Wednesday, December 28, 2011

University of California Botanical Garden, part 1

I took advantage of the break between Christmas and New Year to visit the University of California Botanical Garden (UCBG) at Berkeley, about an hour from Davis. As expected, there were few visitors, which made for a leisurely pace and allowed me to take as many photos as I wanted, even in places that are often crowded (like the small Tropical House). Unfortunately, what was forecast to be an overcast day (good for photography) turned out to be sunny, so taking photographs in forested areas was all but impossible.

UCBG covers 30+ acres and is subdivided into nine major geographic regions (Mediterranean, Southern Africa, New World Desert, Mexico/Central America, South America, Eastern North America, California, Asia, Australasia) and several special collections (like Orchid, Fern & Carnivorous Plant House, Arid House, Tropical House, Cycad & Palm Garden, Garden of Old Roses, Crops of the World Garden, Herb Garden, Chinese Medicinal Herb Garden).

I didn’t walk through all areas because some of them aren’t that interesting to me and others aren’t that attractive in the winter. It should come as no surprise that I spent most of my time looking at cacti and succulents. But I also visited the Tropical House, which was much more bearable than in the summer, and enjoyed the coolness of the Cycad & Palm Garden. This post, therefore, doesn’t claim to give you a systematic overview of UCBG. Instead, it’s a somewhat random photo essay of plants that caught my eye.

I love the entrance to UCBG because it features a large specimen of one my favorite plants, the beaked yucca (Yucca rostrata). Peaking over the wall behind it and looking like a feather duster on a long pole is a culm of Mexican weeping bamboo (Otatea acuminata ‘Aztecorum’)…

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The steely blue rosette on the left is Yucca rostrata

…which is planted on the other side of the wall. If I had to make a choice, I’d probably pick Otatea acuminata ‘Aztecorum’ as my favorite bamboo. I love its long slender leaves that move in the slightest breeze and impart an irresistibly tropical flair to any garden space.

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Mexican weeping bamboo (Otatea acuminata ‘Aztecorum’)
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Mexican weeping bamboo (Otatea acuminata ‘Aztecorum’)

The Entrance Plaza is one of my favorite spots in the entire garden because there are so many “spiky plants” that are both beautiful and rare, at least in Northern California. Just take a look at this combination of an Alexandria cycad from the coastal sand dunes of the Eastern Cape in South Africa (Encephalartos arenarius on the left) and a grass tree from Australia (Xanthorrhoea glauca on the right).

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LEFT: Encephalartos arenarius
RIGHT: Xanthorrhoea glauca

The next photo shows another Old-World-meets-New-World combination: Nelson’s bear grass from northern and northeastern Mexico (Nolina nelsonii on the left) and Encephalartos eugene-maraisii from Transvaal province in South Africa (on the right).

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LEFT (in pot): Nolina nelsonii
RIGHT: Encephalartos eugene-maraisii

Speaking of cycads, UCBG has an extensive collection of these ancient cone-bearing plants. I didn’t see a sago palm (Cycas revoluta), far and away the most common cycad in cultivation, but I saw representatives of the genera Cycas, Encephalartos, Macrozamia, and Dioon. I’m sure they have other genera as well, but not all cycads are distinctive enough to stand out—some look like young palms with plain green fronds.

The following cycads did stand out, and I would be thrilled to have any of them in my garden. Just to give you an idea of how valuable these plants are: At A&A Cycads, one of the leading cycad nurseries in the U.S., an Encephalartos arenarius specimen with a 10 inch caudex (base) is $2,375. The plants below are bigger than that.

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Two Encephalartos arenarius,
native to the coastal sand dunes of the Eastern Cape Province in South Africa
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Encephalartos trispinosus, also native to South Africa’s Eastern Cape province
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Another Encephalartos trispinosus
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Close-up of Encephalartos trispinosus leaves
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Encephalartos horridus × longifolius with a particularly large caudex.
This one is right next to the Conference Center.
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Macrozamia moorei, native to Queensland, Australia

But let’s go back to the Entrance Plaza. On the left is the Garden Shop which sells not only books, jewelry and all the other stuff you’d expect from a gift shop at a botanical garden, but also a surprisingly large selection of plants. Below is just a tiny portion of what’s available. They sell cacti and succulents, California natives, perennials, trees and shrubs, and even rare collector’s plants like monkey puzzle tree seedlings. The prices are very fair, and UCBG members get a 10% discount.

