Daily Archives: October 21, 2009

California Native Plants, Sudden oak death syndrome

El Nino & SOD

Leave a comment

 Recent rainfall may have you thinking that El Nino conditions are indeed strengthening as NOAA has predicted and that this will be a wet winter. California does not always see an increase in precipitation, however,  during El Nino years but we can always hope and be prepared.

Here’s why. Every 2-7 years the trade winds in the warm equatorial waters of the Pacific Ocean slacken, or sometimes even reverse direction, and warmer-than-normal water accumulates along the equator in the central and eastern Pacific. This warming is called El Nino, because its effects are greatest in the winter and often disrupt fishing along the So. American coast around . Equatorial water is averaging one degree warmer so far this fall and should continue to warm. If it averages 2.5 degrees warmer, that’s a moderate El NIno. If it goes higher that would be considered a strong El Nino. During the biggest El Nino winters in 1997-’98 and also in 1982-’83, Pacific waters reached nearly 5 degrees warmer.  The winter of 1997 brought nearly 90" of rain to Boulder Creek and in 1982 we had 111" of rain.  Interesting to note, however, that the strong El Nino of 1991 only brought 46" of rain to our area.

The El Nino now under way doesn’t guarantee our area will receive drenching winter rains, but the stronger the condition and warmer the water, the greater the likely hood.

If you have oaks or tanoak trees on your property, a wet El Nino winter makes conditions perfect for the spread of Sudden Oak Death (SOD). The pathogen that causes this disease thrives and spreads in moist, mild climates. There is no known cure for SOD, the only way to protect susceptible oaks and tanoaks is preventative treatment before conditions for infection are optimal.

To arm trees with as much resistance as possible, treatments must be applied in the fall and again in the spring. There is a free training session given by the Calif. Oak Mortality Task Force in Berkeley on Nov 4th and Dec. 9th. This training session as well as information on their web site   (   www.suddenoakdeath.org  )  will help you gain information about how to select candidate trees for treatment and proper preventative treatment applications.  
 
We have seen the effects of SOD on the oak trees in our own area.  Since the mid 1990’s over a million oak and tan oak trees have died throughout California. Preventative treatment is the key to slowing the spread of this pathogen and to protect high value individual trees at risk of infection.

Laboratory testing is the only way to confirm this disease.  You cannot diagnose symptoms solely by eye as many diseases look similar. You can view photos at the web site to compare symptoms with those on your oak or tanoak trees. Also look at nearby Calif. bay laurel, rhododendrons or camellia plants with spots on their leaves as this could possibly by correlated.  If you suspect you have infected trees you can get the leaves tested at our local AG Extension in Watsonville.

The treatment approved by the State of California against phytophthora ramorum infection is Agri-Fos, a phosphonate compound. It is best used as a preventative measure and is not a cure. It can help protect trees from getting infected and mays suppress disease progression in very early infections. Sprayed on the trunk or injected into the tree it takes 3-6 weeks to be assimilated and become effective.

Generally, you should treat high value oak trees within 150 ft of other infected trees or plants. You may want to treat healthy oaks or tan oaks if they are surrounded by healthy bay laurel and there are know infections within 1000 ft. I could not find a local source for Agri-Fos but you can buy it directily through them.  There is a link on the above listed website.

Education is key to slowing the spread of SOD and protecting high-value individual trees at risk of infection.
 

 

Flowering trees, garden design, trees

How to have a Sense of Place in your garden

Leave a comment

Recently I got to enjoy this beautiful October weather walking among the redwoods, mixed oak woodland and open fields watching hawks soar overhead and listening to migrating warblers in the trees.  I was not here in Santa Cruz county, however, but Pt. Reyes National Seashore-a similar but different environment. What struck me was how the gardens of the local residents reflect where they live.  There was a sense of place to the landscaping. 

Our gardens reflect where we live, too.  What can we learn from our surroundings that will help us in our own gardens?

Look to the horizon.  Check views from every possible angel. Borrow scenery if it’s attractive or screen eyesores and distract the eye from them.

Highlight existing features. Develop designs that retain and enhance elements on site like interesting rock formations, meadows, existing trees and native woodland plants.

Consider all aspects of your outdoor space. What are your favorite flower and plant foliage colors?  What patio materials do you like -flagstone, wood, gravel, pavers? What is your favorite season- spring flowering trees and bulbs or fall foliage and berries?  How many hours do you spend enjoying the garden-  sitting, reading, working, relaxing or entertaining?

Whatever landscape design elements you use in your garden, remember they can be broken into smaller parts to make them more manageable- paving this year, planting trees next year, then shrubs, perennials, garden art. Installing a garden is about the journey.  There is never a finishing point.

Important in any design is your choice of trees. More than any other living feature in your landscape, trees contribute to your sense of place. Imaging how different this area would look without the redwoods, spreading oak trees or tall ponderosa pines.

A tree that looks good and thrives in many types of gardens while requiring little summer water once established is the Strawberry tree or arbutus. A relative of the madrone, this evergreen tree is interesting year round. In the fall and winter, clusters of small white or pink, urn-shaped flowers hang from rich, reddish-brown branches with shedding bark. Fruit resembling strawberries ripen in the fall and attract birds. The handsome glossy green leaves emerge from red stems and contrast nicely with the bark, flowers and berriies. Growing to about 25 ft tall they accept full sun or part shade. What’s not to love about a tree with ornamental bark, dainty flowers, decorative edible fruit and handsome foliage?

Another tree to dress your garden for fall is Prairifire flowering crabapple. Birds love the berries and the 1/2 inch fruit remains on the tree for a long time after leaves drop providing food well into winter.  Many of the popular crabapple varieties of the past were highly prone to fungal diseases but this one is among the new disease- resistant varieties now available. Prairifire bloom later than most crabapples with long lasting bright red flowers. Even the red leaves lend color to the garden when they emerge in the spring. If your looking for a small 20 foot ornamental tree with spring flowers and fall berries, this is a good choice for your garden.

Let your landscape express a sense of place to your garden.