Master Gardener News Blog
By Linda Lewis Griffith
Poison oak is native to western North America and is widely distributed throughout San Luis Obispo County. Poison oak can be difficult to identify because it grows in a wide variety of habitats and looks different depending on its location. In sunny, open areas, poison oak forms a dense, leafy shrub that stands 1 to 6 feet tall. In shaded areas, such as creek beds or oak woodlands, it becomes a climbing vine, supporting itself on other vegetation or upright objects using its aerial roots.
Leaves normally consist of three leaflets with the stalk of the central leaflet being longer than the other two. Each leaflet is 1 to 4 inches long and smooth with toothed or somewhat lobed edges. The surface of the leaves can be glossy or dull and sometimes even a little hairy. In winter the leaves drop off. The diversity in leaf size and shape accounts for the Latin term Toxicodendron diversilobum, meaning poisonous tree with many shaped lobes.
Poison oak is considered the most hazardous plant in California due to the annual number of working hours lost from allergic contact dermatitis after touching the plant. The allergic reaction occurs in 80 to 85 percent of the population and can lead to skin irritation, itching, and blisters. Transmission of the allergen can occur by direct contact with the plant at any time of the year. It can also happen by touching contaminated clothing, tools or animals, or by breathing the smoke of burning poison oak.
You can remove poison oak in your yard by physically pulling it out or grubbing with a shovel or pick. It's important to take out the entire plant, including the roots. Remove plants in early spring or late fall when the soil is moist and it is easier to dislodge rootstocks. Grubbing when the soil is dry and hard usually breaks off the stems, leaving the rootstalks to vigorously resprout. Detached and dried brush can still cause dermatitis, so bury or stack the plant material in an out-of-the-way location, or take it to a disposal site.
The Dreamy Echium
By Andrea Peck
If you are looking for a plant that belts out Wonderland, Romance and Fairytale in melodic unison, look no further than the Tower of Jewels (Echium wildpretii ). Two years ago, I took a chance on this homely little tike. It had grey-green, triangular-shaped leaves and sat in a slumped sort of way in the pot. It looked like a whole lot of nothing. But, the description, along with a picture taped up above the display, prompted me to spend the $3.99 required to bring the 4” container home.
I planted it out in the middle of what should probably be called my personal garden wasteland, but we'll just call it the front yard. It didn't do anything for two years. It did not die. It did not grow significantly. Its shlumpiness got a bit more pronounced, but that did not seem promising. I was not hugely disappointed because I tend to be unconfident when it comes to new plants. Who was I to expect that this beautiful creature would make an appearance in my yard anyway? Just another waste of $3.99, I thought.
But, this year it blew me away.
I'm a little fuzzy with the months, but I want to say somewhere in May and June it grew to gigantic proportions. It was mammoth and dramatic. I'd peek out into my yard and swoon over it. The flower spike was large (about 4 feet) and conical, with masses of tiny pink-red flowers. The Tower of Jewels moniker is hardly an exaggeration --you half expect it to turn into some exotic princess or mystical sprite. Even the way it leans and curves its massive octopus-like appendage is charming.
The plant is native to the Canary Islands and was at one point an endangered species. Efforts to save the magical beast have paid off, however. Echium is habituated to a dry climate, making it drought-tolerant. It does not fare well in frost, particularly conditions below 20°F. It grows best in fast draining, rocky soil. Cactus soil is a good choice. It can be grown successfully in a container, but it will need irrigation to prevent drying out. It does not need fertilizing.
To be honest, photographs do no justice to this plant. You really must see them in 3-dimensions. Not only is the plant spectacular in the sunlight, but it teams with life as bees buzz around it and hummingbirds hastily spiral from flower to flower.
Sometime around July my plant started to shrivel like the Wicked Witch's legs in the Wizard of Oz. Death was imminent. Of course, I did not have time to extricate it from my yard as we were in summer-mode. Luckily, I left it, because I learned that the Echium, though considered an annual, drops lots and lots of seeds.
It still reclines in my yard, a pile of gray matter that looks something like a long tube of gray ash. I'm not moving it—no way.
I'm hoping for a forest of them next year.
By Tami Reece UCCE Master Gardener
The 9th Annual Tomato Extravaganza will feature informative workshops, a plant sale, the very popular tomato and basil tasting, and much more! The Master Gardeners will gather 15 to 20 heirloom and hybrid tomato varieties from local farmers and have grown 10 different varieties of basil for this year's tomato and basil tasting.
Heirloom tomatoes will be available for purchase, but if you want to grow your own, there are over 7,500 varieties of tomatoes on the market and they do love sunny California. However, several varieties are well-adapted to less sunny conditions. Black krim grows very well along the coastal areas of San Luis Obispo County. North County has the opposite problem - too much sun. The optimal temperature range is between 55 and 85 degrees Fahrenheit depending on the variety. Heirloom tomatoes come in shades of red, green, orange, pink, white, blue, yellow, and purple. They can be a solid rich color, striped or mottled. They can be larger than the palm of your hand or as small as a cherry or grape which is also the name of two varieties.
