Saturday, May 25, 2013

Mildew's and Don'ts

June gloom is here; always a welcome respite from the erratic heat waves of May but a month that can be a problem for plants susceptible to the mildew fungus. I’ve composed the following do’s and don’ts to help your garden remain as free as mildew as possible.


Do select and grow mildew resistant plants. Roses, Crepe Myrtles and other plants that are notorious for harboring mildew usually have varieties that have been selected to resist the powdery white scourge.


Don’t fertilize. Nitrogen based fertilizers increase susceptibility to mildew
Do use copper dormant spray on deciduous plants. These sprays will help kill mildew when it germinates in spring.


Do wash the plants foliage; mildew spores cannot germinate on the ground, so wash them off during mildew season, however do not use this method if you have other fungi infesting your plants (like rust) that are spread by water.


Don’t allow weeds and un-composted leaf litter to collect around susceptible plants (this is good advice for all plants).


Do use simple, organic methods of control (see below).


Don’t let mildew get you down; it’s an obligate parasite which means it needs its host alive to survive. At worst it will stunt your plant but it almost never kills plants.




Paper on stomatal density and powdery mildew infestation: http://www.ncbi.nlm.nih.gov/pubmed/22476473



Organic Mildew Treatments
The Cornell Baking Soda Formula and other controls: http://www.organicrosecare.org/articles/recipe_mildew_control.php

Milk Spray: 9 parts water to one part milk; probably works by clogging stomata so that the fungus can't enter the plant. It's reported that skim milk works best.
Neem oil can have a preventative effect on mildew, but I've had too many reports of plants burning from its use to recommend it.


Wednesday, May 22, 2013

Canary Island Color Here at the Arboretum


Limonium, commonly known as statice or sea lavender, is in bloom now in the Arboretum’s Canary Island collection.  This plant, a member of the Plumbaginaceae family, originates from the Canary Islands, a Spanish archipelago off the northwest coast of Africa better known for the sun and sand of Tenerife and the Gran Canarias than for its unique endemic flora. These islands form one of Spain’s autonomous communities and enjoy a subtropical climate with long, warm summers and moderately warm winters.  


Right now you can see large flowering specimens of tree limonium (Limonium arborescens), a tough perennial herb grown from a woody rhizome, a modified subterranean stem usually found underground which often sends out roots and shoots from its nodes.  The flowers are unusual in that they have lavender sepals, the outermost whorl of parts that form a flower.  In most other plants, sepals are usually green and typically protect the flower in bud and often support the petals when in bloom. Its these sepals that make the Limonium inflorescence so spectacular.

Limonium arborescens (foreground) blooming in the Canary Island exhibit. 



A similar looking and commonly available Limonium is Limonium perezii, known as Perez’s sea lavender; also a Canary Island native.  L. perezii blooms nearly year round but heaviest in summer.  The foliage grows to about 18” on a 2 foot clump, with flower stalks about 2-3 feet tall.  The calyx, the outer papery envelope, is rich purple; the corolla, the inner part, is white.  The plant is drought tolerant and, once established, needs only occasional watering.  It grows best in dry, well-drained locations.  Clumps should be divided every 2-3 years in early spring.

Less widely available are Limonium found in other colors.  L. platyphyllum, native to central and southeastern Europe, has a white calyx with bluish corolla.  Even pure whites and pinks exist.  L. sinuatum, a Mediterranean native, comes in even more colors:  yellow, apricot, orange, peach, and rose in addition to the usual blue and lavender.

Most Limonium do well as cut flowers and their papery nature makes them prized for use as dried flowers.  They keep their color well whether cut or in the garden.


Wednesday, May 8, 2013

Plant Identification Links


Links for Plant ID Class

List of conifers and hardwood trees native to North America.
Full on University of Wisconsin course on plant identification and classification.
Very browsable list orders, families, genus and species with example photographs. Also includes usefull family key.
Gives you an idea of when plants evolved and what they are related to.
You can go through to genus starting from the kingdom Plantae.
Read the history of European plant classification.
Review terms you already know and learn new ones.
Part of http://waynesword.palomar.edu/index.htm, a great site for plant science and botanical ‘gee-wizz’ facts.
If it isn’t on this list, it isn’t. Includes links to online herbariums and the International Plant Name Index.
Another interactive key for finding families; a little easier to use than the one on plantsystemics.org
Mostly good for grasses
More of a poster that has some of the most common families identified by ovary position.
This is the source of our plant handouts.

