Selected Questions From the Last Two Weeks

Was given an Ice-cream bean tree (Inga edulis).  Wanted to know how to grow it here.  Has it for 3 years under a huge Ficus tree in a pot.	Advised that it might not survive our winter because it would freeze over at 27F. http://www.tradewindsfruit.com/ice_cream_bean.htm Also asked that if the tree successfully produces fruit to bring it over for ‘inspection’.
Her 40 years old cypress trees are dying.  She lives in Malibu.  She actually sent over some sample leaves to us by mail.	Told her the trees are dying from Cypress canker, a kind of fungi. Once your cypress get the fungus there is little you can do to prevent it from eventually killing the tree. Pruning can extend the life of the tree, but it is vitally important to disinfect your pruning equipment between each cut. One thing that really helps promote the fungus is the number of Italian cypress trees you have in your neighborhood and how close together your cypress trees are planted. Closely planted cypress spread the disease quite readily, and if your neighbors have lots of cypress planted nearby, they can serve as sources of infection for other Italian cypress in the neighborhood. Another reason you have the infection now and not 40 years ago (the fungus was first detected in the 1920’s) is that the range of this fungus has been slowly spreading over time Cypress canker links: Fungus from California suspected of killing cypress trees worldwide | Nature | The Earth Times Gene sleuths trace tree-killing pathogen back to California San Diego Master Gardeners - FAQ - Italian Cypress turn brown Italian Cypress Video – 5min.com CYPRESS CANKER: A Pandemic in Progress - Annual Review of Phytopathology, 36(1):91.
I work on the Master Gardner help line and have a question I do not know how to answer. I would appreciate any help you can give. " I have a Liquid Amber question for Santa Monica. When do the trees defoliate, and for how long? I'm trying to plant a winter vegetable garden and my hope is the sun would shine between the bare branches. In the summer the sun is directly overhead avoiding the tree. "	Hi Rose, Liquidambars here defoliate in late November early December or later (they’re seem to be the last to put on color as well) with re-foliation occurring around March through April. That could be different for Santa Monica because it is not as cold; they could re-foliate sooner.
Our 80-yr-old mission fig tree has splotchy yellow areas on its otherwise dark green leaves. The tree has lots of small green figs on now, but they seem a bit smaller, as do the leaves, from normal. I did some on-line research, and it could be fig leaf rust. How do we tell for sure? Could I send you a couple leaves to I.D.? What's the cure? We have a dog who eats figs - loves them - and will even chew on fallen leaves because they're so good! We don't want to use herbicides that will harm her or us or even the squirrels and other connoisseurs of these figs. Here's some photos of one leaf, front & back, and of others on the tree.  I hope you can tell something by these photos -- it's more obvious in person.   We live in 90064 - in the NW quadrant of the I-10 and 405, west end of Rancho Park Golf Course.	Hi Paula, Your fig looks like it has Fig Mosaic Virus. There is no cure; it’s best to get a resistant variety –Black Mission is the most susceptible to this virus which is transmitted by mites or by rootstock. Spraying may work for rust, but not for viruses. However you can prevent the spread of the virus to other Fig trees by spraying for mites on a regular basis. UC Davis page on Fig Mosaic Virus: http://www.ipm.ucdavis.edu/PMG/r261100611.html

Peach Tree is Dropping the Ball

Q. Can you help me resolve a problem that has developed with my two peach trees? They are now giving reasonably good quantity and good size fruit, but the problem that has developed is that the fruit drops before it is ripe. Is there anything that can be done to help the tree hold on to the fruit until maturity?

A. Peach trees regularly thin themselves out before ripening occurs; if this didn't happen the peach’s branches would break under the weight of the ripening fruit. In fact, when the peach starts to show signs of fruit dropping (it's starting to self thin) it isn't a bad idea to water the tree heavily and then, the next day, shake the main trunk gently but rapidly to thin out the juvenile peaches before they get too big and pose a risk of collapsing the branches that bear them.

A London Planetree in Pain?

London Planetree leaf (Platanus x acerifolia) showing symptoms of Mildew infestation.

I found this sitting on my desk with a note wondering what was wrong with the tree. No identification but the soft maple like leaves coupled with the the problem itself ruled out anything but the leaf being from a London Planetree (California sycamore leaves are similar but usually much larger). The problem is a fungus known as mildew. London Planetrees are susceptible to mildew, and the recent long period of cool weather has increased the amount of mildew I'm seeing on everything. Mildew is what is known as an obligate parasite, in other words it needs its host to survive so it will not kill it...but -it can make the tree look pretty bad, especially if its a variety that is not resistant to mildew. If the tree were in the wild this would not be a big deal, but here the life and death of trees is dependant on how we like them as ornamentals and a tree that is constantly coated with leaf curling fuzzy-white mildew could irk someone enough to consider removing it; thus curtailing its changes of surviving.