There are between 50 to 150 different varieties of basil available on the market. The colors and flavors of basil continue to expand as growers cross different varieties to create new basil plants each year.
If you have only known the common red tomato and green Italian Basil, join us to experience the many flavors and colors that are available. The Tomato Extravaganza is on Saturday August 29, 10:00 to 2:00 p.m. We are located at 2156 Sierra Way, San Luis Obispo. The presentations will begin at 10:00 am with Water Catchment, Gopher and Ground Squirrels at 11:00, and Edible Landscaping at 12:00. The plant sale will feature Mediterranean plants, herbs, and basil, and the California Rare Fruit Growers will be on hand selling trees. Children's activities and displays will be available and a locally owned food truck will be on site from 11:00 to 1:00. Spend the day with us or stop by to see our beautiful demonstration garden. Either way you will not be disappointed!! For more information, visit http://ucanr.edu/sites/mgslo/files/218081.pdf or call (805)781-5939.
The Germane Geranium
By Andrea Peck
When I mentioned to my mother that I might write about geraniums this week, she paused distractedly as she crossed the road and stated, “Isn't that a bit boring?”
While there was a brief moment in which I personalized this comment, I quickly realized what she meant. The fact is geraniums don't have the most exciting reputation. Though I do associate them with attractive window boxes on the exterior of cute French homes and I think that France is definitely high on the interest scale, this is a plant that is often overlooked.
As the conversation wound on, there was a discrepancy between the how much water a geranium requires. According to my mother's neighbor, geraniums require a lot of water. I did a double- take at this and was rewarded when we glanced out into the weed-spackled lawn. On the side of the lawn, there was a section set aside for ornamental planting. Most of these plants had long died due to drought. A rectangle of barren brown earth sat empty, but for one sole survivor. No doubt the impenetrable hardpan, out of which poked one or two resilient weeds did not help nurture those long-gone plantings. But, what still survived, sturdy and blooming? Yes, of course, a nice red geranium bush.
Odd though, how you can walk past that bush and see just the dead-looking soil surrounding it. They are quite the invisible plant, able to stand, solid and stoic, all the while completely underappreciated. I have my own geraniums. They rest in two pots right outside my front door. I see the beauty that they add, the color, but my eye never really resides on their form for long.
Nevertheless, everyone should have a geranium or two in my opinion. They are quiet workhorses and unless you live in inhumanly hot weather (which some of you do, I know) then they require little additional water. A bit of a drink here and there and they will keep their form.
Geraniums are represented in such a wide variety of colors and types. From white or pink to red and purple to blue, they are a nice low-growing perennial. The great thing about geraniums is how easy they are to propagate. Simply cut off a stem and plant it. Keep it watered adequately at the beginning and it should settle in just fine. They are also deer-resistant. Geraniums flower quite a bit, so it is necessary to prune off dead flowers to keep the plant looking fresh.
My mother's parting shot, one to remember, is that she feels as if she is cheating by having a geranium. They are just that easy.
Walnut Tree M.D.
By Jutta Thoerner UCCE Master Gardener
My large walnut tree has many dead branches this year, can it be saved? Tom in Paso Robles.
If you drive by the walnut and almond orchards in Paso Robles, many dry farmed for centuries, you will notice the same problem. The last four years of drought have left their mark by killing branches in the canopy. This “die back” is generally not reversible, especially if the trees are older. Walnut trees will near the end of their productive life after 40 years. If you see less than 20 % die back, you can prune back the dead branches until you get to the green living part of the tree. This should result in new branch growth the following spring. Most arborists advise you to prune during the dryer months of the year to prevent the spreading of fungal diseases. You can mark the dead areas by attaching some tape to it so you can distinguish the dead from the live wood once all the leaves have dropped.
Monitor the health of your trees by checking for insects; walnut husk fly and codling moths will deposit their eggs in the nut meat, scales and mites will affect the vigor of the tree. Check for small holes in branch and bark tissue to monitor for the presence of boring beetles. Contact the Master Gardener Helpline for assistance with the identifying any of these or other pests.
If you have determined that the age of the tree and the amount of die back warrants the removal of the tree, get the site ready now for next year's replant. If a total tree and root removal is not an option, cut the tree now and leave the stump to dry out for the rest of the year. You can replant a new tree in January or February when bare root trees become available. Most walnut trees in the nursery are already grafted and many new varietals are now available. Since walnuts are wind pollinated, planting just one tree is an option if there are other walnut trees in your neighborhood.