Video Lectures

Various recorded video llectures on plant science and taxonomy.  

Thursday, April 18, 2013

St. Augustine Needs De-thatching in the Early to Mid Summer


Almost time to de-thatch!

St. Augustine grass (Stenotaphrum secundatum) is coming out of its winter dormancy and beginning to revive as the weather warms.  The return of warm weather means it’s time to take a close look below the surface to see if the lawn has reached at unacceptable level of thatch.  Thatch is organic matter like leaves and grass clippings that have accumulated at soil level but have not fully decayed.  This accumulation of thatch prevents moisture, air, and fertilizer from reaching the roots, causing grass to become weak and subject to pests and disease as the growing season progresses.  Part the blades and take a look.  If the thatch is more than 1/2” thick, it’s time to remediate.


De-thatching is done by combing the lawn vigorously with a stiff-tined rake or mechanical de-thatcher.  Remove the thatch and as little of the grass itself as possible.  New shoots will shortly appear.  The best time to de-thatch - June and July when the weather is warm and growth is vigorous.


St. Augustine grass is native to the Gulf of Mexico, the West Indies and West Africa, growing along sandy beach ridges, limestone shorelines, and salty and fresh water marshes.  St Augustine thrives in warm weather, bright sun, and moist soil in regions of mild winter temperature.  These lawns brown in winter and so are often over-seeded for a green winter appearance, although a much more water saving approach to browning would be to use lawn dye (also known as turf colorant) to maintain St. Augustine’s green appearance.
Because it spreads via the rooting of horizontal above-ground stems called ‘stolons’, St Augustine can be invasive -although nowhere near as invasive as similar grasses like Bermuda and Kikuyu.  And although St. Augustine lawns cannot be called water-saving, some of the newer varieties, like ‘Palmetto’, are a bit less thirsty than the traditional kinds.




Turf colorants:
Article on positive environmental impact of turf colorants:

Google store page for lawn colorants:

Tuesday, April 2, 2013

Rare Opportunity! “Sapphire Tower” About to Bloom at the L.A. Arboretum

Puya alpestris in bloom last year. 



Puya alpestris bud as of 3/30/2013; this bud promises a more spectacular bloom than last year. 

Puya alpestris, an unusual South American succulent from the high, barren slopes of the Andes in southern Chile and Argentina, is now in bud at the Arboretum and will come into full and spectacular bloom in the next week or two.  An almost 6-foot teal-flowered spike emerges from the heavily serrated grey-green leafed base which grows to 2-3 foot high and 3-5 foot wide.  At full bloom, the flower spike will be heavily covered with bell-shaped teal flowers containing startling orange anthers.  The prickly leaves are 1-2 inches at the base and about 2 feet long.  

Puya is a form of bromeliad, the same family as the pineapple.  The Puya alpestris is often sold as, but should not be confused with, its larger relative, the Puya berteroniana.  

In your own garden,  you can use this plant as a complement to cacti and other succulents.  It takes full sun and poor soil and is drought tolerant.  You will need elbow-length gloves, however, to weed around it’s base in order to avoid scapes from the serrated leaves.  It can be propagated by dividing rhizomes or offsets and even by seed.  The plant is suitable for xeriscaping.  While in bloom, the plant is attractive to hummingbirds.

The Puya alpestris does not usually flower every year so make sure you see this unusual teal-flowered plant while the opportunity is here.  You’ll find our “Sapphire Tower” in the Cactus and Succulent Garden. Keep checking here for updates.


South African Bulbs Flowering in the Garden

South African Clivias blooming near the Queen Anne Cottage

Enjoy the blooms now and plan for your fall planting.  Five of the most popular of the South African bulbs, which do very well in Southern California’s mild winters and dry summers, are Watsonia, Sparaxis, Freesia, Clivia, and Amaryllis. These are from the families of Iridaceae and Amaryllidaceae.  Leaves are usually long, cylindrical, strap-shaped.  Most like full sun -but some do well in shade. .


