Yucca hybrids and selected cultivars.



Natural occurring Yucca hybrids:
"Wild" Yuccas interbreeds with cultivated Yucca:
Man made Yucca hybrids:
How to pollinate Yucca flowers by hand:
Some of the hybrids that I grow here in Northern Denmark:
Hybrids from gardens, not man made:
List of man made Yuccas in the late 20th. Century and in the early  21st. Century:
Variegated Yuccas.:
List of Yucca hybrids in the "Jensen collection" 2009 (new page)


 


Beautiful Yucca hybrid of unknown origin in Mr. Kristensen's garden
Photo Benny Møller Jensen Copyright © 2003

There are two kinds of hybrids, those that have been made by gardeners and nursery men, and those that has been made in the nature, by "accident".

I suspect that most any species of Yucca can hybridize with one another, as long as the flowers are open at the same time (or, if one saves the pollen). The exceptions would seem to be Yucca brevifolia and Yucca whipplei, of which there never has been any records of hybrids.

According to David J. Ferguson is some species of Yucca self sterile and others are self fertile. He have gotten good fruit when self pollinating Yucca pallida, Yucca rupicola, Yucca thompsoniana and Yucca aloifolia.  He has not been able to get fruits on anything related to the Yucca glauca complex (Yucca glauca, Yucca elata and kind), when they were tried to be self pollinated!.If you have been able to selfpollinate any of your Yuccas, would I very much like to hear about it.



Yucca hybrids in nature:

Yucca plants do interbreed in nature, and many species can be responsible in this phenomenon.

Yucca pallida X Yucca constricta?
Yucca pallida X Yucca constricta?
Photo by Bobby Crabb, Texas ©2001

The following hybrids should occur in habitat:

Yucca aloifolia X filamentosa [= gloriosa?]
Yucca mesae-verdae (angustissima x baileyi) Found in Utah by Fritz Hochstätter (fh 1184.52)
Yucca angustissima x elata subsp. utahensis. Found in Utah by Fritz Hochstätter (fh 1187.32).
Yucca baccata x glauca, northeastern New Mexico’s San Miguel Co. This hybrid were discovered by David Salman, the owner and founder of High Country Gardens New Mexico.
Yucca baccata X schidigera.
Yucca baccata X torreyi.
Yucca baccata X faxoniana.
Yucca elata X baccata.
Yucca elata X rostrata.
Yucca elata X torreyi.
Yucca faxoniana X torreyi.
Yucca faxoniana X elata.
Yucca faxoniana [carnerosana] X filifera.
Yucca faxoniana [carnerosana] X decipiens.
Yucca glauca X baccataCan be found in the Santa Fe area New Mexico, a special feature about those hybrids is that they often has as short trunk up to 100 cm tall, which Yucca glauca and Yucca baccata doesn't have!
Yucca glauca X
In some areas like those around Santa Fe, New Mexico it's difficult to see if a plant is a Yucca glauca or if it has "blood" from Yucca glauca. In this area you can find plants that looks like Yucca baileyi, Yucca baileyi ssp. intermedia, and Yucca glauca (and these could all grow from seed from the same fruit). According to Dave J. Ferguson aren't these as variable in appearance as are plants from many other areas, but the pistil and fruits are rather variable in size, shape, and coloring. Probably best to call them "intermedia" since this is basically a name for varied intermediate populations where Yucca baileyi, Yucca glauca, Yucca elata, and Yucca angustissima blend anyway.
Yucca harrimaniae x baccata, west of Coyote, New Mexico (Lz2007).
Yucca linearifolia (blue form) x Yucca torreyi, this hybrid should grow in the Galeana region Mexico.
Yucca pallida X constricta?
Yucca pallida X arkansana = Yucca necopina?
Yucca schidigera X valida.
Yucca torreyi X rostrata.
Yucca torreyi X thompsoniana.
Yucca torreyi X rigida.
Yucca torreyi X linearifolia.

