Tuesday, January 31, 2012

UC Berkeley Botanical Garden: Mexican Collection

Last weekend, I visited the University of California Botanical Garden located on the campus of UC Berkeley to check out their ongoing plant clearance sale. After I had safely stowed my haul in my car, I decided to take a look at the Mexican and Central American collection, skipping my usual haunts, the Southern Africa section and the New World Desert.

The Mexican and Central American collection recreates evergreen cloud forest and pine and oak woodland habitats. Most of it is forested, and lush ferns thrive in moist pockets. I’m not a tree expert, but many rare species of magnolias, pines and spruces are said to grow here. The main attraction for me were the succulents, the majority of which grow in sun-drenched clearings.

Unlike the New World Desert, which looks like a man-made landscape, this section of the Garden has a very naturalistic look. It’s easy to forget that you’re in the Bay Area and not in some remote part of Mexico. The downside, if you can call it that, is that the plants aren’t as “perfect” as they would be in a manicured planting bed. There is leaf litter and tree detritus, and the area has the disheveled look of nature. Some people may find this objectionable, but I actually found it refreshing. Plus, it makes me feel better about all the leaves that are mixed in with my succulents at home.

The very first succulent I spotted was this large Beschorneria albiflora. Like agaves, beschornerias form rosettes but their leaves are soft and unarmed. While most agaves only flower once and then die, beschornerias flower every year. Beschornerias are not very cold-hardy, although the Beschorneria albiflora in our backyard has survived 25°F with no ill effects.

Beschorneria albiflora

Grass trees are always an impressive sight. Australia has its xanthorrhoeas and Mexico has its nolinas. The first one I was simply labeled “ Nolina sp.” but it was beautiful nonetheless.

Grass tree (Nolina species)
Nolina leaves against the sky

Nolina nelsonii, shown in the next photo, forms a perfect head of stiff leaves and eventually a trunk up to 8 ft. tall. At a distance, it looks quite similar to Yucca rostrata (see further down) but its flowers are very different. Nolina nelsonii is hardy to 0°F and deserves to be used more frequently in xeric landscaping schemes.

Yucca faxoniana (left) and Nolina nelsonii (right)

The plant on the left in the photo above is Yucca faxoniana, another supremely architectural species in what has got to be the most underappreciated genus in the succulent world. Just take a look at these magnificent leaves adorned with curly threads. This is a large plant, up to 15 ft. tall. While not as ├╝ber-hardy as some of the other yucca species, it still tolerates temperatures down to 0°F.

Yucca faxoniana

I’ve raved about Yucca rostrata before (1 2 3 4), and I was happy to come across another magnificent specimen in this section of the Garden. (If you’ve been to UCBG, you’ve seen the spectacular Yucca rostrata just outside the main entrance.) I can’t wait for my own specimens to look like that. It might be another 20 years, considering how slowly this species grows.

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Yucca rostrata (background)
and Agave scabra (foreground)

Seen in the photo above and below, Agave scabra is a fairly large species (4-6 ft. across) with gray-green leaves sporting serrated edges. It is abundant in the Chihuahuan desert (northeastern Mexico into south Texas) where it grows at altitudes from 3,600-5,700 ft..

Agave scabra

Agave chiapensis is a medium-sized (2-3 ft. across) species that freely offsets, eventually forming large clusters. As its species name suggests, it is native to Chiapas, Mexico’s southernmost state, and hence fairly intolerant of cold. It will take a few degrees below freezing, but gets damaged below 25°F.

Agave chiapensis

Agave montana grows high in the mountains of northeastern Mexico and is tolerant of cold (10°F), drought and poor soil. It has the potential to grow to 6 ft. across but in cultivation it will most likely stay smaller. It has apple-green leaves (actually quite similar to Agave chiapensis above) with large teeth and a pronounced terminal spine. I love this agave and don’t know why it isn’t more popular. (A tissue-cultured selection called ‘Baccarat’ is sold in specialty nurseries.)