Watsonia flowers tall on branched stems with both evergreen and deciduous species, ranging in colors from white to peach to scarlet.  Stems and leaves can be large, 2 ½ to 4 or 6 feet long.
Sparaxis is notable for its splashes of contrasting colors on blooms which themselves come in a wide range of colors.  They are well-suited to borders and rock gardens and bloom over a long period in late spring.
Freesia are typically white or cream in older varieties with newer hybrids in a wider range of colors.  Freesias will dry up after bloom and tend to self-sow if flowers are not removed.  Freesias are often prized for their fragrance.
Clivia is an exception to the sunshine rule.  While Clivia like light they do not like direct sun.  It is a good companion for ferns and other shade-lovers with its brilliant orange and orange-yellow bloom.
Amaryllis, also called Naked Lady or Belladonna Lily, are dormant now but will spring to life come the hot weather of August with fragrant pink blooms.  They are drought resistant and tolerate almost any soil. They can take full sun but the blooms will last a bit longer in partial shade.
Anaryllis bulbs blooming on the northwest side of the Bauer lawn in August of last year. 

South African bulbs have become increasingly popular with Southern California gardeners as we have come to appreciate their adaptability to our climate and usefulness in our gardens.  There is a wide  choice of bulbs from online sources well beyond the popular five mentioned here.  You might check out the PacificBulbSociety.org for more information on available sources of usual and unusual bulbs.  Many purveyors of bulbs, both online and brick-and-mortar, begin their bulb offerings in July with September being the most popular month for bulb sales, just in time for fall planting.

Friday, March 29, 2013

Tour the Rose Hills Rose Garden with Dr. Tommy Cairns, Author "Modern Roses XI: The World Encyclopedia of Roses" and Ortho's "All About Roses" To Give Tour of Rose Hills Rose Garden, Wednesday April 3rd at 2pm.


Rosarian and author Dr. Tommy Cairns

We've got a treat! This Wednesday's class will be touring the Rose Hills Memorial Park Pageant of Roses rose garden and  our guide will be celebrated rosarian and rose author Dr. Tommy Cairns(check out his bio and and podcast interview at the link below).  We are extremely lucky to have Tommy give us this tour, so please be on time!

We'll meet at the rose garden at 2pm, Wednesday April 3rd. We'll also have a live video feed of the tour at http://www.ustream.tv/channel/the-plant-show






If you have questions you can call me at 626 821-3236  -Frank



Thursday, March 28, 2013

A 1/2 Century Plant

Our 50+ year old Fucraea macdougalii are blooming huge, spectacular, and terminal (the whole plant will die afterwards) flower spikes. Interestingly Fucraea macdougalii bloomed last year at the Mildred Mathias Botanical Garden at UCLA.  Today I received an inquiry from what appears to be the owner of another blooming Fucraea macdougalii:

Q.  I have what appears to be a D. draco plant that is about 18 feet tall. It has a single stem with no branches. About 10 days ago, after growing for about 50 years, it started to produce a massive flower stalk on top of the 18 foot plant. The stalk is about 8 inches in diameter and has grown about 10 feet! That's a foot a day. And it's still growing. 
I believe that after such massive growth the plant will die. Do you have any idea what the species of the plant is--and whether it will die after flowering. I could send you a photo in a separate letter if you're interested.

-Leonard    



Q.   The flowering is not finished, but the plant sure does look like this.  It's surely at least a close relative.  I'd better buy a tombstone.  This plant is a favorite of mine.  The day before flowering began I accidentally hit a plastic golf ball that landed on top of the plant.  The next day the plant erupted in Jack-in-the-beanstalk fashion.  Even the neighbors noticed. This flower stalk is huge.  I locked the back door so the thing couldn't get in the house.  Is there anything in the literature about golf balls making these plants flower (joke)?  I never disturbed the plant before.  Not in 50 years!  Will keep a close eye on it.  It's an astounding growth rate.  A foot a day.  You guys are sharp.  Thanks for  the info. 
                                                                                      -A not so cheery Leonard    



A. I suggest using social media –set up a Furcraea cam to follow the progress and decline of the spectacular bloom. If you get enough traffic to sell advertising you may be able to earn enough money to replace the plant.  In 1999 an infrared webcam set up to follow the progress of the Huntington Garden’s stinky plant bloom was an early internet sensation. ; )


 Furcraea macdougalii's suicidal blooms at the L.A. County Arboretum & Botanic Garden. 

