farm Supply in Ben Lomond has a great web site with all the information you need to get your new fruit trees off to a good start including pruning, staking, mulching and care as they mature.

Don?t plant in heavy saturated soil with a high clay content, however. If your soil drains poorly it?s best to place your bare root tree at an angle in a trench, cover with soil and water in. Wait to plant until the soil is crumbly and friable with plenty of pore space. Digging in waterlogged clay soil is one of the worst things you can do for your soil?s health.

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.