Agave montana

Agave filifera (seen on the left in the next photo) is the archetypical thread-leaf agave. It forms rosettes to 2 ft. across and can easily be recognized by the many curly threads along the leaf margins. I have a subspecies called Agave filifera ssp. schidigera, which I bought several years ago at UCBS’s Landscape Cacti and Succulent Nursery (open to the public for plant sales every Thursday from 10:30am to 1:00pm). It looks just like Agave filifera but has slightly wider leaves.

Agave filifera (left) and Agave montana (right)

Agave striata is widely available in nurseries, even in box-store garden centers. Strangely enough, I do not have this species in my collection, but will remedy that soon. It’s a small species, usually no more than a foot across, but it suckers prolifically, forming large colonies. It is one of the few agaves that are polycarpic, i.e. they do not die after flowering. It tolerates temperatures in the mid-20s.

Hedgehog agave (Agave striata)

While many agave species are unique and don’t interbreed, others do, resulting in hybrids that are difficult to place taxonomically. Several at UCBG were labeled “Agave sp.,” meaning that even the experts don’t really know what species they are. As is the case with dogs, mongrels are often surprisingly beautiful, and these agaves are no exception.

Unidentified agave species or hybrid
Giant agave flower stalk
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Unidentified agave in a sea of penstemon

In one particularly sunny corner of the Mexican Collection, I came across two species of Graptopetalum, a prolifically offsetting groundcover succulent. Graptopetalum goldii is a new species to me; I love how its bright green leaves contrast with the purplish echeveria rosettes next to it.

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Unidentified echeveria species (left) and Graptopetalum goldii (right)

Graptopetalum amethystinum, aptly named “lavender pebbles” in common parlance, looks quite alien to gardeners unaccustomed to succulents. Last year, I bought a specimen labeled Graptopetalum amethystinum, and it’s turned into a large solitary rosette. I wish it would produce some babies so I have some to plant in other places.

Graptopetalum amethystinum

After photographing many of the cycads at UCBG last December, I’ve been on a cycad kick. I ordered a few small ones and have been reading up on these living fossils. I was ecstatic when I encountered quite a few dioons growing in the Mexican Collection.

Dioon is a Mexican cycad genus that does particularly well in our climate. Dioon edule is the most common species. It tolerates cold (down to the mid-20s), heat, drought and poor soil with aplomb and, next to the sago palm (Cycas revoluta), it’s one of the cheapest cycads to buy. There are several subspecies, some with significantly bluer leaves, but the ones at UCBG looked pretty much like the species.

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Yucca faxoniana and Dioon edule
Dioon edule
Dioon edule cone
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Dioon edule (background) and Muhlenbergia dumia (foreground)
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Dioon edule (foreground) and Muhlenbergia dumia (background)

I’m so enamored with Dioon edule that I just bought three seedlings on eBay. Stay tuned for a separate post.

NOTE: Most of the photos in this post were taken either in full sun or in dappled light. I would have preferred a nice overcast day but the weather wasn’t on my side. I plan on going back in the summer when, oddly enough, the weather in the Bay Area is often overcast.

Sunday, January 29, 2012

UC Berkeley Botanical Garden winter sale

Last week I received notice that the University of California Botanical Garden at Berkeley (UCBG) is having a “winter overstock sale” until February 5, 2012. Considering that plant sales are to plant aficionados what a red cape is to a bull, I had no choice but to go.

The weather was perfect on Saturday and the views from the top of the UC Berkeley campus just stunning. The Botanical Garden is located a little lower than the spot where the photo below was taken and it doesn’t offer the same sweeping views, but you are able to catch glimpses of the Bay and San Francisco beyond from a few higher areas.