Thursday, March 14, 2013

Mystery Plant Solved

About a week ago I was presented with the below pictures from somebody who wanted to know what the tree was.  They had seen and photographed the tree in Manila, the Phillipines. I observed that the leaves were somewhat like Albizzia julbissen  the Mimosa tree but the flowers appeared totally different. Knowing that the unkown tree was probably in the pea family (Fabaceae) I used www.plantsystemics.org to browse around that family. I found Parkia multijuga but that didn't seem to be exactly what I had. I then entered 'Parkia' into Google image search which brought up an image that looked like the plant I was looking at; Parkia javanica. Parkia javanica is native to southeast Asia and  is used medicinally there to treat Diarrhea and stomach infections. 
Photo of Parkia javanica flowers that I was asked to identify. 

Parkia javanica flowers that I was asked to identify.

Parkia javanica immature flowers. 

Parkia javonica flower that seems half eaten away. 

Sunday, March 10, 2013

Saturday, March 2, 2013

Potpourri of Peacock Platitudes



Our Peafowl are Probably Here to Stay

Besides making it impossible to plant many tender annuals and other plants because of the peafowl's propensity to feed on the tender new growth and flowers of many plants, peafowl at the Arboretum eat bugs, snails, slugs and many other pests that would decimate far more plants than the peacocks could possibly damage. They also feed on snakes which may be why snakes are seldom seen here at the Arboretum. 
  
We Are Not the Only Place In Greater L.A. to Be Blessed with these Fowl  -Here Are Some Other Areas That Have Them:

Victor Heights – a working class section of LA west of Chinatown.  Peacocks are actually part of the neighborhood here; are not unwelcome guests.  They are described as noisy, disruptive, and temperamental but neighbors have grown to accept them.  Eggs are left on porches to hatch, people drive slowly to avoid hitting the peafowl, children collect their feathers, and people enjoying watching the funny mating rituals often performed in the streets.  No one claims ownership over the stubborn and independent peafowl; old-timer residents feel they are their protectors and feed them unsalted shelled peanuts, fruit, dry cat food, birdseed, toasted bread. 

L.A. Times Article on Victor Heights Peafowl: http://articles.latimes.com/2009/may/11/local/me-peacock11

Palos Verdes – peacocks came here in the 1920's when a wealthy landowner was given peacocks as a gift because the area was too quiet.  They Dapplegray neighborhood in Rolling Hills Estates is considered a peafowl protection zone.  Some newer residents are not peacock friendly – there are have peacock hit-and-runs.  Mary Jo Hazard wrote a children’s book called “The Peacocks of Palos Verdes”

Transcript of above:

Arcadia – E.J. “Lucky” Baldwin, founder of Arcadia, imported peacocks while on a trip in India around 1880.  They are very useful for the ranch, eating snakes and snails, and were good watchdogs (alerting when large predators were near with loud cries).  Ownership was a status symbol, and it was fashionable in the late 1800's and early 1900's for well-to-do people to decorate their properties with unique animals.  One source believes Baldwin to be the first to bring peacocks to the continental United States.  One rumor believes Baldwin gave peacocks to Frank Vanderlip, owner of the Palos Verdes peninsula, but they were actually given to Vanderlip by the Wrigley family (chewing gum). The last census of Arboretum peafowl was done almost ten years ago by students from Caltech found over 400 populating the grounds.
L.A. times article on Arcadia Peacocks:

La Canada Flintridge – peacocks came in the early 1900s, when Kansas Judge Edwin Sargent bought the property he found them there. LA attorney Frank P. Doherty bought the land from Sargent in 1936. The peacocks killed and ate rattlesnakes, which were a nuisance in the area.


