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)

Wednesday, October 11, 2017

Around the Arboretum -Early October

Mushrooms (probably Agaricus sp.) 'flushing' near the administration building. 

Mexican sage (foreground) ; Rainbow gum (tree in the background)

Can you see the Freeman's maples starting to turn color?

Madagascar Moringa tree and leafless Plumbago. 

Looking north from the road in front of the Cafe. 

Yellow Golden rain tree flowers. 

Nandina domestica (Heavenly bamboo) turning bright red and orange for the fall. 

Ceiba speciosa (Silk floss tree). 

Bauer fountain. 

Bauer fountain. 

The Canada geese are back!

Saturday, August 26, 2017

Wooly Oak Aphids

I received a call from a client who complained that their oak tree was dropping fuzzy stuff all over the area underneath its canopy. I asked them to bring it in and this is what I saw:

Leaf with cottony wax and visible aphids. 

I then put it under a magnifying scope and was able to see the culprit:

Closeup showing (l) aphid, (r) egg surrounded by waxy 'wool' produced by the aphids.

It was Wooly Oak Aphid, one of a pantheon of insect pests that attacks oaks. Like many pests on oak it is mostly not a threat, just a nuisance. Time is the usual insecticide, with infestations resolving themselves within a month or two when increasing attacks by predators and the changing physiology of the oak itself lead to its demise.

Links to more information on the Woolly Oak Aphid:

Woolly Oak Aphids - BugGuide.Net
woolly oak aphids, Stegophylla brevirostris, on black oak leaf. - YouTube
Aphids Management Guidelines--UC IPM
woolly oak aphids -Stegophylla brevirostris Quednau and Diphyllaphis microtrema Quednau
Dancing woolly aphids will probably stab you - Scientific American Blog Network

Friday, August 25, 2017

A Handful of Climate Appropriate Trees

The following trees have been picked because they are relatively climate appropriate. Keep in mind that 'climate appropriate' means more than just low water use. Many east coast and european trees require not only water but also cold winters in order to remain healthy. Also, many tropical trees are frost sensitive here and have problems with frost either killing or damaging them. To find a specimen of these trees here at the Arboretum just click on the icon for that tree in the map above. For more information on each tree just click on the link associated with its name and it will take you to the Cal Poly Selectree Database entry for that tree if it exists. 

Afrocarpus falcatus

Geijera parviflora

Melaleuca linariifolia

Lagerstroemia indica

Citrus and other Fruit Trees

Ceiba speciosa (Chorisia speciosa)

Moringa hildebrandtii

Brachychiton rupestris

Callistemon viminalis 'Red Cascade'

Eucalyptus torquata

Corymbia (Eucalyptus) citriodora

Cedrus atlantica

Draceana draco

Olea europaea ssp africanus

Sequoia sempervirens

Quercus polymorpha

Quercus  rhysophylla

Platanus mexicana

Tuesday, August 22, 2017

LAist Names Us One of the Best Places in L.A. to Watch Birds

Bluebird at the Arboretum

Popular Los Angeles blog has named the Arboretum one of the best places to watch birds. We are also listed by the Pasadena Audubon Society as one of the best places to watch birds as well.  There have been over 250 species of birds observed here, so, yes we are.

This is great news, I'm going to tweet it. 😁

Tuesday, August 15, 2017

Glassy Winged Sharpshooter

Glassy Winged Sharpshooter

I had several of these brought into my office several days ago. They are partly responsible for the demise of Oleanders all across Southern California. Their feeding activity centers around the water conducting tissue in the plant they are attacking. The orange bulb shaped area that you see on the bottom of the leafhopper in the picture is its 'head pump', a muscular organ that helps the insect pump the watery xylem fluid (mostly water coming from the roots) from the plant and through its body. 

Glassy Winged Sharpshooter
This feeding method means that it doesn't have to compete with sap sucking insects like aphids and scale, but it does require the insect to process a lot of fluid through its digestive track because xylem fluid is lean on nutrients like sugar and dissolved nitrogen compounds. This causes if to expel water out of its anus like crazy, as can be seen in this video. These insects are partly or mostly responsible for trees that 'rain' drops of fluid down around you in the summertime. 