Yucca xpollyjeaniae (harrimaniae x glauca), Central Colorado 2350-2700m. Hochstätter supplement seedlist July 2010.
Yucca xfeeanoukiae (harrimaniae x harrimaniae ssp. gilbertiana), Northern Utah 1900-2000m. Hochstätter supplement seedlist July 2010.
Yucca xquinnarjenii (baileyi x baileyi ssp. intermedia), Northern New Mexico 1900-2000m. Hochstätter supplement seedlist July 2010.
Yucca xkeithii (elata x constricta), Central Texas. Hochstätter supplement seedlist July 2010.
Yucca xbaccatissima (baccata x angustissima?) fh 1188.67  Hochstätter supplement seedlist July 2010.
Yucca xintermediate (arkansana x campestris), Texas,  Hochstätter supplement seedlist July 2010.
Yucca xglaucissima (glauca x angustissima), New Mexico,  Hochstätter supplement seedlist July 2010..
Yucca xconsana (constricta x arkansana), Texas,  Hochstätter supplement seedlist July 2010.
Yucca xbaylissima (baileyi x angustissima), Utah,  Hochstätter supplement seedlist July 2010.
Yucca xoklahomensis (glauca ssp. stricta x arkansana), Oklahoma,  Hochstätter supplement seedlist July 2010.
Yucca bacsoniana (baccata x thompsoniana) Hochstätter 2008.

According to WEBBER many of the populations of Yuccas are intermediates between the so called "species" of Yucca in the glauca/elata and the rupicola/rostrata groups. If you count these, then perhaps half of all Yucca plants are "hybrids"!?

Yucca recurvifolia is probably Yucca aloifolia [or gloriosa] X Yucca flaccida, but this needs to be proven.

Ref:
FERGUSON, Dave J., 2000, in an email to the discussion group HARDYCACTI_ETC, subject: Yucca hybrid, Thu, 12 Oct 2000 09:02:04 -0700 (PDT)

WEBBER, 1953; Yuccas of the Southwest
                          Agriculture Monograph No. 17, U.S. Department of Agriculture, USA.



"Wild" Yuccas interbreeds with cultivated Yucca:

This is another kind of hybrids.

Yucca faxoniana X Yucca glauca [or "intermedia"], which Mesa Garden used to sell. Was from a large cluster of plants in a median strip in Albuquerque, new Mexico. Since Yucca glauca and Yucca faxoniana never grow together in habitat, this hybrid had to have happened in cultivation, probably right there in that median. Dave Ferguson, have seen a few others of this hybrid, scattered around where Yucca faxoniana is cultivated in the Albuquerque area. But seeds of this hybrid have only been offered once!

--
Mr. Kristensen is enjoying his beautiful row of unusual Yucca hybrids. Seeds were collected in a garden in New Mexico.
Photo Benny Møller Jensen Copyright © 2003

Yucca rupicola x ? (maybe treculeana, torreyi, faxoniana, or maybe rigida?). Seeds harvested at a landscape nursery in New Mexico in 2002 or 2003. A few plants is in cultivation in the private collection of Tim Behan.



Man made hybrids:

The first to make a Yucca hybrid were the German nursery-man Graebener, in 1899 did he make Yucca x karlsruhensis, and a "sport" of this were named Yucca 'Graebeneri'.

The person whom has made most the hybrids were Carl Sprenger. In the years from 1897 to 1907 Carl Sprenger named at least 122 Yucca hybrids! Carl Sprenger's work was continued by Willy Müller.

Willy Müller named the following hybrids:
Yucca 'Sprengerii'
Yucca 'Williamsiana'
Yucca 'Moloniana'

But I don't have any reference on Müller's work, so if any of the readers knows anything please let me know!

Another person were J. B. Deleuil from?, he should had create more than 3000 plants, and some of them were named:

Yucca 'Andreana' (Y. gloriosa plicata x Y. treculeana). This one should have had a "filled" flower with multiple tepals!
Yucca xdracaenoides
Yucca xjuncea
Yucca 'Licida'
Yucca xprocera
Yucca 'Carrierei'
Yucca xensifera
Yucca xgracillima
Yucca 'Messiliensis'
Yucca xstriatula
Yucca 'Deleuili'
Yucca xfloribunda differs from “Sprenger floribunda” in forming large trunks
Yucca xleavigata
Yucca xpilosa
Yucca xsulcata

I'm searching for information about F. N. Rusanov a Professor from the Botanical Institute and Botanical Garden in Tashkent, Republic of Uzbekistan. Until now I have the following:

So far have I found that, from 1945 to 1959 Rusanov did make the following hybrids:

Yucca filamentosa x glauca, this cross gives strong plants which is good for frost and snow.
Yucca elata x glauca No information at the time of writing!
Yucca filamentosa x elata, this cross gives plants with narrow dark green leaves, compact rosette, inflorescense up to 2 meter tall.
Yucca elata x baileyi ssp. intermedia, this cross gives  plants with long narrow leaves, when the plants are mature they have a big rosette of leaves and look very much like a Dasylirion from distance.
Yucca (filamentosa x elata) x pallida
Yucca (filamentosa x elata) x pallida (different seed-donor)
Yucca flaccida x pallida
Yucca (filamentosa x baileyi ssp. intermedia) x pallida

There may be a few more which I have not noticed in the first quick reading thru.  We are still working on the translation (114 pages + 5 other pages from an article about Yucca hybrids). When I know more you will be informed.

