Yucca, Tangerine, and Hellebore

Yucca rostrata ‘Blue Velvet’

Yucca linearifolia

giant yucca (Yucca gloriosa)

 

What do a yucca tree, a tangerine tree, and a hellebore have in common?  Not much, really, except that, if you live in the San Fernando Valley, you can grow all three of them in your own backyard.
Yucca tree, tangerine tree, and hellebore are mentioned together here because, within the span of several days, I received correspondence regarding each.  Yuccas are native, primarily, to the American Southwest and Mexico, tangerine tree origins are in Southeast Asia, and hellebore’s habitat is in the Balkans (Southeast Europe).
If you live in the Valley, you don’t have to travel the globe to appreciate the Earth’s botanical diversity.  Right where you live, you can host exotic species from almost anywhere.  We tend to take our blessings for granted and, locally at least, this would include an incredibly favorable climate that supports the growth of a vast spectrum of plants.
“Please write about yucca trees,” Carolyn Mahar emailed from Ventura.   “There are a few of them in my yard. They do well with little care. Please write about the different species, their care, life span and propagation. In Ventura there is a stand of tall yucca trees that are beautiful. They can be seen from the 101 freeway, driving north, on the ocean side of the freeway.”
Well, it’s hard to resist the temptation to write about yucca trees since the most famous of them, the Joshua tree (Yucca brevifolia) bears my name.  To the Mormons who settled in Utah amongst the yuccas in the middle of the 19th century, the tree was simply called “The Joshua.”  Wikipedia claims that this name was given on account of a Biblical story where Joshua “raises his hands up to the sky,” evoked by the skyward branching habit of Joshua trees.  The only problem with this theory is that nowhere in the Bible does Joshua raise his hands to the sky.  It is more likely that since Joshua led the nation of Israel into the Promised Land, and since Utah was considered by the Mormons’ to be their Promised Land, it was easy to make an association between the Biblical figure and the yucca trees that dotted the landscape of the Mormons’ new home.   Incidentally, another name for Joshua tree is yucca palm and it was this appellation for which Palmdale, a habitat for myriad yucca palms, was named.
Yucca trees enjoy a unique and mutually beneficial relationship with a pollinating moth.  The moth transfers yucca pollen grains to stigmas (female flower parts), where the moth lays its eggs.  Yucca moth larvae begin to emerge from these eggs just as yucca seeds begin to develop.  The larvae nourish themselves on the seeds, leaving some of them behind so that another generation of yuccas can grow and nourish future generations of yucca moths.
Yuccas are related to agaves and live under similar conditions except that yuccas are generally more cold tolerant and nearly all yucca species, unlike agaves, do not die after flowering, living for more than 100 years when properly situated.  The yucca range is also transcontinental, with certain species indigenous to the Midwest and Southeast, too.
The most popular yucca in Southern California, although native to Central America, is the giant yucca (Yucca elephantipes).   It grows quickly to a height of up to thirty feet.  Lanceolate leaves are soft and lush green.  In Ventura and coastal areas, giant yucca can take practically full sun but in our interior valleys, it does best in half day sun and will suffer from intense afternoon rays.  Being of Central American origin, it will grow best when given regular water.
Spanish bayonet (Yucca aloifolia) is noted for its imposing vertical inflorescences, reaching up to 2 feet in height this time of year.  As its name suggests, its leaves are sharply pointed so it should not be planted near entrances or walkways.  It’s a slow grower to around 10 feet.  Banana yucca (Yucca baccata) produces interesting fibers that provide frost resistance as well as edible six inch fruits. Yucca linearifolia (to four feet tall) and Yucca rostrata (to ten feet tall) are stunning, slow growing small trees with very thin leaves that develop into massive clumps on the ends of thatched trunks so that, from a distance, they could be mistaken for palm trees.
All the yuccas mentioned in the above paragraph are native to the Southwest or Mexico, are highly drought tolerant, and can grow in full to half day sun.  They demand excellent drainage and make fine architectonic subjects for container gardens.  Local sources for yucca species may be found at worldwideexoticsnursery.com, smgrowers.com, california-cactus-succulents.com, and theodorepayne.org.
As for propagation, take 3-6 inch stem pieces topped with leaves this time of year, detach all but the most upper leaves, lay these stem cuttings on their sides in the shade for a few days, and then insert them in fast draining soil in six inch (1 gallon) containers.  Place in dappled sunlight, water enough to keep soil moist and roots should start to form within a month.  If your yucca produces seeds, you will need to rub them on sandpaper (it’s called scarification) prior to planting in a cactus soil mix at a depth equal to the seeds’ length.  Sprinkle some compost over the top and place in partial sun. Seeds should sprout within two weeks.
RoseMarie Walker, who gardens in Granada Hills, emailed as follows:  “I have a tangerine tree that has produced abundantly since I planted it about 10 years ago. So many each year that I supplied friends and neighbors for several months. All very sweet and seedless. Now this year it is almost barren.  I can quickly count the small number of tangerines that it has even though there were lots of flowers as usual. What has happened?  This past fall I had it trimmed.  Could that be the problem or maybe too much rain or is it infected?”
The fact that you had your usual crop of flowers but very little fruit points to a number of possible explanations.  As you suggest, the heavy rain may have something to do with your small harvest.  The rain would have leached or drained through the soil certain minerals — such as calcium and boron — that play a role in keeping flowers and fruit attached to their stems.  It may also be that after 10 years of heavy fruiting your tree just needs a rest, especially since certain tangerine varieties are known for alternate bearing, which means they tend to produce heavy crops every other year.  Also, as you suggest, it is possible that the rain could have brought on a fungus infection where your blooms were concerned, contaminating them so they fell off before fruit could form.  It would be advisable to fertilize your tangerine tree according to the recommendations found on the bag of specially formulated “citrus food,” which you can find at any nursery or garden center.
The word tangerine, by the way, comes from its association with Tangier, a city located on the northern tip of Morocco at the Straits of Gibraltar, directly across from Spain, where a special mandarin variety — that would become known as tangerine — was cultivated.  In 1842, the first tangerines were shipped to the US from Tangier, arriving in the town of Palatka in northern Florida.  Their popularity quickly grew from there.
Tip of the Week:  Joan Stevens sent the following email:  “Why do I repeatedly read that hellebores don’t grow here?  I live in zone 10A in Pasadena. I think hellebores are lovely and would like to grow some of the beautiful colorful varieties.  In your experience, is it worth it to try?”  Yes, hellebores grow just fine in our area.  I have had a clump of cream colored hellebores growing in a mostly shady location for many years.  This is definitely a seasonal treat, flowering in late winter and early spring, with chalice shaped flowers nodding modestly above blue gray foliage.  Once warm weather sets in, foliage dries up and disappears but the plant reliably returns each winter.  There has been a lot of hellebore hybridization over the past few decades and, as you mention, many flower colors, including yellow, red, violet, and blackish purple are available.  You might have to go mail order to find hellebores since they are virtually absent from the nursery trade in our area but readily accessible through Internet vendors.  Plant them with other perennials suitable for shade such as Japanese anemone, cyclamen and clivia.
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