Tuesday, December 20, 2016

Assassin's Creed

Assassin Bug (Nymph)

Just in time for the release of the "Assasin's Creed" movie I received this picture of a bug to identify. Turns out it is not only a 'bug', but a true bug, a member of the order Hemiptera, a large order of piercing sucking insects that includes aphids and bed bugs. This one is a little more welcome than the previously mentioned bugs: it's a predator of aphids and other harmful insects.

Thursday, December 15, 2016

Jawdropping Fall Color at the Arboretum

There, I've used a Buzzfeed keyword; it is well deserved however. Right now we're probably looking at the last gasp of really spectacular fall color until next year; this is because the heavy rain predicted for this evening may just well knock off most of the fall foliage that is currently peaking here at the Arboretum.
A species Liquidambar near the Peacock cafe. 

Crepe myrtle in full color near the Peacock Cafe. 

Aloes starting to bloom in the South African section. 

Crepe myrtle (right) and Persian ironwood (left)

Persian ironwood. 

Wild wisteria vine growing on trees on the north edge of the Tropical forest section. 

Wild wisteria and wild grape vines clambering on foliage on the north side of the Tropical forest. 

Pink Handroanthus paulensis blooms (right) surrounded by white Shaving brush tree blooms. 

Pink Handroanthus paulensis  and white Pseudobombax ellipticum blooms on the east shore of the Baldwin lagoon. 

Ginkgo biloba tree framing Cycads. 

Ginkgo biloba tree framing Cycads. 

Friday, November 18, 2016

Another species of Varroa mite threatens European honeybees (from Science Daily)

(Please keep in mind that science journalism has become a little more sensationalized than it once was)

From Science Daily:

  Another species of Varroa mite threatens European honeybees: A sister species of the Varroa destructor mite is developing the ability to parasitize European honeybees, threatening pollinators already hard pressed by pesticides, nutritional deficiencies and disease, a study says.

Wednesday, November 9, 2016

A Not So Great Crepe Myrtle


Thank you for your time.  I purchased a crape myrtle last summer and it did well for a few months.  During dormancy I did not water it very much and this spring it really looked puny.
 I was told by a neighbor that has healthy nice crape myrtles that it needed a lot more water than I was giving it;  30 gallons a week during dormancy and up to 60 gallons per week during the summer months.
 My tree originally came in a 42 inch box and is now about 18-20 feet high.

Thank You, Maria

Hi Maria,
Could you answer some questions for me?
              1.      Has the tree progressed much at all from the size they were in the box?
2.      Did you fertilize the tree when you planted it? If so, with what?
3.      What was the average temperature for the next several weeks after you planted it (roughly)?
4.      When you dug out the hole for the box, did you dig it deeper than the depth of the box?
5.      What kind of amendment (if any) did you use in the hole? What percentage soil and what percentage amendment?

Cheers,   Frank

Hi Frank,
 I can answer some of the questions but not all.  I purchased the tree from --------,  and they dug the hole amended the soil and fertilized my tree.
 I of course watched and the hole was at least the depth of the box if not more so.
They gave me a liquid fertilizer to use once a month and I have added worm castings periodically.
 She was my 60th birthday present to myself and I hate to think that she isn't thriving and as beautiful as she should be.  I will say that she did flower beautifully for about a month this summer but she isn't very full as far as leaves go.
Thank you for your patience and help.


Hi Maria,

 Amending the soil is not recommended when you plant a crepe myrtle. Also, fertilizing any tree when it’s planted can be harmful to the tree. The fertilizer can cause a condition where the fertilizer salts burn the roots, causing them to form a type of scar tissue that can dwarf the tree and stunt its growth for the rest of its life.
Also, the ideal size to start a crepe myrtle out (or any tree for that matter) is a five gallon or smaller container. The larger the container, the more of a possibility the plant is going to be root bound and do poorly, plants in smaller containers naturally establish better than ones in larger containers.
The once a month fertilizing is way too much for the plant. Most ornamental trees and shrubs should only be fertilized once in their lifetimes, usually between 9 months and 1 year after they are established.

Cheers,   Frank

Hi Frank,

Okay thank you then I will stop fertilizing her. What do you think about the water amount and also do I water at all during dormancy?


Hi Maria,

Create a watering basin around your tree (see item number 4 on this link) –fill it with water by hand every week until the rains come.  Start watering again in the mid to late spring.