Rusanov writes that the hybrids from 1. generation, most often looks like the seed parent. I can not see this in my own hybrids, it depends of the genes of both parents, as I have made the hybrid Yucca filamentosa x glauca, with two different pollen donors, and the outcome is very different. We need to make a lot more than one or two crossings, to get the picture of which genes are the strongest and most dominant, but hopefully can we get a hint on what to expect, as we get more different crossings made worldwide.

You can find information about the hybrids made from 1945 to present day by clicking here.

If you have any information about Yucca hybrids please let me know.

If you are a Yucca breeder, please name your new cultivar according to the International Society for Horticultural Science (ISHS)

Please note following text which is from ISHS's web page about "how to name a new cultivar": "Since 1959, new cultivar epithets must be in a language other than Latin and they must be unique within the so-called denomination class which is usually the genus."


I had tried pollinating Yucca's for many years, but until july 2003 I did not have any luck with that. But in the summer of 2003, my friend Pia Larsen, did find a technique that worked, since our first success, I have made cross pollination of the several species and forms:

Yucca hybrids made in the summer of 2003.
Yucca hybrids made in the summer of 2004.
Yucca hybrids made in the summer of 2008.
Yucca hybrids made in the summer of 2009.
Yucca hybrids made in the summer of 2010.
 


Fruits on Yucca glauca (BMJ #1461) Note that one of the fruits are deform, as if it didn't receive enough pollinium!!
Photo from August 18th 2003.
Copyright ©2003 Benny Moeller Jensen


Hybrids from gardens, not man made:

Yucca 'Albuquerque Mystery I' (recurvifolia x ? (glauca)).
Yucca 'Albuquerque Mystery II' (recurvifolia x ? (glauca)).
Yucca 'Karlson' F:2 = seedling from Yucca 'Karlsruhensis'!
Yucca van Zwet hybrid #57 filamentosa [concava?] x ? self polinated, maybe by ants, Mark van Zwet, The Netherlands.


How to pollinate Yucca flowers by hand:

To get seed pods you  need two different clones of Yucca as they are self sterile! It looks like that we got the best pollination during the time from 19 to 22 in the evening, but then again many of the flowers were pollinated during the morning and in the afternoon, so it's not impossible to pollinate all day long! According to Sprenger it is possible to collect pollen from an early blooming species and save it  in an air tight container for a couple of months and, so it's is possible to pollinate it with an late blooming species! I have not tried it yet, but will collect pollen and try so store it in my freezer for next summer!?!?

List of things you need when you cross pollinate Yuccas:

Small bamboo stick, 5 cm long and less than 1 mm thick. Or use the "stem" of a short grass flower, which is thin enough for this kind of work.
1 black lid from a film canister.
Alcohol to clean stick and lid with.
Paper towel for the alcohol.
3M medical tape (US only)
Labels with a hole.
Bast (raffia) for tying labels to the flower.
Pencil for writing on the labels.
A steady hand + good luck!

How is it done?