Santa Susana Pass, Ventura County – Ten years ago the wild peacocks there were causing such a nuisance that some residents complained to the Ventura county animal control officials.  The county rounded up 30 peafowl and removed them to Wildlife Way Station – a refuge for exotic animals in the Angeles National Forest.
Supporters of peafowl like that they kill rattlesnakes and insects, squawk when coyotes are near, and the population seems to be controlling itself.  Non-supporters don’t like the damage to gardens, the noise, and the droppings.

Peafowl Abroad:

Peacocks in China:

The peacock (孔雀) is an earthly manifestation of the heavenly phoenix, and the hundred eyes on its tail are believed to activate fame, luck, promote public admiration and bring positive motives from other people. The peacock is believed to be able to relight the fires of an ailing relationship due to the fiery energy of the animal.

It associated with Guan Yim (goddess of compassion, mercy and kindness); both transmute evil into beauty as the peacock feeds on snakes and Guan Yim helps the suffering thereby turning evil into beauty.
In decorative art, the peacock symbolizes dignity and beauty.

Peacocks in India:

Wild peacocks originated in the deep forests of India; the Indian the peafowl is the national bird of India.  People like having peacocks around because they eat small poisonous snakes and other pests.

Indian blue peacocks are not considered endangered, but the green specie is endangered in southern parts of Asia (mostly in India) due to deforestation and hunting/poaching

Eating peacock:

Peacock served in hotels in China and has been well received for its sweet and fragrant taste and its low fat content.

Eaten in rural areas of Australia; the meat is described as cross between chicken and duck, and quite substantial.  Since the undomesticated peacocks fight constantly in the breeding season, they try to keep those numbers down by eating 2-3 peacocks a year.

Peacock was a popular dish in medieval Europe reserved for the royal and noble classes.  The custom was to serve the bird in its feathers for dramatic display.  According to an article by a gourmand who prepared it the meat is not as good as turkey, goose, or pheasant – and it is rather dry.

Peacock Evolution:

Peacocks have been at the center of the controversy between evolutionists and creationists recently. Previous studies showing that pea hens preferred not to mate with peacocks with a reduced number feather eye-spots. A slew of recent studies, several done here at the Arboretum, have added to what the older studies had concluded. One such such study found that peacocks with the highest eye-spot numbers did not have more mating success than other peacocks. This study was immediately jumped on by creationists as proof against sexual selection. However other recent studies have suggested that a minimum number of eye-spots is necessary, but having more than the minimum does not guarantee additional success. Other studies have found that, besides having the minimum number of spots a peacock with an exceedingly iridescent (iridescence is the glowing, vibrant quality of the peacocks coloration that is the result of the Bragg reflection) eye-spots were more successful at mating. It is thought that the quality of the eye-spots iridescence reflects the overall health and fitness of the male peacock.


Study equating mating success to eye-spot iridescence: http://beheco.oxfordjournals.org/content/18/6/1123.full

Peacock researcher Roslyn Dakin’s blog (from 5/52008 and earlier she blogs about here experience here at the Arboretum):

 Thanks to Arboretum Volunteer Angela Lee for compiling this list. 

Friday, February 22, 2013

Close-up of Abutilon x hybridum Stigma

Abutilon x hybridum stigma close-up taken with my new Digimicro digital microscope.
 
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Mountain Mahogany Mulch Misery

I just had a call from a gentleman in Sunland who wanted to know what a good pesticide for Mountain Mahogany (Cercocarpus betuloides) would be. I asked him what the circumstances were. He told me that he had several mountain mahogany plants on his property, but the one located in a partially shaded area had been infested with some kind of white-fly or scale for almost six months. He recounted how he had applied a product containing imidacloprid ( a 'systemic' insecticide that is closely related chemically to nicotine) and that had helped but it wore off and the problem is just as bad. I started asking him some questions:

  • Q. How often is the plant watered? A. Very little supplemental water. 
  • Q. Have you fed the plant?  A. No
  • Q. Have you mulched the plant well and if so, with what?....
                    Now this last question is a somewhat of a trick question....

He answered that he had mulched his plantings with redwood bark. Mulching is usually a good idea -it helps provide organic material to the soil so that microorganisms beneficial to the plant can increase in the soil. However mulching also produces nitrogen, which can be detrimental to many native California plants...especially plants like Cercocarpus betuloides which have roots that fix the plants own nitrogen. 