Should you control these pests? Generally, no. However if the squirting gets to be too much you might try a pyrethrum based organic control like Pyganic, however be very selective as far as what and where you spray because this insecticide, like many pyrethrum based products, will eliminate beneficial and predatory insects as well as the pest.

Wednesday, July 19, 2017

What Is There To Do and See at the L.A. County Arboretum & Botanic Garden When it’s really Hot?

It’s Summer here at the Arboretum. This time of year can be hot -we just had some pretty healthy 105 degree plus days. Besides slathering on sunscreen, wearing cool clothing, carrying (and drinking) plenty of water and fluids,  and wearing a hat or carrying a sun blocking umbrella, what can you do to really enjoy your day here besides the usual survival 101 skills?

Plan to visit areas that are shady and cool!  We have compiled a list of the 7 coolest places in the Arboretum so that you don’t have to wait for cooler weather to visit. So here are the 7 coolest places in the Arboretum, from furthest to closest:

1. Meyberg Falls
2. The Historic Section
3. The Bamboo Grove
4. The Tropical Rainforest
5. The Tropical Greenhouse
6. The Celebration Garden
7. The Arboretum Library

Let’s take a look.

Meyberg Falls 

Meyberg Falls

On just about any day here at the Arboretum you can find a dozen or more people hanging out here. Besides visitors, it’s popular with wedding photographers, music video producers and feature film makers. Katy Perry’s ‘Roar’ Video, Beyonce’s ‘Survivor’ video and the Rock video scene in “Wayne’s World” were just some of the many that were filmed there.
Lucky Baldwin's Queen Anne Cottage

The Historic Section

When San Francisco hotelier and millionaire Lucky Baldwin decided to invest in property here in the L.A. area, the Santa Anita ranch was one of the first purchases he made. Lucky’s ranch was surrounded by dry communities, so alcohol, gaming and horse racing were regular activities. To raise his ranch’s status above that of a mere roadhouse he featured fine varietal wines, a first class hotel, and to attract a higher class of clientele, authors, actors, opera singers and other celebrities of the day as featured guests. These celebs would stay at Lucky’s Queen Anne Cottage and give lectures, recitals and concerts to attract the staid citizens of the surrounding towns.

This historic section of the Arboretum is planted with many large trees, many over 100 years old, that provide shade -and a large lawn that is popular with weddings and other events.

Shady path through a bamboo grove here. 

The Bamboo Grove

The Arboretum has many exemplary collections, including over 60 different species of bamboo. Some of these bamboo, like Phyllostachys aurea, have formed dense and shady groves where you can duck in and avoid the sun in a cool, green forests of the grassy plants. The interiors of these groves can resemble green caverns and they are very popular with videographers, photographers and artists. A word of warning; be careful of the many small, stake-like stumps that can pose a tripping hazard.
The Tropical Rainforest

The Tropical Rainforest

Situated on the North side of Baldwin lake, the Tropical Rainforest is an area that represents the forests of the tropics and subtropics. Situated under tall Cypress trees from the American South and Mexico, this shaded paradise contains a collection of cycads, a grove of bamboo, and a disparate collection of tropical trees from around the world. There are several benches located in the forest, making it the perfect place to sit down and relax.
Inside the Tropical Greenhouse

The Tropical Greenhouse

When the weather is boiling hot the Tropical Greenhouse, located to the North of the main entrance, is not. That’s because it is usually kept to a constant temperature somewhere around 85 degrees -a relative ice box when the temperature is hovering around 105. Inside are orchids, ferns, bromeliads and even a Cocoa tree, the source of chocolate.

Small courtyard fountain in the Demonstration Garden. 
Top of the Weeping Fountain in Lew Watanabe's meditation garden vignette in the Demonstration Garden. 