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Some of the plants available for sale on the plant deck outside the Garden Shop. I was particularly surprised to see Fargesia, a clumping bamboo from the mountains of China (species not identified).

Straight ahead from the entrance is the Arid House, a temperature-controlled structure housing tender succulents, cacti and caudiciforms (“fat plants”) from the Old and the New World.

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Looking towards the Arid House
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Yucca rostrata and Agave americana ‘Mediopicta alba’ outside the Arid House
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Yucca rostrata
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Yucca rostrata

These three Dudleya brittonii are planted outside the Arid House. They are truly perfect specimens of this rare succulent from Baja California. The rosette is covered with a white “wax” that comes off very easily, hence the sign not to touch the plants. According to Wikipedia, the wax on Dudleya brittonii has the highest measured ultraviolet reflectivity of any plant.

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Dudleya brittonii
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Dudleya brittonii
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Dudleya brittonii

Dudleya pulverulenta, shown in the next photo, is closely related to Dudleya brittonii and grows in coastal and inland mountains. It is challenging in cultivation, at least to me; I bought one from Annie’s Annuals this summer and planted it in the succulent bed next to our front door. Within the space of two weeks, it died in front of my eyes. I think our hot summer sun was too much. I will try another one next year and keep it shaded.

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Dudleya pulverulenta

Now let’s take a look at a few plants inside the Arid House. There are literally hundreds, if not thousands, of potted succulents, all cheek by jowl. Many of them are rare and of interest only to conservationists and collectors, not necessarily beautiful to look at. But the following caught my eye.

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Browningia hertlingiana, a columnar cactus from Peru with amazingly blue coloration
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Euphorbia horrida (possibly cultivar ‘Snowflake’?) from South Africa, not a cactus at all but with a very similar look and growth form
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Desert rose (Adenium obesum), dormant for the winter
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Elephant’s foot (Dioscorea elephantipes), a caudiciform from South Africa, also dormant. The stalk remnant on the top is from the annual vine that emerges in the spring and can grow to considerable length (12 ft. and longer).
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Socotran fig (Dorstenia gigas), a rare pachycaul tree from the island of Socotra. I bought a small seedling at a UC Davis Arboretum plant sale and it’s dormant for the winter, unlike this specimen.
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Tylecodon reticulatus, a winter-growing “fat plant” from South Africa (where else)

The strangest plant in the Arid House is definitely Welwitschia mirabilis, considered a living fossil. It is found only in the Namib Desert of Namibia and Angola where it grows in incredible hostile conditions. Although age is difficult to assess, individual plants are assumed to live over 1,000 years. In a 2009 competition by British newspaper Daily Telegraph to find the “World’s Ugliest Plant,” Welwitschia mirabilis came in fourth. The specimen at the UCBG is actually a real beauty compared to plants in the wild (be sure to check out this blog post).

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Welwitschia mirabilis
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Welwitschia mirabilis

In the South Africa section just outside the Arid House, I came across a plant that reminded me a little of Welwitschia mirabilis. It’s a bulb called Boophone haemanthoides. The bulb can grow to a diameter of 8 inches or more and is mostly exposed, much like an amaryllis (to which Boophone is related). Check this page for much better photos. I actually wouldn’t mind having this plant in my garden!

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Boophone haemanthoides

My favorite aloe of all is the fan aloe (Aloe plicatilis), and UCBG has a particularly stunning specimen. I dream of having one like that! My own Aloe plicatilis does have a trunk now and it bloomed for the first time last year, but it’ll be years before it’s even half that large.

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Aloe plicatilis
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Aloe plicatilis

I had expected the winter-blooming aloes to be in full flower, but it looks like many of them still have weeks to go. Here is an emerging flower stalk on an unidentified aloe.

