Friday, January 5, 2018

Thursday, January 4, 2018

Sprall Has Sprung

It has been pretty wierd weather-wise here at the Arboretum. The drought that briefly retreated last year is back. It's itchy dry, and only recently have the evenings been cool enough to get the fall color change going. Not only has the weather been cool enough to finally kick start fall (about a month ago), but just recently I've seen plants blooming that usually don't start to do so until late February. One of those is the Pink Trumpet tree (Tabebuia impetiginosa), probably one of the most noticeable tree here at the Arboretum from late February until early May when it blooms with a thick coat of pink trumpet-shaped blooms and nothing else -prefering to leaf out just after the bloom on the trees have peaked. 

Now, however, it is starting to bloom. I cannot remember a season so early for them in the 20 + years I have been at the Arboretum. I've also observed flowering almonds blooming (usually a late January to mid-February occurrence) and at the same time turning fall color (see photo below). 

Since we haven't had much of a winter yet (although that could change), I am proposing that these phenomena I am seeing, fall color occurring at the same time as spring bloom, constitute evidence of a new season heretofore unknown: "Sprall" (pronounced "Spawl"). The word is a combination of Spring and Fall and would accurately describe the mixed up occurance of bloom and fall color that I have just recently seen here. 

Now I'm not one to over-react to seemingly weird weather here. I've been a resident of Southern California since I was born and am quite used to pretty wide fluctuations in the the climactic changes that we pass off as seasons. However, this last one is quite unique, and deserves some notice, and definitely its own name. 

Flowering almond showing both spring flowers and fall color. 

Tabebuia impetiginosa with both fall color and spring bloom. 
However, even though the spring color is months early, the fall color is months late. 

Viburnum  macrocephalum, the Chinese snowball blooming at the same time that Ginkgo biloba fall color is peaking (the yellow in the background is a display of golden Ginkgo leaves). I cannot recall Viburnum macrocephalum blooming so early. 

Tuesday, December 26, 2017

A New Insect That Sucks (but does little else)

About a week ago Tim Chenowith, one of our Arboretum gardeners, brought a new pest to my attention. It appeared to be some sort of sucking insect that was peppering the Senna wislezini that is part of our Southwest collection near the Rose Garden. At first I thought it was an aphid, however It did not have the two spiracles, sharp protuberances that occur on the rear of the insect, that are key identifying marks of most aphids. It was also unusual in that the ‘honeydew’ it produced was solid, and stayed on the bugs rear end until it broke off, in which case it would stick to the plant that the bug was infesting almost like sugar crystals but a little more oval in appearance. Since I hadn’t seen this pest before I did what I usually do faced with an unidentifiable pest; I sent a picture of it to Gevork Arakelian, the entomologist for Los Angeles County’s Agricultural Commissioner Weights and Measures office.
Small insect peppers this Senna with small balls of solid sugar. 
In the old days I would send the whole pest and it would be relatively involved process of sending via the county courier, the County’s own parcel post and letter delivery service. Although most times it would get to the Ag Commissioner's office intact, if I had to send the package containing the live pest on a Friday it would not get opened until Monday -sometimes resulting in an indiscernible mass of what was, just several days before, once a living pest. Now it’s pretty easy, I just position my iPhone a half an inch above the eyepiece of my microscope and take a pic. The result is then photoshopped until all the highlights, furrows, ridges, antennae and other insect parts that Gevork might need for an ID are mostly visible.

At the top is one of the insects, the thing on its rear end is a mass of solid honeydew. The white masses are surrounding the four insects in the picture are solid honeydew produced as the result of the pest excreting a sugary waste out of its rear end.  

 Gevork got back to me the the next day. He pretty much nailed it. It was a Caesalpinza psyllid, a small sucking insect that apparently causes little or no damage to its host. here is the description he sent me:

 CAESALPINZA PSYLLID, Freysuila dugesii, -(Q)-This psyllid is one of several in the genus that feed on leguminous shrubs and trees in Caesalpinia and Poinciana. The first California record comes from Palm Desert, Riverside County, where it was collected on a golf course by County Ag Biologist Richard Shaffer in January. The host was Caesalpinia cacalaco. This small shrublike plant with yellow and orange flowers is being commonly planted these days in many southern California and Arizona locations. Our specimens were confirmed by Dr. Ian Hodkinson in England. Little is known about this psyllid as it has been collected only sparingly over the years. It is most likely native to Mexico, the native home of the host. No apparent injury such as galling or malformations to the plants were noted. It is likely restricted to these hosts and whether it will cause damage to them in the future in ornamental plantings is unknown.

This also makes sense because Senna wislezini is closely related to the host, Caesalpinia cacalaco. It might infest Mexican Bird of Paradise plants (Caesalpinia pulcherrima), but if it did it would probably not damage the plants.    So thankfully this pest is probably nothing to worry about, but I'll keep an eye on it. Interestingly the coating of sticky solid honeydew balls could be a manner of camouflage for the pest, making it tough for birds to discern the sticky sugar balls from the psyllid.

Tuesday, November 28, 2017

Meyer Lemon Turns Green -Is it Infected With Yellow Dragon Disease?

I was sent this pic by a client who wondered if the green skin of this Meyer lemon meant that it had Huanglongbing disease, a malady that is threatening Southern California's citrus groves. He also added that other than the green skin, the lemon tasted the same. 

Well this citrus probably does not have Huanglongbing. The greening associated with the disease is usually very uneven. What is happening is probably a process called 're-greening' that is common in some oranges, like Valencias. After the oranges ripen their skins start turning green again. This does not change the sweetness of the orange or its taste. This 're-greening' can happen to Meyer lemons, because they are actually oranges that taste and look like lemons. Also, 're-greening' occurs more frequently during warm winters, which we are currently experiencing. 

Thursday, October 19, 2017

Harbingers of Fall

It's coming up on the season here in the L.A. area that seems to resemble Autumn. There is discernable change in some of the plants that originate in temperate areas. That change can resemble the classic fall color change with vivid hues of orange, red, and yellow -or it can be a ripening and drying out that can look similarly spectacular. Above are cardoon plants whose flower heads have dried to create star-like straw-yellow seed heads. 
Another angel on the cardoon plants with their straw colored seed heads in the Herb Garden. 

Of course this is Southern California, and although we've renamed brown 'gold' to cope with the long (up to 9 months) dry season, just add a little water and flowering trees will do their thing here. The fabulous pink flowered Floss silk trees (Ceiba speciosa) reliably bloom just around world series time. This one is located just north of the cactus and succulent garden. 

Another view of the Ceiba speciosa located north of the Cactus and Succulent garden. Notice the karst river stone with viewing hole. 

One of our most impressive specimens of Ceiba speciosa stands just east of the gateway fountain and greets Arboretum visitors as the enter. It is a variety introduced by the Arboretum in the 80's called 'September Splendor'.

This really impressive patch of Japanese anemone is hidden somewhere between the Korean steeles and Meyberg falls. 

Right now is a great time to do some hummingbird watching. There are several different species clamoring for one of their favorite nectar sources; the Mexican sage (Salvia leucantha)