- Author: Andrea Peck
- Editor: Noni Todd
Asian citrus psyllid
By Andrea Peck
My intended focus of discussion this week was the writhing mass of maggots that took up residence in my compost bin for two days, but it turns out a more dire circumstance may be brewing in SLO County.
On March 26, 2014 the notorious Asian citrus psyllid was found in a trap disguised as a floating campsite in Arroyo Grande. The free loader was alone.
The Asian citrus psyllid (ACP), Diaphorina citri, is a small, winged insect, brown in color and approximately the size of an aphid. It typically feeds on citrus trees such as oranges, grapefruit, lemons, and mandarins and a few very closely related ornamental plants in the family Rutaceae (e.g., calamondin, box orange, Indian curry leaf, and orange jessamine or orange jasmine).
The ACP feeds on new leaf growth, leaving the young leaves twisted and curled. New shoots are often lost in the process. But, it is not this feeding habit that is the biggest concern. It is the disease that the ACP transmits. The insect is a vector of the bacterium Candidatus Liberibacter asiaticus, associated with the citrus disease huanglongbing (HLB), also called citrus greening disease. HLB causes leaves to yellow and the fruit to be bitter, hard and misshapen. The inevitable death of the tree occurs in as little as five years. The psyllid can pick up the bacterium when feeding on an infected tree. Once the ACP is infected with the bacterium, it will be a carrier for the remainder of its life and can transfer the disease when feeding on other trees.
In the United States alone, consumption of oranges is higher than that of any other fruit. California is one of the top four citrus producers in the country and the top seller of lemons. The lemon industry in California is valued in the upper $3 million range. With so much at stake it is understandable why concern is at its peak – especially amongst the agricultural community.
Due to the severity of the problem, the USDA has created a new Multi-Agency Coordination (MAC) Group, or emergency response group, to address HLB.
Locally, the Arroyo Grande area is under a mandatory quarantine to within a five mile radius while state and local officials determine the extent of the invasion. This quarantine may be extended in the near future.
Checking your trees at home is not only important for your own garden, but the fate of the commercial industry. Check all citrus trees thoroughly, especially the underside of leaves and areas of new growth. Adult ACPs have a sleek, aerodynamic shape and are known for their distinct feeding habit; the insect appears to be latched on head first into the plant material and its tail end is raised into the air. The nymphs exude a characteristic waxy, white substance that hangs from leaves in a corkscrew-shaped manner. Images abound across the internet – but remember even one insect is cause for alarm and should be reported.
Citrus plants, material or fruit should not be transported outside of quarantined areas. Purchase trees from reputable, licensed California nurseries. When disposing of tree clippings, dry or double bag prior to disposal.
Click here for a map of the quarantine area.
Find more information and photos on the UP IPM and UC Riverside websites - http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn74155.html
Call 1(800) 491-1899 if you suspect your tree has been infested.
Don't forget ! There will be a plant sale of drought tolerant, Mediterranean plants after the June ATGB.
Calendar of upcoming ATGB workshops:
- Author: Lee Oliphant
- Editor: Noni Todd
Saving Garden Water In April
By Lee Oliphant Master Gardener
Q. March rains brought my garden to life. Other than the usual cleanup and weeding, what needs to be done this season of the year? Nancy W., Cambria
This year will be challenging for gardeners. It appears that water restrictions will continue throughout the county as we progress through our third year of drought. Planting will take a back seat for most of us. Keeping our existing plants alive will become a priority. Many of us live in communities that have mandatory restrictions on outdoor irrigation. Gardeners are becoming remarkably creative in finding ways to obtain, transport, store, and utilize non-potable water for landscapes.
If you're planning on adding new plants, choose Mediterranean plants that require little summer water once established. Remember, even drought-tolerant plants need some summer water until they become established. If you must add colorful plants to satisfy your summer need for vibrant color, consider Gaillardia (blanket flower), Rudbekia (coneflower), penstemon, yarrow, agastache, perennial geranium, daylilies, lavender, red-hot-poker, Russian sage, and lavender. These plants can survive years of drought with minimum supplemental water.
