Six on Saturday: Joshua Tree

Yucca brevifolia is commonly known as Joshua tree. It is native to the Mojave Desert. It is very rare in home gardens because it is so extremely susceptible to rot with irrigation, or even where it gets more rain than it is accustomed to in the Mojave Desert. Besides, it is very difficult to work with, and even with impeccable maintenance, even the healthiest of specimens develop weirdly and unpredictably irregular form that too many find to be unappealing. Nonetheless, whether appealing or otherwise, whether in a landscape or in the wild, it is a fascinating species of Yucca. Rhody and I encountered these Joshua trees and many others west of Boron last Thursday.

1. Joshua tree is the tallest tree in this region, but does not get as tall as utility poles. The scarcity of moisture limits vegetation here. That is not wildlife in the lower right corner.

2. Zooming in on the specimen to the right in the previous picture reveals that there are many more in the distance. Many are solitary. Most live socially, in otherworldly forests.

3. If there were an exemplary Joshua tree, it might look something like this. The shabby specimen in the background to the right is also rather typical. They are weirdly variable.

4. These short and rigid leaves are extremely sharp! They look somewhat like the foliage of common giant yucca, but are very difficult to handle. Joshua tree is better in the wild.

5. Old foliage decays very slowly. It folds back and lingers on the limbs like this for many years. Joshua tree grows very slowly, so this foliage may have been like this for decades.

6. Trunks eventually shed deteriorated old leaves as they widen and develop this roughly textured exterior that resembles bark. Again, that is not wildlife in the lower left corner.

This is the link for Six on Saturday, for anyone else who would like to participate:


Six on Saturday: Tequila


If one of these six different agaves happens to be the blue agave from which tequila is made, I would not know. I only know that all six are various specie or cultivars of the Agave genus. The sixth picture is that of the common century plant, Agave americana, which is not used for tequila. I have no idea what the other five are. The fifth looks like it could possibly be a picture of Agave victoriae, but if I remember correctly, I was specifically told that it is not.

All six of these agaves were procured by my colleague. The first specimen is still potted at the shops where we work. The second specimen was relocated into a new landscape early last spring. The other four are within minimal proximity of each other, in a more established part of the landscape. There happens to be two agave pups in the Infirmary Nursery. At least one is from the agave in the second picture. I believe that the second pup is the same as well, but it seems to be developing teeth.

The wickedly sharp teeth and spines of most specie of agave are the main reason that agaves are not more practical in home gardens or small landscapes. It is not practical to try to snip the terminal spines off, because more develop with every new leaf. If they get enough space out of the way, agaves are bold and remarkably striking big perennials that are very resilient to arid climates.

There are no captions this week, because I do not know what to say about agaves that I know nothing about.







This is the link for Six on Saturday, for anyone else who would like to participate:



That is what this seemingly disorganized jumble of letters and numbers represents; the chemical formula for the mineral known as trona. It is what a certain small town in the very northwestern corner of San Bernardino County is named for. Trona is one of a few minerals mined and refined there. Apparently, not much else happens there.

Trona the town is about as out of the way as one can get in the contiguous United States of American. Death Valley to the northeast at least gets tourists. Not much flora survives in the hellish summer heat and caustically saline soil. The athletic field at Trona High School is famous for being grassless dirt. Even the now defunct golf course was dirt. Roofs are more important for providing shade than for keeping the four inches of annual rainfall out. A leaky house is more likely to petrify before it rots. The inertly arid air, roasting heat and acrid drifting minerals seems to sterilize and embalm even abandoned houses. The Google Satellite image shows how boringly uniform the factory tract houses are. Many are now abandoned. Some are missing.

Why am I mentioning Trona here? Because horticulture is so limited in Trona. There might not be many better places in America for a horticulturist who lives amongst dense forests of the tallest trees in the world to go on vacation! There are so few distractions! The vast desert extends for miles in every direction, with only a few plants surviving in home gardens in town. The satellite image shows how empty the gardens are. A single lawn can not be found. Even artificial turf is notably absent, perhaps because no one wants to go outside in such horrid weather.