Cheers,   Frank

Saturday, October 22, 2016

Low Carbon Footprint Trees Links

Low Carbon Footprint Trees Talk Links:

Carbon dioxide emission footprint calculator and offset estimator
Formula calculates how much water each tree needs - Midland Reporter-Telegram
Hw much to water trees: SN900A_How-Much-Water.pdf
Irrigating Citrus Trees: az1151.pdf
Coast Live Oak Care and Management: cs_quag.pdf
UFEI - SelecTree: A Tree Selection Guide
Pacific Horticulture Society | The Most Majestic Southern California Oak
Oaks And Carbon Sequestration
UFEI - SelecTree: A Tree Selection Guide Quercus engelmannii
Mexican White Oak Growth Rate | Home Guides | SF Gate
Global Species : Quercus polymorpha (Mexican White Oak)
Article about carbon storing trees -most of these are terrible for Southern California: Eartheasy Blog » 10 Carbon-Storing Trees, and How to Plant Them
CarbonFootprintof of Water-RiverNetwork-2009.pdf
Impacts of Urban Water Conservation Strategies on Energy, Greenhouse Gas Emissions, and Health: Making the case for recycled water: Southern California as a Case Study
Despite their huge psychological benefits, lawns are terrible wasters of water and producers of CO2 according to this article: Urban parks: a global warming downer? | Greenspace | Los Angeles Times
El Paso's favorite trees here: Texas Tree Facts
Find out what your Carbon Footprint is: CoolClimate Calculator

Englemann Oaks

Planting Engelmann Oaks
Our own senior biologist, Dr. Jim Henrich, tells us why Engelmann oaks are one of his favorites: Engelmann oaks, better than beautiful | L.A. at Home | Los Angeles Times

Saturday, October 15, 2016

Links For Hipster Horticulture: Botany Boot Camp










Friday, October 14, 2016

What's Blooming at the L.A. Arboretum and Botanic Garden, October 14th 2016

Ceiba (form. Chorisia) speciosa

Floss-silk trees as they are commonly known can be highly variable as to when they start blooming, but since I've been here (1998) they have always been consistently blooming when the World Series comes around.  In the photo below you will see at least two of the four varieties that the Arboretum introduced around the early 1980's; September Splendor and Arcadia. 
Left to right: September splendor, Arcadia

Ceiba speciosa 'Arcadia'

Tabebuia avellanedae var. paulensis 

Identified here as Tabebuia impetiginosa 'Paulensis', this seems a miniature version of Handroanthus impetiginosa. It usually blooms several months earlier than the latter and its blooms can be far more dense. For more info on these beautiful trees see Matt Ritter's article in Pacific Horticulture. 

Tabebuia avellanedae var. paulensis

Pallenis maritima the 'Gold Coin' plant

Pallenis maritima the 'Gold Coin' plant

This tough, salt resistant native to the Canary Islands and the west Atlantic coast of southern Europe and northern Africa blooms Spring and Fall and in between.

For locations of the plants mentioned above and more currently blooming plants check out this map of blooming plants here at the Arboretum (you can use the share feature below to email the map to you smart phone and use it to navigate to the plants):

Wednesday, September 7, 2016

Q. I would like to know the latest information regarding beetles attacking southern California trees and if there is anything that can be done to cure the problem.

A. There are normally hundreds of different types of beetles that attack trees here in Southern California, in fact beetle attack is a normal stage in the life cycle of most trees in the wild. Without beetles attacking trees that are stressed and dying they would take far longer to decompose after the trees have died, and therefore it would take longer for the new trees replacing them to establish.

This normal beetle activity accelerates when stress on the trees accelerates, which is what's happening now because of the current severe drought. When most of the trees in a forest are stressed, the beetles numbers increase to a point where they are so large that even a healthy tree can't repel them.

But there's more. The current level of trade from around the world has increased the number of new beetles that have no natural checks and balances (most of our native  beetles are normally kept in check by parasites and predators that feed on them). One example is the Polyphagous Shot Hole Borer (PSHB). The pest was only discovered in 2012 and since then has caused the loss of thousands of trees from the urban canopy here. Since this pest also threatens the $Billion+ avocado industry, there has been significant resources channeled to its control. Still, there does not seem to be an effective control against it, although several compounds are being looked at and an effort is being made to identify predators and/or parasites that can naturally control the pest. Currently it attacks over 100 types of trees and large shrubs, and its host list (the plants it can reproduce in and spread the infestation) has swollen from 22 in 2012 to over 40 now.

