Friday, March 2, 2012

Yucca rostrata

As much as I love agaves, the beaked yucca (Yucca rostrata) is my favorite succulent for the landscape. Native to western Texas and northern Mexico, it grows on rocky slopes and ridges and tolerates harsh climatic extremes both in the summer and in the winter. It is reputed to take temperatures below 0°F, making it one of the hardiest of all yuccas.

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Yucca rostrata at The Living Desert

Over time—decades, really, since it’s a very slow grower—it forms a trunk to 12 ft. tall. Last year I saw specimens maybe 9 ft. tall at The Living Desert in Palm Desert, CA, and they were impressive with their circular heads of stiff gray-green leaves. These plants were left in their natural state, i.e. the old leaves were left on to form a skirt much like you would see on a palm tree. In a garden setting, the dried leaves are often trimmed, creating a more manicured effect:

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Yucca rostrata at Poot’s Cactus Nursery in Ripon, CA

Over the last few years, I’ve accumulated five Yucca rostrata, ranging from plants in 1-pint containers to the 2-ft. specimen I bought at Poot’s Cactus Nursery in Ripon, CA last November. Four or five years ago, Yucca rostrata was all but impossible to find locally. Now I see it occasionally in independent nurseries. While small plants (typically round 1-pint containers) cost the same as other perennials, about $6, the price of older specimens that have begun to form a trunk quickly climbs into the hundreds of dollars.

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My collection of Yucca rostrata

Yucca rostrata seems to be a fairly variable species, especially in terms of leaf color. The standard color is grayish green:

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A tissue-cultured selection called ‘Sapphire Blue’ is supposed to be particularly blue, but mine (seen two photos above in the terracotta pot on the left) is the same grayish green as the regular form. However, my specimen from Poot’s has a very strong powdery blue cast:

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My own Yucca rostrata, purchased at Poot’s Cactus Nursery in Ripon, CA
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Close up of the same plant

Above I said I have five Yucca rostrata. However, if you look at the photos closely, you’ll see six plants. The sixth, seen on the right in the next photo, is Yucca linearifolia. Discovered in northern Mexico in the 1980s, it was initially thought to be a subspecies of Yucca rostrata. Since then, some taxonomists have promoted it to species status. Since seed had been virtually impossible to obtain, it was put into tissue culture and is slowly becoming more available.

The leaves of Yucca linearifolia are narrower, less stiff, and greener in color than Yucca rostrata. I can definitely see the difference in my own plants, but in older specimen that difference seems to less pronounced: Looking at these photos, I would have thought that these are Yucca rostrata instead of Yucca linearifolia. In practical terms, these differences are irrelevant because both species are supremely architectural and equally gardenworthy.

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Yucca rostrata (left) and Yucca linearifolia (right)

Below are some additional photos of Yucca rostrata from various places in Northern California. Since it’s so cold hardy, it has the potential to grace gardens in much of the U.S. and Europe.

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Cactus Jungle Nursery, Berkeley, CA (left), Poot’s Cactus Nursery, Ripon, CA (right)

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University of California Botanical Garden, Berkeley, CA

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University of California Botanical Garden, Berkeley, CA

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Ruth Bancroft Garden, Walnut Creek, CA

9 comments:

  1. This plant is very high on my wish list this year. Just beautiful! I'm glad you showed the trimmed trunks, as I usually see the shaggy look when researching this plant, and I wasn't too fond of it.

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    1. The shaggy look is an acquired taste, much like it is with palm trees. I happen to like it but I also like the trimmed look, which, I will admit, it better suited to contemporary gardens. I don't understand why nurseries in your area don't stock Y. rostrata. It's certainly hardy enough for your climate.

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  2. I had the opposite reaction that Alan did. I loved the look in the first couple of photos.

    I've got 7 Y. rostrata ranging from the grand Sammy with his approx 3 ft trunk (from Cistus) to a tiny 4" container bought for $4 at the HPSO plant sale last fall. I, like you, find this to be one of the best architectural desert looking plants out there. So hardy! And beautiful at every stage. I do have one small Y. linearifolia bought at the same time a Y. rostrata of the same size was purchased. The Y. linearifolia is much much slower growing. Will you be planting your trunked Y. rostrata in the ground?

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    1. I like both the natural and trimmed look. Since my larger specimen has a trimmed trunk already, I'll likely keep it that way. Yes, it will go in the ground in the succulent bed by our front door. I think it will grow faster if its roots have room to run.

      I also think Y. linearifolia is slower growing but it's all relative with these plants :-).

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  3. Uh oh looks like I need a couple of those! Definitely want a big one! Need to go to Poots! How much are the big ones!

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    1. Let's do a road trip to Poot's! The big Yucca rostrata I got was $42. Very reasonable considering that in the Bay Area you'd pay over $100.

      Poot's also had Yucca thompsoniana, essentially similar but branching. I'll get one of those the next time I go.

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  4. I agree with you, such stunning plants, can't get enough of them myself!! It seems it's more difficult and expensive for you guys to get a trunked specimen than in here, odd how that worked out. Linearifolia is said to be much easier to cultivate than rostrata, I found the same but rostrata is a stunner!

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    1. I think the availability of Yucca rostrata is much better in Southern California and Arizona. But since it's so slow-growing, it's expensive to buy a larger specimen. Where are the plants grown that you guys have access to?

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  5. We grow Yucca Rotrata here in deep South Texas.

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