There are veggies that are considered drought tolerant. Many common varieties of zucchini, kale, and believe it or not, tomatoes need little water to produce. Herbs such as sage, rosemary, hyssop, lavender, oregano, and thyme are also drought-tolerant.
Tips for drought tolerant vegetable gardening:
- Plant vegetables early this year. Choose plants that grow in cool weather. Summer plants take more water. Plant chard, kale, and arugula now.
- Plant drought tolerant varieties like ‘Dark Star' zucchini and stupice tomatoes.
- Double the depth of beds so that roots will be able to reach down where the soil is moist.
- Dig in more than the usual amount of compost to hold water.
- Remember to mulch the soil as you would your landscape, to a depth of 3-4”.
The drought will test our determination to continue our love affair with our gardens. Continued success in gardening will depend on our willingness to research and experiment with “water with less” approaches in California.
Find more drought information resources online at http://cesanluisobispo.ucanr.edu/
- Author: Andrea Peck
- Editor: Noni Todd
Field Trip!
By Andrea Peck
Show me your garden and I shall tell you what you are.
- Alfred Austin
Oh, Mulch! You say?
You've heard enough of rain barrels and water conservation? Does the drought leave you dizzy as you decide between your hose and your water pail? Or maybe you're convinced that a large project is in your future. Rainwater garden or swale, anyone?
Maybe it's time to get out for a field trip to see the real thing. Today I decided to do just that and take advantage of the new docent hours to check out the garden in detail. There's nothing like full color in 3-dimensions to solidify what you've been reading about. The UCCE demonstration garden, officially known as the Garden of the Seven Sisters, is a great place for interested gardeners. It's small enough to make your way around, yet packed with every garden variation. Located at 2156 Sierra Way in San Luis Obispo, the Garden of the Seven Sisters sits on a gently sloping field that began with a bunch of weeds, hole-digging critters and a big, mysterious tree. The past four years have seen a transformation as hard-working Master Gardeners have brought the otherwise neglected land into full bloom all while utilizing the natural slope of the property.
Not only does the garden feature a variety of garden designs, such as lawn alternatives, drought tolerant ornamentals, raised beds and a children's garden, it also contains a large rain barrel, two garden sheds, a rainwater garden, retention basin and an orchard that more often than not, contains two or three trees in one hole. The slope, originally a difficult feature of the garden, was turned into a strength as planning took over. According to Cindy Horney, the main organizer of the rainwater garden, the rainwater garden ended up larger than typically necessary because of the advantage of the slope, which, she says, made deep digging less of a concern. This may be something to think about when considering placement on your own property.
The route that the water travels is interesting, to say the least. I had to ask Cindy at a number of points – where does the water go, exactly? How does this work? If you are trying to follow the “water trail,” the best place to start is at the two garden sheds. Then look up. From that vantage point, you will see the rain gutters and piping that feeds rainwater into the rain barrel. Water that overflows the rain barrel runs through a pipe into a trough that has a pipe which goes underground, below the stairs and pathway. This pipe then feeds water into the rainwater garden.
The rainwater garden is planted with a mix of appropriate plants which need irrigation during dry patches. (For a list of plants, follow this link: http://ucanr.edu/sites/mgslo/files/147107.pdf ). The rainwater garden is meant to hold quite a bit of water, but an overflow plan is a necessity. Water that overflows follows another pipe, under the pathway and is slowed by a curving, rocky swale. This water percolates into yet another pipe, underneath another pathway, into a retention basin. The retention basin holds the water for further percolation.
Each component of the garden, from vegetable beds, succulent gardens, rainwater containment and fruit tree plantings are constructed and planted in a manner that can be replicated in the average homeowner's garden.