So what can be done to alleviate this blotchy leaf-deforming parasite? The best thing to do is wait -time will heal this as long as we have a summer that is somewhat close to normal. Hot temperatures and dry weather will desiccate the mildews branching, threadlike vegetative state and cause its existence to be less noticeable by us human beings who don't appreciate its leaf distorting fuzzy presence.
What about fungicides? Applying fungicides to large trees is, unfortunately, inherently expensive and dangerous. A spray service could do this for you but you'd be literally spritzing your money away.

There are varieties of London Planetree that are more resistant to mildew and another leaf disfiguring fungus called anthracnose; these include 'Bloodgood', 'Liberty' and 'Columbia' but unless the extended June gloom that we've been having that caused this problem in the first place becomes a permanent climate feature here I would just keep the tree you have and wait out the fuzzy invader. Also, remember to keep the old leaves picked up off of the ground -they could be the source of other fungal problems if you allow them to rot on bare ground. Many leaf attacking fungi are spread when infected leaves touch the bare ground and stimulate the production of fruiting bodies (the term for the mushroom like structures that grow off of the leaf that would be roughly analogous to a plants flower).

July Plant Information Class Will Be on the 11th at 1:30

Hey everybody just a reminder,  my plant information class held usually on the first Wednesday of the month,  will be held this month on the second Tuesday, July 11th at the usual time; 1:30 pm. This class is going to cover cactus and succulents. We're going to look at the major types of cactus and succulents (selected families and genus) and talk a little bit about strategies for developing a cactus and succulent garden like the ones you see at the Arboretum and the Huntington.  As always we're going to look at some of the most interesting, entertaining, and even strange plant information questions that the plant information volunteers and myself have fielded over the last month. I'm also going to be talking about a new pest, the 'shot hole borer'. This is an interesting pest that has already killed and damaged trees here in the San Gabriel valley.  you don't want to miss this meeting. Lastly,  it's hot, so were going to be, as usual, in the well air-conditioned plant information headquarters located in the library building here at the Arboretum. See you there!

One Messed Up Mulberry

A gentleman brought in a Mulberry (Morus alba) shoot from a tree that was having problems. The new foliage was distorted and seemed to wilt over the course of one to two months. According to him the onset was sudden and no other nearby trees (this was the only mulberry) seemed to have the problem. We ruled out a gas leak and upon viewing the shoot under magnification no insects or insect debris were noted.

Distorted Mulberry Shoot

After ruling out insects and diseases the last thing left was to investigate physiological (nutrition, salt burn, etc.) causes and finally, herbicides. Going through the list the only description I found that matched the damage to the shoot was that for 'phenoxy' herbicides (the giveaway was the curly-queue stems). One of the most common scenarios where this type of herbicide damages trees and shrubs is when 'weed and feed' lawn fertilizer is applied to the lawn under the canopy of a sensitive tree. The owner of the damaged tree however did not apply any of this kind of fertilizer on the lawn under the tree. Another cause of this kind of damage is a disgruntled neighbor spaying an herbicide intentionally on the tree, but the tree owner denied having any tiffs or feuds with fellow neighbors. 

So the most likely cause of this damage to his tree was a neighbors spraying accident. 'Phenoxy' type herbicides (those containing 2-4 D and similar compounds) are notorious for causing damage to trees from spray drift caused by applicator error or applying the spray in windy, hot conditions. All it would take would be a neighbor spritzing weeds in his lawn with a hose end, pump, or hand pump sprayer in a light breeze; and to top it off Mulberries are notoriously sensitive to these types of herbicides. 

The treatment? If the accidental dose is not to great the tree should grow out of the damage either before the summer or next spring when the tree re-leafs after its winter dormant period.

This Wednesdays Plant Information Class -Tree Donor Tour - Plumeria Question

This Wednesday's Plant Information Class

This Wednesday, June the 6th Plant Information Class will be held in my office at 1:30. The topic will be about plant allergies and how to design a landscapes for those of us who dread spring for the pollen firing squad it is. I will also be introducing all plant information volunteers in attendance to an exciting new project that should get us all published.

Tree Donor Tour

I was honored to be a co-presenter on today's Tree Donor tour. We had about 50 people take the tour which gave an overview of the horrendous damage that occured as a result of the December 1st windstorm. In all we lost over 245 trees and 26 days of operation due to the storm. Arboretum Director Richard Schulhof, Superintendent Tim Phillips, Senior Biologist Jim Henrich, and myself hosted the 90 minute tour which also covered some of the new collections we'll be initiating as a result of the wave of donations recieved and the art exhibit curated by Leigh Adams that uses wood from the felled trees as the material for art created just for  the exhibit.  Here's a video: http://youtu.be/Ck868XcqW1I 

The Damage

The tour covered the vast magnitude of the damage to the Arboretum and why some trees failed and others didn't. One of my favorites (in terms of examples of preventable tree failure) is the 150+ year Blue gum that failed as the result of the damage the tree suffered when a metal conduit was installed next to it in the 1960's. Other interesting tidbits were the decapitation of palm trees by the flailing limbs of the huge cypress trees next to them and the inability of large, tropical ficus to stand up to the wind.  