View from the top of the UC Berkeley campus

Before swooping down on the plant tables, I decided to take a few photos to give you an idea of what was available. I was mainly interested in succulents, and two tables were dedicated to succulents. The other tables were perennials and shrubs. I’m sure there are some unique plants to be found there, but I’m not enough of an expert to know for sure. There were lots of California natives, reflecting a rising trend to landscape with plants from our very own state.

Winter clearance sale tables
Winter clearance sale tables

Prices were excellent, ranging from $2 for 4” plants to $8+ for 1 gallons and $15+ for 3-5 gallons. The octopus agaves (Agave vilmoriniana) in the lower right, for example, were $5. That’s a phenomenal price. The Agave americana ‘Mediopicta alba’ on the right were $8 for a 1-gallon plant. UCBG members receive the regular 10% discount off these sale prices.

Aloes and yuccas

In addition to the sale tables, the plant deck had the usual selection of plants: larger succulents prominently displayed on the steps to the gift shop…

Regularly priced succulents on steps of plant deck

…and smaller succulents, perennials, shrubs and trees from all over the world outside and behind the gift shop. Where else can you find three araucaria species (including the monkey puzzle tree), rare South African bulbs (like Haemanthus), carnivorous plants and other curiosities in one place? Sure, a retail nursery has many more plants, but the selection here is quirky and interesting.

More plant tables just outside the gift shop

After initially grabbing a whole bunch of stuff, I decided to err on the side of reason and limit myself to the plants I really wanted. After all, it’s getting more and more difficult to figure out what to do with the plants I buy.

Here’s what I ended up getting. Perhaps not the most exciting selection at first glance, but each plant “spoke” to me on some level.

The first is Crassula lycopodioides. It’s now considered synonymous with Crassula muscosa although it does not have that species’ tight “watch chain” pattern. I was attracted to this plant because I’m looking for interesting groundcover plants capable of filling spaces between larger plants in our various succulent beds.


Crassula lycopodioides


Crassula lycopodioides and Cycas revoluta

The second plant was the ‘Gollum’ cultivar of Crassula ovata. It is easy to recognize by its almost tubular leaves, some ending in what looks like a suction cup. It’s much smaller than the regular jade plant (Crassula ovata) but its overall habit is very similar. ‘Gollum’ is not particularly rare, but I didn’t have one in my collection yet.

Crassula ovata ‘Gollum’

Crassula ovata ‘Gollum’

Speaking of jade plants, my biggest purchase actually was a jade plant. Unlike our specimens, this one has much smaller and rounder leaves, with a much more yellow coloration and a pronounced red margin. It’s clearly different from the species, although the tag didn’t specify a particular cultivar. I’m thinking it might be ‘Hummel’s Sunset’ but I can’t be sure. If anybody has any insight, please leave a comment.

Jade plant (Crassula ovata) with small, round leaves

Crassula ovata stems

Crassula ovata stems

The final plant I bought is a unique hybrid of Agave ornithobroma with—well, that is the question. Some agaves are notoriously promiscuous, and an Agave ornithobroma blooming at UCBG got pollinated by another blooming agave nearby. This is one of the offspring of this botanical one-night stand. Closely related to Agave geminiflora, Agave ornithobroma usually has many thin, cylindrical leaves (see here). This hybrid has somewhat wider, keeled leaves. Hopefully over time it will become easier to figure out who the dad might have been.

Agave aff. ornithobroma

After paying for my plant purchases, I did some exploring in the Mexico section of the garden. I found a treasure trove of agaves, yuccas, beschornerias, and dioons growing in naturalistic conditions. Click here to read that post.

Saturday, January 28, 2012

Liberating succulents from smothering grasses

A few years ago—before I started this blog, which is why I have trouble remembering—I bought a six-pack of blue fescue (Festuca glauca ‘Elijah Blue’) and planted them in the two small succulent beds in the back yard. At that time, the succulents were small and there seemed to be a lot of space between them that begged to be filled.