The rain barrel, rainwater garden and swales follow Low Impact Development (LID) techniques which focus on distributing, storing, slowing, spreading and sinking rainwater into the land on which it falls. It's a take-no-prisoners approach but remember these are the Master Gardeners we're talking about.
The garden has many points to stop and ponder. The orchard is one area I continue to find fascinating – two or three trees in one hole? Wow, could I have my own orchard in my backyard? “Boom-a-rang” berms? What are those? Because the hill creates runoff issues, berms, situated on the downhill side of each planting were fashioned to create a “boom-a-rang” effect on the water. This not only discourages the inevitable erosion, but it acts as a water hoarder for the trees. I finish my walk and am amazed at the imagination and ingenuity it took to convert this challenging site into an advantage.
Today, I had the docents to myself, which was lucky because I had a whole host of questions for them. I'd like to thank the fearless duo, Merril and Frank, who helped me gain a greater insight into what goes on behind the scenes of the Garden of the Seven Sisters. I'd like to encourage all of you out there to visit and I'd love to hear what you find interesting about the garden and if you have questions, we are here to answer!
Before you visit, check out this link if you'd like to bone up on some of the elements of the garden: http://ucanr.edu/sites/mgslo/Demonstration_Garden/
Consider visiting during an Advice to Grow by Workshop. These take place on the third Saturday of every month beginning at 10:00 am.
Calendar of upcoming ATGB workshops:
ATGB Schedule 2014 Jan to June,
ATGB Schedule 2014 July to Dec.
Hear ye, hear ye, this hot off the presses! There will be a plant sale of drought tolerant, Mediterranean plants after the June ATGB.
The Garden Docent Program Has Begun!
Our educational demonstration garden - Garden of the Seven Sisters - will be open to the public every Thursday and every third Saturday of the month from noon to 2:00 p.m. MG docents will be on hand to answer questions about our many educational plots.
Please make note of the following:
- No pets allowed other than service animals
- Rain cancels
- For more information, call or email our helpline - 781-5939, anrmgslo@ucanr.edu
Finally, visit this site if you would like to be notified of upcoming events by email:
- Author: Christie Withers
- Editor: Noni Todd
Cool Weather Veggies and Greens
By Christie Withers Master Gardener
After living in Fairbanks, Alaska for twenty years, I really appreciate the fact that I can grow many vegetables year round back here in California. Some of my favorite varietals for my north county garden add both beauty and food to my raised beds. Kale, swiss chard, spinach and lettuces such as redleaf, romaine, and arugula, thrive throughout winter and spring and will produce before the extreme heat arrives and drives them to bolt.
Many cool weather vegetable varietals will also tolerate a short freeze, which can happen up until early April in the north county. Be sure to read the back of seed packets for temperature tolerance of various seeds. Cool season crops grow best and produce highest quality produce with daytime temperatures ranging from 55-75⁰F. If you are in the south county or along the coastal zone, pick varietals for your particular micro-climate. Garlic, leeks, onions, radishes, peas and potatoes can be planted now and will produce over the next three months. Garlic takes very little room and leeks do well in spring and are relatively inexpensive to buy. Onions are easiest to start if you purchase sets.
Even with the early March rains, water conservation is still a priority. Keep in mind that growing veggies in blocks, using the square-foot gardening methods, will conserve water during our intense summer months. Group vegetables with similar water needs to improve irrigation efficiency. Providing wind breaks and a thick layer of mulch will reduce evaporation and increase the soil's water holding capacity. Be diligent about weeding as the soil warms now so they don't compete with your vegetables for soil moisture.
Do you have questions about what to plant in your garden during the drought?
Visit our educational demonstration garden - Garden of the Seven Sisters - at 2156 Sierra Way, San Luis Obispo. Our garden will be open to the public every Thursday and every third Saturday of the month from 12:00 to 2:00 p.m. UCCE Master Gardener docents will be on hand to answer questions about our many educational plots.