The Recovery

Right after the windstorm large areas of the Arboretum were inaccessible to vehicles, so the first thing that had to be done was road clearance. County fire crews and other county crews were invaluable for this. Brush clearance crews from parks, public works, agricultural commissioner's office and other county department personal came to our aid immediately after the storm. Call me a sentimentalist but it really struck my heart how these crews all seemed motivated by a feeling of admiration for the Arboretum. These guys were really motivated to get the Arboretum open again so that people could enjoy this place. Now all this enthusiasm and sentiment was great, but  the real stars, in my opinion, were Tim Phillips and Jim Henrich who both were able to steer the extremely enthusiastic crews in the right direction and ensure that the more sensitive parts of the L.A. Arboretum's collections were not compromised by that enthusiasm. 

One of the strategies Tim put in place that really helped keep the clean up from being more damaging than the windstorm was to make sure only Arboretum crews worked in sensitive areas. This included most of the road-inaccessible parts of the collection and the Tropical Forest area. 

Another incredible and heartening result of the disaster was the outpouring of support from the Arboretum from the public. We had hundreds of phone calls, emails and inquiries wondering what that individual could do for the Arboretum. That's when we started the tree fund; since then the fund has accumulated over $70,000 in donations. 

New Collections Started, Old Collections Renewed

Besides the tree fund one positive result of the storm has been an invigoration of our collections programs on several fronts.

Seed Acquisitions  

Jim Henrich has been acquiring seeds from index seminum (seed index)  lists from various botanic gardens around the world with concentrated focus on:

• Australian Plants
• Will probably focus on trees and shrubs that are less messy, less fire-prone, and flower more than previous Arboretum acquisitions as well as flowering perennials, both herbaceous and bulbs. 
• South African Plants
• The Southern California-like climate of the South of Africa and the Cape of Good Hope area will continue to be a source of acquisition for non-invasive specimens for our collection. 
• South American Plants
• With special emphasis on Chilean, Argentinian, Brazilian and Peruvian plants from climate zones similar to ours. One tree in particular that we hope to increase our collection of; the genus Tabebuia a south and central American flowering tree that has quite spectacular blooms and shows great potential as street tree here in L.A. County. 

Engelmann Oak Grove

The Arboretum's Engelmann oak grove is the northernmost pure stand of a remnant oak population that spanned an area from northern Mexico up into Arizona and over to the coast of southern California. In that the stand is unique and that part of the trees range has been shrinking due to development it is an ecological treasure. Jim Henrich has started a program that will help to ensure that this treasure is available for generations to come. Ever the Arboretum was started in 1948 very few oak seedlings have established in the Grove located on the south side of Talac Knoll. This is because the fires necessary for oak establishment, and the dominance of invasive non-native grasses, coupled with the use of string trimmers by contract maintenance crews, have combined along with a large population of seed and seedling eating ground squirrels to keep establishment of Engelmann oak seedlings to a next to nothing level. In the last two years Jim Henrich's oak establishment program has lead to an increase in survival in these seedlings which you can see if you go up to the grove on the Knoll and observe the number of chicken wire encased seedlings that are now growing there. For more information pick up a copy of the 2012 early spring edition of Pacific Horticulture in which Jim details the Arboretum's oak conservation efforts. 

Erythrina Collection

One of the hardest hit trees in the Arboretum were the coral trees, genus Erythrina. As a result it is one of the collections that will be greatly expanded here. In 1966 the city of Los Angeles made Erythrina the official city tree but did not specify a species because it was thought that between the many species of the genus that there would be a greater flexibility in cultural conditions for the many micro-climates of Los Angeles.  Already we have planted E. corraloides  in the spot where several E. crista-galli were first burned from the bad frost of two years back and then decimated by the windstorm. On Tallac knoll where frost is not much of a problem new plantings of Erythrinas including E. speciosa have been installed. 

Art from Disaster

Leigh Adams is curating an exhibit scheduled mark the anniversery of the windstorm. Over 70 artists have selected wood from storm-felled Arboretum trees and tree limbs to fashion into artworks that they will later donate back to the Arboretum for the exhibit and to raise funds through the artworks sale. 

