Prickly pear pads – MCSS plant sale – 10th & 11th of September 2016

For folks who have purchased some pads of the prickly pears from me at the annual show and sale, here are some photos of some of these plants in the garden and in nature, and also a link to the USDA plant profile.

Opuntia fragilis:

http://plants.usda.gov/core/profile?symbol=OPFR

Opuntia humifusa:

http://plants.usda.gov/core/profile?symbol=OPHU

Opuntia phaeacantha:

http://plants.usda.gov/core/profile?symbol=OPPH

From the flyer:

Prickly pear cacti may be offered as pads, and that’s what these are. This cactus needs to be planted in a certain way: it needs to be rooted. I root my prickly pear cactus by laying the pad on the ground the way a dish sits on a table, but a little more on an angle (like a saucer or plate tipped slightly on one edge). The edge that I tip toward the ground is always the base or narrowest part of the pad, where the pad was cut off the main plant. I ensure that edge tipped down to the ground has good contact with the ground (soil, not rocks) and that it is never allowed to remain damp or soggy for any length of time. I never bury the pads much. Finally, I ensure that the pads don’t grow legs and walk off — I keep the part tipped to the ground using a wire coat hanger bent in a U-shape and stuck in the ground.
Well-drained soil is what these cacti are used to. These particular cacti are growing outdoors in sandy loam, sand + gravel, or potting soil + lots of perlite. They are grown in the full sun (south and west sides of the house) and not anywhere where water can pool, nor where the soil is soggy.
I plant them anywhere between April and early October. On occasion, I have stored some of my prickly pear pads indoors in a dry, cool, dark place over the winter when I could not plant them by October. But all these pads for sale were freshly cut within the last two weeks.

Pollination and hybridization of yucca species

Yuccas are pollinated by the yucca moth. A nice introduction to this is given in this article: http://www.fs.fed.us/wildflowers/pollinators/pollinator-of-the-month/yucca_moths.shtml.

Just as there are many species of yucca, there are three genera and many species of the yucca moth. One genus, Tegeticula, is shown in this article with twenty species: http://en.wikipedia.org/wiki/Tegeticula. Another genus is Parategeticula. And there is a genus of false yucca moths, Prodoxus: http://pdfsb.com/yucca+moth+manual.

Side bar: In my own garden in Michigan I have many Yucca filamentosa, which are pollinated by the Tegeticula yuccasella. Y. filamentosa is classified as native or naturalized here, depending on what source of information you are reading. In any case, every year there is a period of intense yucca moth activity, some of which I have photographed and posted here: http://www.flickr.com/photos/mikesmode/sets/72157625733198704/detail/.

The National Center for Biotechnology Information has two abstracts on its web site that touch on the subjects of hybridization of yucca in nature and their pollinators:

• Abstract #1 entitled “Asymmetric hybridization and gene flow between Joshua trees (Agavaceae: Yucca) reflect differences in pollinator host specificity” located here: http://www.ncbi.nlm.nih.gov/pubmed/23190404.
• Abstract #2 entitled “Limiting cheaters in mutualism: evidence from hybridization between mutualist and cheater yucca moths” located here: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1559949/

The full publications are available for download from the NCBI web pages listed above.

Agave parryi in Michigan

NOTE: This blog entry is the first in a series about gardening adventures of growing cold-hardy cacti and succulents in Michigan, some native, most non-native.  Each blog entry is paired with a photo album in Flickr, whose links are provided in the blog entry.

In spring of 2009, I purchased five species and a few subspecies of cold-hardy Agave.  The purchase was made both to develop my knowledge of gardening such plants out of doors and with the sincere intention of making these plants survive and thrive.  One of these was Agave parryi.

A. parryi - May 2009

This Agave parryi was nursery-raised from seeds collected near Flagstaff, Arizona, according to the tag.  This plant was approximately 5-6 cm in diameter when I received it.  The photo at right was taken before the plant was transplanted into the rock garden.  In mid-May, all of the Agave were transplanted from their tray and into the rock garden.  June through November were quiet months in terms of weather, and only a few pictures were taken.  The plant grew a bit and remained very healthy all these months.  The following photos illustrate the condition of the plant over several months, starting with this one of June 2009:

A. parryi - June 2009

Next are photos taken November 2009 / December 2009 / January 2010 / February 2010.  (Click on each photo to see a larger version in Flickr.)

The Agave parryi fared very well through the winter months, showing no signs of stress or damage.

A. parryi - 06-Mar-2010

A. parryi - 16-Mar-2010

When March 2010 arrived, the temperatures rose to between about 50-67 degrees F. during the day and around freezing at night.  Interestingly, when the temperatures warmed, a few areas of discoloration appeared on the plant.  The right two photos, taken 06-March and 16-March, respectively, show these areas.  Notice a few brown circles and one triangular patch.

Since then, nothing has changed with the condition of the plant.  I will update this blog entry with new data and commentary on the health and status of this plant as time progresses.

The corresponding Flickr photo album that is a companion to this blog entry is located here: Gardening – Agave parryi.

More to come with several other Agave species and subspecies.

Regards,

Mike

Seed germination / genetic programming

Ultimately a seed is a capsule of genetic programming that is designed to process inputs and produce outputs, just like a computer program.

When a seed hasn’t germinated after exposure to the prescribed inputs, one would surmise that either a) it hasn’t received the correct stimuli to start the germination process, or b) the seed is faulty/diseased/somehow compromised.

Some seeds appear to need multiple prescribed germination cycles, stratification, scarification, &c.  Again, either a) or b) above is occurring or has occurred.  Opuntia seeds are especially like this.  It takes just the right combination of inputs to trigger an output, and unfortunately we humans haven’t decoded the programs to tell us what the exact inputs are, over what periods of time, in order to produce the desired output.

I came across this interesting resource while searching for info on multiple germination cycles and searching for the terms “genetic programming” + “seed germination”:

http://www.seedbiology.de/germination.asp

But it is surprising how little material can be found looking at this from the perspective of a programmer.