Dragon’s Blood Tree

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Dracaena cinnabara tree, image from Wikipedia, click on the image to see the original (large) image at Wikipedia

Dracaena cinnabari is not a cactus, but it is an amazing plant. D. cinnabari is endemic to Socotra Island in Yemen. Its common name, dragon blood tree, derives from the reddish sap obtained from the tree that is used as a dye or a medicine. Wikipedia reports that the red resin was used in dying wool, gluing pottery, as a breath freshener and as a lipstick. Purportedly, the red sap has been employed in magic rituals.

Some sources suggest that D. cinnabari was widely distributed over Socotra Island in the past, but while it is still widespread, it is in scattered populations. It is not clear why overall numbers of the tree have declined because Socotra Island is not yet subject to typical ecological pressures (eg, urbanization, ranching). The trees typicall grow “areas affected by the mists, low cloud and, in particular, the constant drizzle of the monsoon.” Perhaps such areas are not as common as in the past? One source reports that there is circumstantial evidence of drying in the region over the past few hundred years.

You can find out more about D. cinabari at the Arkive. 

Posted by: Joe Shaw shawjoej@gmail.com

Potting Soil: to Bake or Not

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Garden Soil

A brief discussion on a cactus email list recently got me thinking about potting soil for cacti: to sterilize or not to sterilize. This is a topic that stirs passions.

For what it’s worth, I don’t use sterile soils in my potting mix, but I use “clean” ingredients. Thus, for small amounts of soil I use packaged potting soil (typically a loam with compost) as a base. I mix the base with coarse sand and with perlite or pumice. For general use I add each part in equal volumes. Because I use packaged and/or composted ingredients, I don’t worry about insect eggs or fungal inoculum, and I don’t heat treat the ingredients.

However, if I used soil right from the garden (as in the photo) I’d be sure to bake it for 2 hours or more at 200 degrees F (about 93 C) to kill insects and some pathogens. If I threw in a handful of compost (from the compost pile), I wouldn’t bother to heat treat the compost because I’m happy with the “cleanliness” of composted ingredients.

Other folks feel differently about the matter and don’t take special efforts to kill organisms in their potting soils, heating or composting. I guess that, whatever works for you is what you should do.

Posted by: Joe Shaw shawjoej@gmail.com

Grusonia bradtiana

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grusonia bradtiana

Grusonia bradtiana, by Alexander Bunkenburg, click on the image to find more of Mr. Bunkenburg's Grusonia images at Flickr

Grusonia bradtiana is found in Coahuila state in Mexico; perhaps it is found in adjacent states. The plants have beautiful flowers. Unlike many Grusonai species, G. bradtiana has a strong vertical presence as well as a horizontal presences. The stems can cover a yard or more with horizontal growth, but the branches can reach 2-3 feet high.

Over time, G. bradtiana has had several names including: Opuntia cereiformis, O. bradtiana, G. cereiformis, and Cereus bradtianus. By 1919, taxonomists had placed the species in the genus Grusonia, and there it remains.

There is not much information about G. bradtiana in the published literature. There is a publication called, “Seedling development in Grusonia Bradtiana” by Margaret Wheatley Hamilton and published by the Univesity of Oklahoma (a thesis perhaps).

grusonia-bradtiana
Grusonia bradtiana, by Alexander Bunkenburg, click on the image to find more of Mr. Bunkenburg’s Grusonia images at Flickr

 

Posted by: Joe Shaw shawjoej@gmail.com