Plumerias from Cuttings

Q. My friend wants to plant Plumerias from cuttings now by cutting them and placing them in water; can she?

A. Although now isn’t a bad time to take Plumeria cuttings, it’s just not the best; the best time is when they are just starting to leaf out in the spring. If you decide to root them now they should be about 8-12 inches in length. Make a clean cut with a sharp knife and disinfect the knife between cuts (very important) the best way is to dip the knife in grain alcohol and flame it with a propane torch until all the alcohol burns off. The second best way is to use a 10% Chlorox solution (hard on the knife; make sure you wash and DW-40 the knife before you put it away). After you make the cuttings take off all of the leaves and flower buds and store them in a cool dry place for at least two weeks to allow the cut end of the stem to heal over. This is very important if you don’t want to see your Plumeria cuttings deflate like punctured balloons after they are planted. After they are healed dip the bottom of the cutting in water and then rooting powder before planting it about 3-4 inches deep in the potting soil in 1 gallon containers (this should be cactus mix; there is also a method of using pea gravel to stabilize the cuttings shown on the first link below. Put your potted Plumerias in at least half day sun (they need heat to root). Water your Plumeria cutting only once until you see new growth, then water regularly. Check out the video, as the author talks about using dark rocks as a mulch to warm up the soil to encourage rooting.  

However, if your friend insists on placing freshly cut Plumeria shoots in water she runs a good chance of brewing a batch of rotten Plumeria tea. 

This site talks about planting the cuttings.

http://www.plumeria101.com/cuttings101.html

This video talks about the healing process and demonstrates how to root the cuttings. Also talks about using dark rock mulch and when to water the cuttings. Very good video:

http://youtu.be/PEDiy5m-3ng

Beetle-fungus disease threatens crops and landscape trees in Southern California

Beetle-fungus disease threatens crops and landscape trees in Southern California

Color In The Garden

The use of color in the garden is a powerful tool -when used correctly. Here are some links to sites and articles that discuss landscape color: 


Using color to set the mood in landscaping
http://www.landscapingnetwork.com/landscape-design/color-wheel.pdf


Video about using a color wheel -gives you a little bit of an understanding about how colors are percieved.
http://www.5min.com/Video/How-to-Understand-And-Use-The-Art-Color-Wheel-103069948



The Impact of Color on Learning
This article highlights research on colors effect on learning and psychology in a school setting
http://www.coe.uga.edu/sdpl/HTML/W305.pdf



Virtual color wheel that you can use on your Android tablet. Just match the color of the flowers you are considering using with this application and jot down the RGB code for that color. Later on you can use Photoshop or paint and 'paint in' the color scheme over a photograph of your garden using the codes. 
http://www.colorspire.com/rgb-color-wheel/

Another interactive color wheel.
http://thevirtualinstructor.com/interactivecolorwheel.html


Proven Winners: Select from the 100's of 'Proven Winner' color annuals, biennials and perennials by color:
http://www.provenwinners.com/images?keys=blue&photo_type=Close-up&field_introduction_year_value=&plant_program=All

Rose Show Today and Tomorrow Here at the L.A. Arboretum and Botanic Garden

Pacific Rose Society judges (l. to r.) Dwyn Robbie, Ron Feurer and Diana Kilmer discuss entrants at the April 28th, 2012 Rose Show here at the L.A. County Arboretum & Botanic Garden

Fresh-cut roses awaiting judging. 

Rose shows are fiercely competitive. Amateur rose growers take special care and patience to ensure that their entries will outshine others. However, even if you are inexperienced in the world of roses, you still have a chance to win. There is usually a novice category that is a little forgiven if you don’t yet know all the tricks and ropes. Here is a very good article that summarizes what the judges are looking for, and some pointers for winning by Robert B. Martin, Jr. from the Santa Clarita Valley Rose Society: How Roses Are Judged. The Los Angeles County Arboretum and Botanical Garden is hosting the annual Rose Show this weekend, Saturday April 28 through Sunday April 29. Stop by, enjoy and smell the roses. May be you will find some inspiration and enter in next year’s rose show!

Arboretum Rose Show and Sale Page: http://www.arboretum.org/index.php/events-and-classes/details/rose_show_and_sale/?start_time=1335643200&end_time=

Pacific Rose Society Annual Show Page: http://www.pacificrosesociety.org/roseshow.html

Rose Competition Links:


How Rose Shows are Judged
http://scvrs.homestead.com/HowRosesJudged.html
This is a very good article that summarizes how rose shows are judged,
and what things rose growers who enter the competition should watch
out for.