The Celebration Garden

This area is a cool collection of shaded ‘vignette’ gardens that used to make up the Sunset demonstration garden, an area originally envisioned in the envisioned as being a demonstration and an inspiration to do-it-yourself landscapers. It’s last refurbishing, back in 1998, featured vignettes from cutting edge landscape architects and designers. Still visible today are a shady lawn garden, a courtyard fountain garden, a low water use deck area that uses synthetic recycled deck elements, a California native garden that uses polished granite as a faux stream, a shaded walk among California coastal redwoods and Canary Island pines, and finally a traditional Japanese meditation garden fashioned by the late Sierra Madre garden designer Lew Watanabe. Lew’s garden contains an example of his signature ‘weeping wall’ fountains, granite sculptures that are painstakingly made level so that the water pumped out the top covers the top and side of the fountain with a thin film of flowing water.

The Arboretum Horticultural Library

The Arboretum Horticultural Library

One of the finest collections of horticultural and botanical texts on the west coast, it is also a fine example of mid-century modern architecture.

A recent remodel has rendered its interior space true to its mid-century roots. Come inside and see the newly revealed vaulted ceiling, true-to-period lamps and furniture and spacious, yet less claustrophobic book shelving. Say 'Hi' to myself and librarian Susan Eubank. And, most importantly, enjoy the massively effective air conditioning.

Map to the Above Locations

Tuesday, July 18, 2017

I Go To a Friend's House to Settle an Argument and End Up Giving Them Way More Grief Than Even I Expected

I went to a friends house for lunch to check out a tree. The situation was that he and his wife had a little disagreement about whether or not a branch should be cut from it. I wasn't looking forward to being in the middle of a spousal disagreement but I knew my friend and his wife and didn't think it would be a big thing. The tree in  question is a California pepper (Schinus molle). The trees common name is a misnomer, as it is native to Peru. If the number of questions I receive about it is any clue, it is one of the most problematic trees in Southern California as well as one of the most popular. Since before the turn of the century, and maybe even since the early 1800's, these trees have graced ranchos and farms here. Unfortunately they can be very short lived if they are watered too frequently, sometimes only 40 years before rot starts causing large limbs to fall off.

My friend's California pepper tree. 

At first glance my friends tree seemed fine. It was just over five years old and had a large canopy, probably 30-40 feet wide, and the canopy was lush and luxuriant. The branch in question could have been pruned off or left as is, so I didn't have to take sides in my friend and his wife's argument. But there was something else...

I first noticed that some string lighting that had been placed on the tree was cutting into the trunk, so I mentioned it should be removed. Secondly, the tree was in a lawn, California pepper trees should not be planted in lawns, nor should lawns be planted around them. I then noticed something far more serious: the tree had a defect that could not be resolved and would result in my recommending the tree be removed.

Looking at the base I noticed a problem that has no happy ending -the trunk was an even diameter from about 8 feet up to where it entered the soil. It had no flair. Lack of any flair at the base of the trunk generally means that the tree is doomed to failure way before its time. It is caused by planting a tree that is rootbound. This sets up a situation where the trees own roots literally strangle the tree's trunk, preventing it from growing wide at its base. This messes with the fundamental physics of the tree.

Trees need a flaring base so that the roots coming from the base can form a 'plate' under the ground that  helps support the tree. This is so the center of gravity of the tree is always above the roots that are supporting it. If the center of gravity is allowed to lean over that support and becomes positioned over soil where their are no large roots to provide a surface for the tree's weight to act on it through the force of friction, then there is nothing keeping that tree up and it fails.

Now add to that the effect that the much narrower than normal trunk has on the tree -it raises its center of gravity. So where a normal tree would have a center of gravity that's maybe about a normal person's shoulder height it instead has a center of gravity located up in the canopy of the tree so that it is much easier for the wind to push the tree's center of gravity over the supporting root area and cause the tree to fail. The tree is basically too top heavy.

But that was not all, it was also showing signs of imminent failure. The tree had a noticeable lean and opposite the lean a mound had developed adjacent to the tree. This may indicate that the tree is already starting to fail; the weight of the tree could be pulling these vitally important supporting roots straight out of the ground.

So my recommendation was, unfortunately, to remove the tree and either plant a new one or choose another type of tree and plant that instead. In my next blog entry I will discuss some of my favorite trees for backyard shade, so stay tuned.

Also notice the tree is leaning to the left.