Fast forward to 2012. The blue fescue plugs are now clumps 12-18" across and, while attractive in their own right, are covering some of the succulents. After the recent rains, now is a great time for transplanting, and that’s exactly what I did.

Succulent bed 1

In the first set of photos, you’ll see the succulent bed in the northeast corner of the backyard. It is shaded by a row of four bay trees planted against the fence so it only receives about 2-3 hours of direct sunlight in the summer, virtually none in the winter. This is not a logical spot for succulents, but to my surprise they’ve done well—except the fescues and the variegated feather reed grass (Calamagrostis × acutiflora 'Eldorado') have done even better. Time for the grasses to go!

Small succulent bed in the northeast corner of the backyard
”Before” photo with fescues and variegated feather reed grass
(Calamagrostis × acutiflora 'Eldorado')

Fescues dominating the foreground, hiding several aloes, a dyckia, an agave and a yucca

The difference after removal of the grasses is astounding. You can see plants that were all but impossible to see before.

“After” photo

Small dyckia species with many offsets

This Agave montana ‘Baccarat’ was all but invisible. It’s easily doubled in size (it was planted from a 4" pot) but due to a lack of direct sunlight, its form is much more open than it would otherwise be. Still, beautiful coloration and nice scalloped edges.

Agave montana ‘Baccarat’

For comparison, here are a couple of mature specimens of Agave montana ‘Baccarat’ (photo taken from the website of Yucca Do, the nursery that introduced ‘Baccarat’ to tissue culture). If my smallish plant ends up looking like that, I’ll be very pleased.

Mature Agave montana ‘Baccarat’
Photo: Yucca Do Nursery

Here’s another agave that was partially covered: Agave funkiana ‘Blue Haze’. From the photos I’ve seen, it has an open habit like that even in full sun. More evidence that many succulents are able to handle shade remarkably well.

Agave funkiana ‘Blue Haze’

What did I do with the fescues I pulled up? I planted them 15 feet away in the same general area, just behind the bamboo fence. Here you can see two of them. The others (from the succulent bed described below) are to the right.

Relocated Festuca glauca ‘Elijah Blue’

Succulent bed 2

In the same corner of the backyard as our Asian-inspired woodland garden there is a narrow (12” deep) planting strip that in the past proved challenging to use. A few years ago I planted a combination of aloes and agaves, and they’ve thrived in this mostly shady spot. But, as was the case with the bed above, so have the fescues.

“Before” photo with fescues completely hiding Agave parryi ‘Truncata’

This Agave parryi ‘Truncata’ was almost impossible to spot between the two clumps of fescue. Not surprisingly, it’s a bit etiolated but I’m hoping that it will tighten up over time and eventually form its trademark artichoke look. (This area might be too shady, resulting in a looser habit.)

Uncovered Agave parryi ‘Truncata’

The same thing happened to this Agave lophantha ‘Quadricolor’.

Fescue hiding an Agave lophantha ‘Quadricolor’

I had no idea it had grown to such a nice size—it was a pup I took off the mother plant next to our front door.

Uncovered Agave lophantha ‘Quadricolor’

While not obscured by the fescues, this Aloe cameronii × maculata hybrid has positively exploded. I love its long, strappy leaves and its rich green color.

Aloe cameronii × maculata

Here are two more aloes at the head of this narrow planting strip. They have thrived as well. Aloe nobilis, in the foreground, was a 1-gallon plant on special at Target, and Aloe glauca came to me as a cutting. I love how their different colors complement each other.

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BACK: Aloe glauca
FRONT: Aloe nobilis

Aloe glauca

The next aloe, Aloe microstigma, is at the other end of this succulent bed. It think it’s one of the nicest looking smaller aloes. It used to be relatively hard to find but its availability has improved in recent years. I even saw one at Home Depot last year, and there’s nothing more mainstream than that.

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Aloe microstigma

And finally here is a stitched panorama of the entire bed, post fescue removal.

Backyard succulent bed outside the dining room