Putting Your Best Petal Forward (pt 2): Grooming Roses for Rose Shows
http://mymontys.com/wordpress/?tag=rose-competition

Rose show is fragrant with fierce competition
http://www2.journalnow.com/lifestyles/hg-garden/2008/jun/07/rose-show-fragrant-fierce-competition-ar-107359/

Things You Need In The Garden……. To Win
By: Richard Anthony & Kristine Vance
http://www.westernreserverosesociety.org/Informational%20articles/Are%20You%20Ready%20To%20Exhibit%20-%20Things%20You%20Need%20In%20The%20Garden.pdf

TAKE YOUR BEST ROSES TO THE ROSE SHOW
AND DO YOUR BEST
http://www.pacificrosesociety.org/TakeBestRoses.ht

Dr. Dodds' Presentation on Yellow Dragon (Huanglongbing) Disease to the San Diego Rare Fruit Growers

UCR Professor Allan Dodds made the following presentation to the San Diego Rare Fruit Growers.

Plant Pathology Books and Links

Books:

Plant pathology [by] George N. Agrios. Drawings by Mareile Fenner.New York, Academic Press [1969]

Links:

UC Davis IPM Home and Garden Pages

Plant Disease Symptom Chart

Tomato Plant Illustration With Disease Symptoms

Colorado State Garden Notes (with pix of disease symptoms)

Tomato Disease Symptom Diagnostic Chart

Nattrassia Canker on Ficus

Vanilla Orchids in Tropical Greenhouse Pollinated.

Tongan vanilla rancher Hema Alatini demonstrates how to pollinate orchids. He came in this morning during the 1 hour window of time in which the orchid blooms can be pollinated.

An Underground Cistern for Water Harvesting at the Arboretum

When you come to GROW! a Garden Festival here the first weekend of May you will be there for the grand opening of the re-designed Garden for All Seasons. Needless to say the contractors who are installing the garden are really putting the jets on in order to get ready for the only three and some fraction weeks away grand opening. Below are pictures I took the installation of the underground reservoir for the water harvesting system. Hopefully they'll be some rain for it harvest (but really hopefully not during the weekend of 'GROW!'). This is some really cool tech here, let me explain.

This is the hole that was dug for the cistern. It's about 6 feet deep.

Here you can see the crew from Exquisite Ponds & Gardens lining the hole with PVC to waterproof the sides and bottom of the cistern.

Here you see they have placed a bunch of plastic milk-carton like structural elements. These cage-like boxes make the cistern incredibly strong and resistant to collapse. I'll show you some more progress soon! Stay tuned.

Plant Information Class: Field Trip to California Cactus Center

Several of the Arboretum's plant information volunteers and myself went to California Cactus Center in Pasadena for a tour. For those of you who missed it enjoy these videos I shot of the tour.

Citrus 'Worst' Disease Detected in Hacienda Heights: Can Spinach Come to the Rescue?

Huanglongbing (HLB) early symptoms on citrus leaves. 

Huanglongbing (HLB) disease of citrus, also known as citrus greening disease, has been detected in citrus pysllids and plant material the local neighborhood of Hacienda Heights. HLB is a devastating disease that leads to the death of infected trees and can lead to the destruction of the California citrus industry (it's already destroyed over 40% of the citrus trees in Florida). It looks grim but there may be a glimmer of hope represented by a gene found in spinach by Texas A&M researchers that helps fight off the disease. Unfortunately field testing has just begun on trees modified with this gene, so it may not be available for 10-20 years. Since the disease spreads rapidly (infection in the Florida trees was only first detected in 2005) that might not be enough time to save a good portion of the industry here. However, like many plant diseases it remains to be seen if the climate difference between the humid, topical climate of Florida's citrus areas and the hot, dry climate of California's citrus areas will have any effect on the spread and severity of the disease.

Associated Press Article on HLB Discovery in California and Texas A&M Spinach HLP Resistance Gene Modification

Huanglongbing (HLB) symptoms on citrus.

California Department of Food and Agriculture HLB Press Release

What Do Oaks and the Irish Have in Common?

 This is a Quercus agrifolia, commonly known as a coast live oak, that was brought to my attention by a North San Gabriel Valley resident. The branches of the tree had defoliated over the last several years. The lawn is a year old, but the previous owner had grown ferns under the tree before that.

This tree is a great example of an oak that might be saved. Live oaks are notorious for defoliating under stress. You might wonder, considering the verdant and luxurious lawn that can be found under this tree, what the source of this defoliating stress is? Well consider the verdant and luxurious lawn for one...and the ferns the previous owner grew underneath the oak. Both of these require lots of water compete with the tree for nutrients. But simple competition isn't the only thing. Oomycetes (in particular Phytophtora species ) organisms that are commonly called water molds, are mostly to blame. Related to the organism that caused the Irish potato famine in the mid 19th century, these destructive organisms grow, multiply and thrive in watery environments. A well irrigated lawn is one such watery environment. The film of water that coats the soil particles in moist lawns is enough to allow the swimming spores of oomycetes to infect the roots the oak tree and cause considerable damage -as well as providing a gateway to a more destructive organism; oak root fungus. It's also a good idea to check the drainage of the area around your oak to make sure that any recent construction hasn't created an impairment for the runoff of water from the area.