The tricky part is to gently collect the pollinium from the anthers, in each flower there are 6 anthers with two polliniums on each (some plants have four!), not all of the pollinium is ripe at the same time, so if you want to pollinate, during the evening and the early morning, you would have to look several times, to be sure the pollen is ready. I collect the pollen with a short (5 cm long) and very thin (less than 1 mm thick) bamboo stick, and collect it in a black lid from a film canister (black makes it easier to see the pollinium). Before starting to collect from a new plant, you need to clean your stick with alcohol, so you don't mix any genes, and don't know who the parents are! It's important to start with collecting pollinium from all the parents you want to pollinate, as the pollinium sits very loose on the anthers, and you will easily shake of the pollinium when you begin to pollinate! When you have collected all the pollinium you need, from those plants you want to try with, you can start pollinating. It's not difficult to pollinate, just pick a pollinium with the thin stick, and gently put in into the stigma of the flower of the "motherplant" with out damaging it (This is the reason why you need a very thin stick) (in USA it might be advisable to but a small piece of  3M medical tape on the stigma, so your local Yucca moth don't pollinate the flower too!). It seems like that freshly opened flowers, are better to pollinate that flowers that are a few days old. Then write a label with the number (all my plants are numbered) and the name of the parents, always with the seed parent first and the pollen parent last. The label is then tied to the pollinated flower with a piece of bast (raffia). In 4-10 days you will know if you have succeeded or failed to pollinate, if failed the flower falls of, and if you have success the fruit slowly starts to point upwards and get a purple tinge. The seeds should be ripe in 6 to 12 weeks, and all you need to do, is to sow the seeds and you might have small seedling of a new your own hybrid next year. Stem less Yuccas normally bloom after 5 to 10 years from seeds, I don't know how many years it takes for those with stems, as none of my plants have ever bloomed!
 
 
1.
The ripe pollen is laying loose on the anthers, but can with a steady hand be collected with a wooden toothpick.
2.
The collected pollen is gently being moved into the lid of an old film canister.
3.
In the lid the pollen can be "rolled" into small balls of pollen, so it is more easy to use later.
4.
A happy pollinator collecting pollen during the darknes of the night, with help of a lamp.
5.
Before you start collecting pollen on a new plant, it is very importaint to clean the hands with alcohol to prevent mix of pollen. If you reues your toothpick, you will have to clean it well too.
6.
With clean hands, you can collect pollen from the next species of Yucca.
7.
The pollen is put into the film canister for future use.
8.
It is importaint to hold the hands very steady as the pollen is easy blown away or lost.
9.
The collected pollen is gently being moved into the lid of an old film canister.
10.
It is time to clean hands again, before you start to pollinate.
11.
Pollen can also be stored and mailed in zip-lock bags, so you can swap pollen with your friends from all around the world.
12.
It is a little more tricky, to use the pollen from the zip-lock bags, but is well worth to try.
13.
A small "ball" of pollen is gently put on the small hole of the stigma.
14.
The of pollen is gently pressed into the small hole of the stigma.
15.
It is importaint that the stigma isn't damaged during the prosess, the small stick need to be a litle smaller in size of the hold in the stigma.
16.
Here you can see that the smalll stick is pressed into the bottom of the stigma.
17.
Yes, I have cleand my hands, before I start again with a new species. Here it is flower of Yucca angustissima ssp. kanabensis.
18.
A small "ball" of pollen is gently put on the small hole of the stigma.
19.
The of pollen is gently pressed into the small hole of the stigma.
20.
Here you can see that the smalll stick is pressed into the bottom of the stigma.
21.
I continue with a new flower.
22. 23. 24.
25.

 

26.
Untill all open flowers are pollinated, and labeled.
27.
Pollinated flowers with labels.
28.
If you are lucky the pollinated flower will produce a fruit, which is ripe in 8 to 14 weeks, depending on species and climate.



Some of the hybrids that I grow here in Northern Denmark:

Yucca 'Albuquerque Mystery I' (recurvifolia x ? (glauca complex)).
Yucca 'Elegantissima' Sprenger hybrid. (Yucca filamentosa var. major X gloriosa)
Yucca 'Elena's Star' a selected clone of the BMJ hybrid #1844 (Yucca glauca X hybrid # 1402) made by Benny M. Jensen in 2003, BMJ #1844A.
Yucca faxoniana X glauca complex
Yucca 'Floribunda' from 3 different sources, not all plants are alike?
Yucca 'Karlson' F:2 = seedling from Yucca 'Karlsruhensis'!
Yucca 'Karlsruhensis' ( Yucca flaccida x glauca)  Hybrid by Graebener (1899).
Yucca harrimaniae x nana
Yucca hybrid #500 (hybrid of unknown origin!)
Yucca hybrid #1402 (hybrid of unknown origin!)
Yucca reverschoni x thompsoniana, Texas, Rankin, fh1180.8, sown 1999.

See full list on this page: "List of Yucca hybrids in the "Jensen collection" 2009"

Yucca hybrids made in the summer of 2003.
Yucca hybrids made in the summer of 2004.
Yucca hybrids made in the summer of 2008.
Yucca hybrids made in the summer of 2009.
Yucca hybrids made in the summer of 2010.


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