So what happens when you mulch a Cercocaprus betuloides with an organic mulch that breaks down to provide nitrogen (a plant whose tissues are chock full of nitrogenous compounds to begin with from its own nitrogen fixing activity)? First you get an increase in green, succulent growth which is attractive to insects like whiteflies, scale, aphids etc. that feed on the food conducting tissue, the phloem, of the plant. To make matters worse besides increasing the plants susceptibility to these insects the increased nitrogen content of the sap caused by the mulch actually helps these pests reproduce! So mulching with a nitrogenous mulch is like pouring gasoline on a brush fire for these plants. Unfortunately for my caller, redwood bark is such an organic mulch (although its nitrogen release is delayed and much slower than other organic mulches), and it can even be toxic to some plants under the right circumstances..so what to use?

 Decomposed granite (D.G.) comes in many different sizes from fine particles that congeal like clay when they dry to almost pebble sized grains. Since D.G. does not break down to provide nitrogen it is ideal for those California natives that fix their own nitrogen and so might suffer if a nitrogenous mulch is applied. So not only is D.G. a good alternative for nitrogen sensitive plants like Cercocarpus but if you're mulching with the smaller, soil-particle sized D.G. you have a situation that can attract native bees which prefer nesting on bare ground. 

Thursday, February 7, 2013

A Request for London Pride

I received a request by phone today for a 'London Pride' Saxifraga and was intrigued by the plants history. Apparently during the dark days of the London Blitz this hardy rock garden plant would be the first to colonize the fresh bomb craters. It's plucky colonization and the rather rapid interval between its appearance and flowering were a source of inspiration to war weary Londoners. It was so inspirational that it inspired a wartime song by composer/playwright Noel Coward. 

Finding a London Pride plant however, was a daunting task. It is not carried by local nurseries (it likes dank, moist environments like London and Ireland) and finding any nurseries in the continental U.S. that did carry the plants was impossible. After much searching  however,  I did find a seed source in Devon, U.K., which was fortuitous because the caller had friends there who could procure them for her. 



Saturday, February 2, 2013

Jack Frost Nipping at Your Nolina...

Frost damaged mango tree.
The recent spate of frost has left many local gardeners tropical and semitropical plants looking dismal, decrepit, and destroyed. But now is not the time to clean house and start over. Many times frost damage is far worse looking than it actually is, and many plants can recover from frost damage if you take some simple steps and refrain from taking others. Here is a list:
Do not prune any frost damage off of your plants until all danger of additional frost has past. The dead and damaged tissue of a frost damaged plant can act as an insulator, protecting the living tissue beneath from further frost damage.

Frost cloth like this is specially designed to keep frost off of the plant while allowing air to flow through. 


Purchase "Frost Cloth" and cover your susceptible plants (including already damaged ones) when frost is predicted.

Spray 'Cloud Cover' or a similar anti-transpirent on your plants. These compounds prevent the plant from drying out when exposed to frost. They are harmless to the plant and give you an extra layer of protection besides the the frost cloth.

Anti-transpirants like 'Cloud Cover' help protect the plant by plugging stomata, the small holes in the leaves and stems of plants, and thus preventing the plant from drying out as the result of frost.

The above actions should help minimize frost damage until all danger of frost has past (here usually mid-March). After that period is over you may need to re-assess what you are planting and where you are planting it.

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Friday, February 1, 2013

Full Moon over Rancho Santa Fe

Q.Are 'Full Moon ' maples (Acer japonicum) suitable for Southern California? If not, What variety of maple do you suggest? I live in The Rancho Santa Fe area of North San Diego county.

A. I've seen 'Full Moon' maples growing in protected spots or as bonsais here in Southern California. If you decide to grow them you should keep them in pots located in protected areas with filtered shade; also when they grow here their leaves tend to burn starting about mid-summer.

If that's not discouraging enough there’s another problem now –many maple species here are under attack by a pest called the Polyphagous Shot Hole Borer. This beetle has been killing maples here and will probably only get worse, so you taking a big gamble no matter what maple you plant. The pest is currently not in San Diego County but at the current rate of spread may soon be.  

University of Conneticut Horticultural Information Page:


Mendecino Maples Acer japonicum selection:


 

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