So what can be done? The first thing is to tear out the lawn underneath the canopy (or the area that would have been the canopy if the tree wasn't defoliated) and mulch the area with shredded bark. Then allow the trees own leaves to build up in a thick layer underneath the tree. If recent construction has impaired water runof, fix it so that water drains away from the area where the oak is planted. Then treat the area with Agrifos according to instructions (Agrifos is a type of fertilizer that has a preventative action against oomycetes). And finally adjust your watering so that you are not watering the tree; natural rainfall is usually enough to sustain the tree. However, additional watering may be necessary in situations where it is a drought year and the original water gathering root area of the tree (which can be an area up to twice the diameter of the tree's healthy canopy) is compromised.

Here is a particulalry good publication that goes over what can go wrong with oak trees.

Carried Away

 It's hard not to get that here when it comes to photography.

Is This An Oak Defoliation Culprit?



Chaperral camel cricket; responsible for a naked oak tree?

  I received a picture of this guy in my email a week back from a local oak tree owner who was finding them on her now defoliated oak tree. Was this one of the infamous 'Gold Spotted Borers' whose occurrence here could spell doom for thousands of our Oak trees? Well, probably not as evidenced by this creatures large hind legs; do they look familiar? Yes, it does look like a cricket and, according to L.A. County Agricultural Commissioner's office entomologist Gavork Arakelian this is a native cricket known as the 'Southern California chaparral camel cricket'. It does eat leaves, but whether it's responsible for defoliating an entire oak tree is questionable. There are other insects that can cause defoliation including the California Oakworm, but many of those are summer pests and are inactive in the spring. Still, a closely related insect in Texas has been known to defoliate oak trees. So is this the culprit? Although I don't have enough information it is possible but not likely  because the Chaparral cricket is omnivorous, it will eat anything,  including oak leaves.

Pad Tours



Holding tablet with picture of work-in-progress at the Madagascar spiny forest exhibit showing; can this work on a sunny day also?

  I just tested an Andriod tablet as an interpretive device today and I was pleasantly surprised. I was giving a tour to a group of about 14 college students and I used the tablet to show pictures from a powerpoint presentation on the history of the Arboretum that I had uploaded to Google web albums (AKA Picasa web albums). The students were able to see the pictures, and navigating through the album was breeze. Now today was quite cloudy so there was no problem with glare -I am looking forward to trying this out on a sunny day and see if slighlty tilting the screen down and away from the viewers will eliminate the glare (should work unless the ground is snow white).

I Get Critters To Identify

 A client brought in this one two days ago. Several of these were found in a bathroom on the floor. At first I thought they were maggots and I wasted a lot of time searching for them, but I did learn a lot about maggots. Then I axed the maggot approach and I finally came up with what they were; case bearing moths (Tinea pellionella). Here's a video of them showing how the larvae extend out of there protective case and drag it along.

The 'cases' are shells of silk they weave for themselves that are sticky; that's why you see all the dust and dirt adhering to them. They eat wool, feathers, fur, hair, upholstered furniture, leather, fish meals, milk powders, lint, dust or paper. There is no shortage of things for them to eat in a bathroom.

Controlling them is a matter of hygiene and environment. They like to hide out and feed on dust and fibers, so keeping baseboards (where these two were found) and other hard to reach areas adjacent the floor clean is important. It also very important to dry clean your clothes if you are going to hang them up for a couple of days. The moths are attracted to dirty wool and fabric. Keeping your house relatively dry also keeps them away. UC Davis's IPM sight has more information here.

A Field Trip for Plant Information Volunteers.

X Chiranthofremontia lenzii, a cross between the Monkey hand flower  and Fremontodendron sp. 

Ten people, including seven plant information volunteers and their spouses, joined me for a field trip to the Ranch Santa Ana Botanic Garden yesterday. It was a gorgeous day and everybody found interesting plants that they'd never heard of before (including me). Here's a link to photos of some of the plants we saw.  We were lucky enough to have Patrick Larkin, the garden's director, speak to us before we began our tour. We were also privileged to have grounds director Joan McGuire (who worked here at the Arboretum as the herb garden curator before accepting her position at RSABG) and tour coordinator Judy Hayami (also ex of the Arboretum) meet us before the tour began.

Field Trip To Ranch Santa Ana Botanic Gardens Wednesday March 7th @ 2pm

I hold monthly classes for all my plant information volunteers on the first Wednesday of the month at 1:30 pm. The classes are usually held in my office, are free, and are also open to members of the general public for free. I give slide presentations (last month we looked at tree damage here at the Arboretum) and go over the most interesting questions I recieve during the the last month. This month we're doing something different.