What's the answer then? Short term finding controls is important, but it does not solve the problem. The biggest problem and one of the big reasons that the shot hole borer and other pests are getting such a foothold here is the urban forest canopy itself.
Many of our trees are clonal, they are basically the same tree. That is what ornamental horticulture is about is reproducing clones of plants that have the most desirable traits you are looking for. This make for easy pickings for pests because there is no difference in the plants ability (or lack of it) to resist the pest that is attacking. This makes for large numbers of pests and favors the those offspring that are particularly good at attacking and reproducing.
Also our own urban canopy is made up of trees that have evolved to take advantage of climates that are totally unlike ours. For example the beautiful fall color turning tree Liquidambar styraciflua originated from the South eastern coast of the United States. That area has copious amounts of rainfall throughout the summer, unlike Southern California where summers are hot and dry. Why does it do so well here? Two reasons; 1. Irrigation which allows us to grow species of trees that otherwise would not establish here 2. Lack of pests due to the fact that the plant is grown in an area where its native pests are absent. Both of these conditions are unsustainable in the long run and the only cure is to select trees that actually do well with the amount of water that is naturally available here.  We will still get new pests but the trees will not be stressed and therefore huge plague-like infestations like the current PSHB infestation are less likely to happen. That does leave us with a much smaller selection of trees to plant, but if we do that we can enjoy a good looking and long lasting landscape dotted with trees.

Cheers,   Frank

Thursday, September 1, 2016

What's Blooming at the Los Angeles County Arboretum and Botanic Garden this Labor Day Weekend?

If you open this page on your smart phone, just click on the little square in the upper right-hand corner of the embedded map and it should open up in Google Maps, then you can navigate to the plants. If you are reading this on your home computer or pad, just click on the share symbol (looks like a '<' with little circles on the ends and on the apex) and email the link to the map to an email address that you can open in your smart phone with Google Maps. Open the email that you just emailed yourself on your smart phone and click on the link and the map should open in Google maps. Once the map is open in Google maps you can navigate to the different markers to see what's blooming!


Thursday, August 25, 2016

What's Growing in the Lake?

Our once perennial Baldwin Lake has been extreamely low for more than several months due to the current drought. Walking by the lake the other day I couldn't help but notice the plants newly colonizing the lake bed. What are these plants and how did they get there?

Newly established plants colonizing the Baldwin lakebed. Birds carry the seeds. 

Persicaria lapathifolia, commonly known as 'Smartweed' has a history of use as a grain and a medicine by Native Americans in the in the East, Southwest and Midwest parts of this country. It is a North American native  plant that likes disturbed places and wast land and has become a noxious weed in Europe. 

Persicaria lapathifolia

Catharanthus roseus; this is the garden annual known as 'Vinca' or 'Periwinkle' The seeds are small and can be carried by birds that eat insects that are feeding on the periwinkles. 

Salix laevigata the native Red willow. The seeds of this plant are dispersed by the wind and may have come from established plants located near the upper part of the lake. 

A Chenopodium sp., commonly called "Goosefoot". Chenopodiums are common weeds of waste areas. Birds and humans can disperse the seed. 

Portulaca oleracea. Portulaca is a common lawn weed that is quite edible.Seeds are small and can hitch a ride on birds, animals and humans.  

Portulaca oleracea closeup

Epilobium possibly E. ciliatum. Epilobiums are known as 'Fireweeds' because of their affinity for burned or disturbed areas. Seeds are dispersed via the wind and can blow for miles. 

Dysphania ambrosiodes, is also known as the "Epizote" and is one of the ingredients in the hangover cure Menudo. The seeds of this plant are very small and can be dispersed via dirt in the tread on shoe soles. 

Ubiquitous palm seedlings, probably Washingtonia robusta, the Mexican fan palm. These seedlings are no doubt the result of the copious fruits that drop from the dozens of trees surrounding the lake. 

Possible Lactuca sp., spread by the wind. 

Looks like a sunflower but most probably Paulownia tomentosa seedlings.  Paulownia seeds are winged and easily dispersed by the wind. They germinate immediately upon being dispersed (usually in the summertime). 

Prickly lettuce, Lactuca serriola. Lactuca is spread mainly by the wind, having seeds somewhat like dandelions. These plants may have come from nearby ones growing in the adobe excavation area. 

Either a walnut seedling or Ailanthus altissima, the 'Tree of Heaven'. Sniff test confirms -the leaves smell like rancid peanut butter. 

Ailanthus altissima seeds are contained in a wing-like membrane and can travel almost 300 feet from the parent plant. 

Most probably 'Barnyard grass' a common weed of cultivated areas. The seeds are buoyant, and are able to float great distances in water. 

Cyperus involucratus. An accesioned plant, however this one is a volunteer. 

Cyperus papyrus, the Papyrus plant. This too is a volunteer from an accessioned plant. Animals eating the tubers of this plant may have been responsible for spreading, or it could have hitchhiked on gardener's tools.