I suppose that I will never know until I go there.

September 11 Remembrance Garden, Winslow, Arizona

P71118The main complaint about this Remembrance Garden is that there is no garden. Two steel girders from the destroyed World Trade Center stand vertically on pedestals within a concrete slab shaped like the site of the World Trade Center. The pedestals are set within squares of stones that correspond to the outlines and locations of the of the World Trade Center Twin Towers #1 and #2 within the World Trade Center Site. The outlines and locations of the other buildings of the World Trade Center are designated by darker concrete within the slab. There is no real synthetic landscape. Only a few ash, cottonwoods, pines and junipers are scattered about.

This might be the most perfect landscape I have ever seen.

Please don’t get me wrong. I appreciate good landscapes that do what they were designed to do. Most of the prettiest are designed to make spaces more appealing. They make our homes more homey. They make our offices more comfortable. They shade streets and parks to make them cooler during warm weather. Whatever landscapes are designed to do, they should do it well. That is precisely what is demonstrated so perfectly by the landscape, or lack of synthetic landscape, at the September 11 Remembrance Garden of Winslow in Arizona.

This is not a comfortable space. It is not intended to be. A bit of shade might be nice during the hot summers in Winslow, but would detract from what this space is set aside for. The starkness and harshness are important here. There is nothing to distract, nothing to obscure, nothing to interfere with what the Remembrance Garden is designed for.

The Remembrance Garden is located outside of the eastern edge of town and on the western edge of the Painted Desert. It might have benefited from more of a synthetic landscape if it had been located in town. A few trees and evergreen shrubbery might have been useful to soften any urban surroundings. Actually, the girders were temporarily located in a lightly landscaped area when they first arrived in Winslow, and then moved to this site a bit later. Despite the complaints of a few insensitive tourists, it is hard to believe that this setting and landscape were not very thoughtfully planned out.


Yuccas (reblogged)


P71022+Yuccas are almost as useful as aloes are for gardening in chaparral or desert climates. I say ‘almost’ because most are not quite as friendly. The leaves are outfitted with nastily sharp tips. It is how they protect themselves from grazing animals in the wild, but it is not such an advantage in home gardens. Some actually have the potential to be dangerous where someone could bump into them. The leaves of Joshua tree can puncture leather. Some types of yucca get so big that they make it difficult to avoid their nasty leaves, even if planted in the background.

That being said, for those of us who do not need to worry about endangering children, dogs or anyone else out in our gardens, yuccas are very distinctive and handsome plants. Their striking foliage radiates outward from dense foliar rosettes. Large spikes of creamy white flowers that bloom in summer or autumn stand above the foliage quite boldly. Some yuccas produce remarkably tall floral spikes. Our Lord’s Candle, Yucca whipplei (Hesperoyucca whipplei), is a terrestrial yucca that sits low to the ground, but produces a huge flower stalk that stands ten feet tall! Modern garden varieties of Adam’s needle, Yucca filamentosa, are variegated.

Of the yuccas that develop sculptural trunks, only a few are available in nurseries. The giant yucca, Yucca elephantipes, is almost too common in mild climates, and unfortunately develops a massively distended trunk that is too big for some of the situations it gets into. Most other trunk forming yuccas that grow slower are uncommon because they are susceptible to rot in landscapes where they get watered through summer.

Except for a few tropical yuccas that are very rare, yuccas are very drought tolerant. Even in desert climates, some yuccas survive on annual rainfall. Others are happier if watered a few times through summer. Giant yucca happens to be a tropical yucca, but surprisingly does not need much water.

Giant yucca is very easy to propagate from cuttings of the big canes. Even big pieces can be cut and stuck as cuttings. However, most of the tree yuccas are difficult to propagate.

Terrestrial yuccas that do not develop trunks are generally easy to propagate by division of pups, although some are difficult to handle. Some terrestrial yuccas actually develop small trunks that creep along the ground, or maybe stand a few feet tall. They can be propagated as cuttings like giant yucca.