Between 1:30 and 2pm this next Wednesday (March 7th) we'll all be meeting at the entrance kiosk of the Ranch Santa Ana Botanic Garden (RSABG) in Claremont. Remember you'll be responsible for your own transportation to RSABG, and you'll also be responsible for your admisson (free if you're an Arboretum member -don't forget your card).


View Rancho Santa Ana Botanic Garden in a larger map


Admission:
$8 Adults
$6 Seniors (65+)
$6 Students w/ valid ID
$4 children aged 3-12
No charge for children under 3

If You Are An Arboretum Member You Will Receive a Free Reciprocal Admission, Don't Forget to Bring Your Arboretum Membership Card. 

How To Get Great Shots of the Arboretum

How to Process Great Shots of the Arboretum using HDR (High Dynamic Range) Software

One of the big problems photographing any outdoor scene is the huge amount of contrast you might encounter. If you expose the picture at a high ISO you get more details but your color seems washed out, expose at a low ISO and you get vast amounts of shadow that take away from the image. Now there is software that can take 'bracketed' (two or three pictures taken of the same scene; one at the recommended exposure and the other one or two a step above and/or below that value respectively) The software evens out the tones and keeps the contrast from being too high. It can also compress the tones to make them more colorful and dynamic, but not to the point where believability has to be suspended. Below is an example two photographs I used HDR on to make a single, dynamic and impactful image. 

Shot of aloe section and cactus and succulent section at recommended exposure level (Nikon D5000)

Shot of aloe section and cactus and succulent section at  1 step under recommended  exposure level. 

Composite of above images created  using HDR software. 

Right now I'm using Photomatix Pro for my HDR processing, it's about$90 and you can download a trial version (it leaves a watermark on the image when your done). 

• Stuck In Customs travel photography blog section on HDR photography. 
• Luminence open source HRD software. I haven't tried this but it's free -let men know how it works for you. 

But Wait!!!

If you're a fan of cheesy infomercials and large potentially invasive vines that attract hummingbirds and can give you a rash (albeit a fast disappearing one), then this is for you: https://www.hummingbirdvinesoffer.com/

BTW, the vine is Campsis radicans, a member of the Bignoneaceae family (the same family that brought you the Pink trumpet tree, Tabebuia impetiginosa).

Tabebuia's In Bloom Now

You know spring is really here when the Tabebuias start blooming. Native to South America, they do very well here as moderate growing shade trees up to 50-60 feet tall. . Most of our specimens made it through the wind, although one very early blooming tree was severely damaged. We're keeping the tree, but it's not pretty. All that's left is a stump but hopefully that will grow back sufficiently to provide us material enough to make some cuttings. Before the wind snapped it in half you could see it blooming, always several weeks before all the other Tabebuias, behind the wedding gazebo located at the north end of the event lawn. Still the view from the lawn is spectacular, and a smaller Tabebuia located next to the carnivorous plants greenhouse has taken up the slack.

Foot Wide Magnolia Blooms in the Herb Garden

*Magnolia x   veitchii? in bloom in the Herb Garden

Magnolia x veitchii?  being admired by staff. (l to r) Arboretum herb garden curator Theresa Rachau and Irene Chang.

 Located in the herb garden, this large flowering Magnolia is blooming right now. The monster flowers can be up to a foot across, and they have an odor much like peppermint. The identity of this beauty is a little bit of a puzzle, as it was accessioned . It has  some characteristics of Magnolia campbellii (the large bloom and pleasant odor) but was accessioned as Magnolia x veitchii, a cross made by British horticulturalist Peter Veitch between M. campbellii and M. denudata in 1907.

* At first I thought this was Magnolia campbellii var. albe 'Stybing White'; but it turns out that this Magnolia was accessioned before M. campbellii var. alba 'Strybing White''s introduction in 1962. 

Browse Our Magnolia Collection -Beta Testers Wanted

I've published a Google map of our Magnolia collection. Each one of the blue icons is a Magnolia in our collection, just click on it and you'll get a short description and history of each plant. It's cool, but the coolest thing is that you can load this map up on your Google Maps app on you iPhone or your Android phone and use your GPS to find out what Magnolia you're looking at in the field. Try it out if you have one of the above and let me know how it works for you.

View Flowering Magnolias at the L. A. Arboretum in a larger map

Wild and Wooly

When I started this job 14 years ago I'd get lots of stuff in the mail. Sometimes the packages would be dripping strange fluids, emitting strange odors and containing strange life forms. These days with email and digital photography I'm mostly spared these surprises but there are still things that require a sample. The pest below is a good example of this. What you see is a citrus whitefly. Now 'citrus whitefly' is a term for any of three different species of whitefly that currently infest citrus trees.

Sample of citrus leaves with wooly whitefly infestation. 

The sample you see on the left is a lemon tree that has been infested with citrus whitefly. Notice the fuzzy white patches. These patches are the reason I needed to see this sample. When this had been originally described to me it was described as a 'fungus'.