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Emerging flower on unidentified aloe

This clump of Aloe pluridens, on the other hand, was in full flower, as were many Aloe arborescens I saw around Berkeley.

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Aloe pluridens

One of the biggest surprise of this visit was coming across two oxalis from South Africa that are actually ornamental and garden-worthy. As you may remember, common yellow oxalis (wood sorrel) is my #1 enemy; it might quite possibly be the most invasive, obnoxious and hardest to kill weed in existence. In contrast, these two oxalis are apparently non-invasive. I must say I am tempted to add them to my succulent bed where they would make a great groundcover.

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Oxalis hirta, available for purchase at Annie’s Annuals
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Oxalis purpurea ‘Alba’, “not in the least bit invasive” according to this article

Click here to go to part 2 of this post. We’ll visit the New World Desert, the Tropical House, and the fantastic Tasmanian tree ferns.

Wordless Wednesday

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Tuesday, December 27, 2011

Manzanitas in the naturalistic landscape

In far Northern California where my parents-in-law live, manzanitas (genus Arctostaphylos) are among the most widespread native shrubs. According to Wikipedia, manzanitas (approximately 60 different species) are found from British Columbia, Canada all the way down to northern and central Mexico. There are ground-hugging species barely a foot tall to small trees 6 ft. or more in height. All except one species are evergreen, and they share small urn-shaped flowers in shades or white and pink, and fruit that look like tiny apples (“manzanita” means “small apple” in Spanish).

Greenleaf manzanita (Arctostaphylos patula) flower
Photo source: Wikimedia Commons

Greenleaf manzanita (Arctostaphylos patula) fruit
Photo source: © 2009 Keir Morse, Encyclopedia of Life

The dominant manzanita species in Mount Shasta is greenleaf manzanita (Arctostaphylos patula). It is native to the coniferous forests of the Western U.S. and grows at moderate to high elevations (the town of Mount Shasta is at 3,600 ft.).

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Greenleaf manzanita (Arctostaphylos patula) with Mount Shasta (14,179 ft.) in the background

Its typical form is a shrub with multiple branches, up to 6 ft. in height, but properly pruned it can be trained into a single-trunked tree.

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Arctostaphylos patula in naturalistic landscape

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Beautiful specimen of Arctostaphylos patula

As its common name suggests, its leaves are a rich apple-green, appearing yellow when backlit.

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Arctostaphylos patula leaves, backlit by the winter sun

The most striking feature of any manzanita is its reddish bark, typically smooth but sometimes peeling in a fashion reminiscent of the madrones, especially the Pacific madrone (Arbutus menziesii) endemic to the coastal ranges from British Columbia down to Central California.

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The contorted branches with their rich coloration are eye-catching visual elements that make manzanita a standout in the landscape.

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Living and dead wood is frequently found on the same shrub. While this can make the plant look messy (as in the next photo), it can also be an advantage if you do some judicious pruning in order to create a natural sculpture.

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Even dead, manzanitas still look good. I would love to have the twisted stump in the next photo in our garden. It would look great placed in front of a clump of bamboo, or surrounded by potted succulents.

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Manzanitas grow best in full sun or light shade. They prefer slightly acidic, fast-draining soil that isn’t particularly rich. They are very drought-tolerant once established; in fact, they prefer to be dry in the summer and should be planted away from sprinklers.

In addition to the naturally occurring species, a number of hybrids and cultivars have been developed specifically for landscaping use. Here is an extensive list, subdivided into manzanitas for Northern, Central and Southern California.

For example, Arctostaphylos densiflora ‘Howard McMinn’ is one the 100 All-Stars selected by the UC Davis Arboretum for their toughness and reliability in our climate. It is sold in many nurseries in the Sacramento area and at UC Davis Arboretum plant sales.

A word of caution: Manzanita wood is highly flammable and manzanitas are considered a fire hazard in some areas. Do not plant them in the immediate vicinity of any structures. However, if you have a larger property and prefer landscaping with native plants, a well-sited grouping of manzanitas will be an eye catcher.