Please make note of the following:
- No pets allowed other than service animals
- Rain or inclement weather cancels
- For more information, call or email our
- helpline - 781-5939, or e-mail us at anrmgslo@ucanr.edu
- Author: Andrea Peck
- Editor: Noni Todd
Replenishing Rainwater Gardens
Groundwater Part 3
By Andrea Peck
If you're not careful, it will sneak up on you. Just simply mosey along any old sidewalk and sooner or later you'll walk past one. It will probably be difficult to spot this clandestine garden feature since it is camouflaged as an ordinary plant bed. But, don't be fooled – you may be looking at the super hero of water harvesting: the rainwater garden. Rainwater gardens may be hidey, but they address a multitude of water sins just by existing.
Rainwater gardens are slight depressions in the garden that are planted with a special blend of drought tolerant and water tolerant flowers or grasses that allow water to pool and soak into the ground. Often native species are well-suited for the job because they tolerate local rainwater vagaries. They also tend to grow long roots that help filter out impurities that accumulate as the water runs into the system. Generally, rainwater gardens are placed in an area that naturally has a water flow towards it. This natural element is then tweaked to pull in more water, allowing it to percolate into the soil. Rainwater gardens intercept the bad boy of the water world: runoff. Runoff can start out as pure as the driven snow, but inevitably turns into a bad apple by collecting pollution as it rolls towards streams, oceans and rivers. Runoff causes general upheaval wherever it runs, often in the form of flooding.
Creating your own rainwater garden is a possibility for the do-it-yourselfer who is willing to do a bit of planning and research. (I'll give an outline here, but for a thorough understanding it is best to research fully before taking on this project.)
You will first need to determine the size of your roof or other impermeable surface that will be feeding into the rainwater garden. A general rule of thumb is to build a rainwater garden that is 10-20% the size of the section of roof or surface that will supply the water. The garden should be built 10 to 15 feet from the foundation of your home. It should not be located near a septic tank, utilities or other structures. Make sure that you select a safe spot – water can wreak damage. Once you find an empty spot that is the right size, you must test your soil for permeability. One way to do this is to dig a hole 1 – 2 feet down and fill it with water. (During dry weather it is suggested that you fill it three times and “measure” the third dousing). Note the water depth and the time. Wait until all the water is drained, note the time again and follow this calculation:
Number of inches of water ÷ the number of hours it took to drain =
Example:
12 inches ÷ 8 hours = 1.5 inches per hour
If your soil drains at .50 inches per hour or better, it is considered well-draining soil.
If you had to bring out the big guns to dig the hole, or if your water is refusing to drain, you may be looking at a spot that has hard-packed soil; you may have to consider another location. Pick another spot and try the drainage test again.
Finding a good spot will be the beginning of your real work. You will have to measure off the area and dig down 8-12 inches. Also, rainwater gardens need an access point, so you will need to build that in. Many gardeners choose to create a rocky swale, reminiscent of a natural dry stream to bring the water from its source (such as the roof downspout) into the rainwater garden. The rainwater garden must also have an overflow in the event of extreme rains.
Before planting, make sure that you have good soil. Generally, you will have to amend the soil, so be prepared to dig a bit more. For well-draining soil, a mixture of 65% native soil and 35% compost is a good mix. For poor soil, 60% screened sand and 40% yard-waste compost is a good combination. Mix the soil well and maintain the 8 to 12- inch depth. Make sure that the basin of the rainwater garden is level. This will prevent pooling in an uneven fashion.
Many plants, including groundcovers, grasses, shrubs, even trees, are appropriate in the rainwater garden. Some examples include: yarrow, manzanita, hair grass, Indian paintbrush, California poppy, sage, manzanita, toyon, coffeeberry and trees, such as California bay laurel, willow and California sycamore.
When planting, leave room for ample growth and finish by mulching. Weed as necessary, water to establish plants and enjoy when rain finally drops.
For more ideas and a video of how to build a rain garden click the link below and enjoy!
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