Now of the three whiteflies that infest citrus here this one appears to be the 'wooly whitefly'.

Now if you look closer (the lower two images were taken with a magnifier) you'll notice that the 'fungus' looks more like cotton and that there are what look like scale insects surrounding the fuzzy stuff. These 'scales' are actually the immature (nymphal) stages of the whitefly. These 'nymphs' will eventually cover themselves in a cottony tuft of wax fibers (the 'wool' in the pests common name)  that the exude from their bodies. This wax serves to protect them from predators and it also repels water (that's why most contact insecticides will not control them very well).

Some methods of control that do work are:
1. Pruning the tree to increase air circulation.
2. Spraying horticultural oil solution on the tree. This has to be done during the cool time of year or else the oil spray will damage or kill the citrus tree's foliage.
3. Decreasing the amount of nitrogen that the tree receives. Instead of feeding three times a year feed just once.  If you feed citrus too frequently their sap's concentration of nitrogen goes up. Since nitrogen is the limiting factor in the growth of the pests (they've got all  the sugar they need for energy -what they need is nitrogen to form the proteins of their body tissues) if you over fertilize you're practically sending out an invitation to white flies and pests like them to infest your trees. Use organic fertilizers because their availability coincides with the availability of the natural predators that keep the white fly under control -in other words when its warm outside there are lots of predators to control the whiteflies so that is the ideal time you want fertilizer to be available to your citrus trees.  Do not use fertilizers that are immediately available to the plant like ammonium nitrate and urea (found in commonly available water soluble  fertilizers like 'Miracle-Gro').

For more information on control of this whitefly download this PDF:

January 17th out in the Arboretum

Flowering stalks of the King palm (Archontophoenix cunninghamiana).

Tan, pom-pom like flowers of Acacia stenophylla blooming in the Australian section.

Acacia spectabilis, the 'Glory Wattle', earns its common name. Located in the Australian section.

Acacia merinthophora's distinct arangement of stems and phyllodes (leaf-like stems) gives it its common name: the Zig zag wattle.

Back from Flu Bout; Class Rescheduled

I'm back after a wicked bout with that seemed like the flu. For all of you who missed the class yesterday I'll be holding it next Wednesday, same time same channel (1:30 to 3:00 in my office). I'll be covering Spring bulbs, local fungus (in preparation for the rainy season which is not here just yet), and of course the best of 2012's plant information questions so far.

Here's a cool link; it's the UCR Avocado variety page. The trick is to select at least two varieties that are good for your climate zone and are A and B type Avocados respectively. Having both of these flowering types can help insure a steady and abundant supply of Avocados.

A Rant On Liquidambars

 Our recent breezy weather is bringing out lots of concern about the safety of trees planted next to houses. I recently had an inquiry regarding one tree that should never be planted near houses or any hard-scaping for that matter...and it's not a Ficus.

Liquidambar styraciflua is a tree native to parts of the Southeast United States, Mexico and parts of Central America. It’s called a ‘Sweet Gum’ because Native Americans would chew the tree’s resin like chewing gum.  The tree is not at home here in dry Southern California. Where it's native the precipitation averages 25-35 inches of rain a year. The problem is that it is also a tree that has evolved to survive in rocky, infertile soil in its native range.  This ability to ‘tough out’ those harsh conditions makes it appear to be the perfect tree for Southern California; nothing is further from the truth. With the dry winds and the infrequent precipitation Liquidambars here are constantly under water stress.  They also have the propensity to develop very invasive and destructive roots.  But wait there’s more. Ever since 1998 when a new pest called the ‘glassy winged sharpshooter’ was introduced to California Liquidambars have been infected with a disease called ‘scorch’.  First appearing on Oleanders, this disease is a bacteria that plugs up the water conducting tissues of the plants it infects and causes the shoots furthest from roots to dry out so fast they literally ‘scorch’ where they stand.  This has gotten so bad in parts of Riverside county that it causes the trees to die back to almost 2/3 of their former height, causing them to look disfigured and leading to their removal for aesthetic reasons.

Now also consider that the  chances of damage from the wind toppling Liquidambar  trees is  probably not as great as the chances that the trees roots will damage some structure that the tree is within 10-25 feet of. 

So all this leads me to my final opinion on yours, and every other Liquidambar tree growing in Southern California. Unless your tree is at least 25 feet away from any structure it can damage with its invasive roots, and is surrounded by a lawn (which is the only way it’s going to get sufficient water to remain healthy and tolerate the effects of the scorch disease) I would remove the trees and plant something else.

Links:

Here's an article I wrote two years ago about Liquidambars

Australian Garden Expert Don Burke's List of Trees to Avoid; This Advice Good for Southern California Too

Scorch damage on a Liquidambar leaf