Thursday, July 3, 2008

Cycads, Strelitzias and Clivias

Cycads, Strelitzias and Clivias

This morning I met up with Phakamani Xaba, who is in charge of the ‘Dell’, the central section in the garden containing the Cycad/Gymnosperm collection, the Useful Plant Garden, and the Pelargonium Collection. He also oversees the collections in the Nursery for all Cycads, Strelitzias and Clivias. I accompanied him walking the garden for a few hours, and watering the Cycad seedlings, listening to a huge amount of info I am still processing.

For the next two weeks I will be working with him and Diky, a guy working at Kirstenbosch since 30 years (!) and taking care of the cycads since almost as long. What a source of experience I will have the chance to tap into!

This is Diky with a female Encephalartos sp.

We will be doing pollen collection, hand fertilizing, and doing general repotting and caring. A special project Phakamani is doing is aimed at establishing the cause of low seed germination rates (less than 10 percent) in Encephalartos latrifrons and developing methods to improve its germination rate. E. latifrons is a threatened species occurring in the Eastern Cape Province of South Africa, and E. latifrons ex situ has been cultivated in the living plants collection since 1913. Part of my project working with Phakamani for those two weeks will be testing Encephalartos sp. pollen for viability.

As for the Clivias, mainly Clivia minata,I have to say they don’t do much for me yet. They are a South African plant, but they seem a little like daylilies; a flashy colored drive-by-plant, that hybridizers obsess about when they breed a slightly different shade of orange into the second petal from the left…but I have to be careful, this would not be the first time I undergo plant-conversion, and there are quite a few different species.

Strelitzia reginae Srelitziaceae

In contrast, I can see much more in the Strelitzia reginae breeding efforts done here by Phakamani and Diky. The Strelitzta is the signature plant of Kirstenbosch/SANBI, and the garden has successfully developed, and introduced into the market a yellow (instead of orange) selection, they named ‘Mandelas Gold’ after Nelson Mandela, who visited the Garden a few years back.

Now there are selections being done to develop a very red form, and a dwarf strain. Besides of this, there is research conducted priming the stamens with various potions (sucrose, enzyme solutions,…) to improve fertilization and seed set.

open Strelitzia pollen sacs with pollen, the stigma partially visible on the left

In the afternoon 4 of us went out with a van to Grassy Park, an old and established Township (first sign of something like a middle class) in the Cape Flats, where we went to the house of Richard and Brenda, a lovely older couple that called up Phakamani to donate a large cycad growing in their garden for the last 20 years.

It turned out to be a male Encephalartos altensteinii bearing two large cones, shedding pollen all over. We, (mostly the guys, while my job was chatting with the owners, talking about all the international volunteers they housed over the years among other things) cut off all the leaves and the cones, and dug the thing out, removing almost all of a extensive root system! No ball & burlapping needed, these cycads take transplanting very well, and you can leave them ‘naked’ like that for over a week, before replanting, without a problem. Envision the massive underground trunk, ca. 2 feet deep, and about 1 ½ foot in diameter, and add about the same mass for the above ground trunk. When you consider this is a plant that stores large amounts of water, just imagine what the beast weighted in the end!!

There is a recent pest problem in the Cycad collection outside, some borer attacks the crown of some of these very old (several hundred years!) specimen. This mainly happens when there is too much moisture, which weakens the plant. Then these insects bore right in, resulting in a very fast rotting of the crown, it getting all soft, and only noticeable when the cycad drops all of its still green leaves within days, and dies. They have adopted a regiment of removing all dead tissue down to the ground or main stem, and paint the wounds with a tree sealant. They also spray the crowns and stems very regularly with some insecticide, and hope that no more of these hardly replaceable cycads will fall to prone to that pest. Eliminating the irrigation in this section, and not planting water-loving plants between the cycads, might be the most important measure taken, as this pest only takes advantage of an already weak plant.

Leaflet arrangement in Encephalartos horridus - a very appropriate name!

1 comment:

RedHookAnna said...

Hey, Dodo, this is a real ordeal by ... transit, insect, filth, and weather. I'm so impressed that you're keeping your focus on the flora, which surely does look amazing. Polygala as a shrub??!!! Wow! Loved your comment about your co-workers, where some would have been frustrated by the language barrier, you just go ahead and enjoy the laughter. What's the soil like? Are they amending it in any way? Did you move to the new place yet?