Gondwana Archives - Oceanside Garden

Gardener’s Log – September 2021

The first signs of fall are here. I am sure every gardener has a few tell-tail signs that they use, but one of the plants for me has always been the cyclamens, and in particular Cyclamen hederifolum. The bright little pink flowers push through the surface, just as leafless as any of the naked ladies.

A new one of those this year is Lycoris radiata, the spider or hurricane Lily. Its bloom spikes are 10″ to 12″ and much larger. The blossoms are quite a striking red.

As for trees, the first to start turning are always the dogwoods – Cornus ‘Venus’. They start to color up by the beginning of September, putting on their orange, then red and finally burgundy cloak. The only thing that stops their display being magical is that every leaf turns on its own schedule, meaning that the tree is a combination of all colors and not a single bold display.

Start of the Rainy Season

We have still to have the first rain of the wet season and much of the garden is looking totally parched. That rain is expected later this week and they say it could be 1″ to 3″, so quite a soaker. Let us hope that it starts gently so that it can properly wet the soil, because sand resists water.

Update – the rains came and we had 2.5″ – and at least some of it soaked in, but the soil still remains quite dry.

Lots of work over the weekend got the area between the Garden of the Giants / Whimsey Way and the next-door forest area cleared and planted. Some Woodwardias have gone in along with an Enkianthus, candelabra primulas (Primula beesiana), and other plants that should provide some interest throughout the year. They were selected to provide a transition to the more natural area, rather than a last hurrah. Everything was selected as being deer resistant, but our local deer aren’t very smart and cannot read labels. Over time, their aching tummies will tell them, assuming the plants survive.

Update – the deer have decided that they like Onoclea sensibilis – the Sensitive Fern

La Nina is supposedly forming in the tropical Pacific this year and that traditionally means a cooler and wetter winter. Given the dryness this year, that will certainly be a change, and most of the Gondwanan plants will probably appreciate it. It does mean that I will have to take special care to bring sensitive plants in for some protection because it may mean some arctic blasts.

Looking Back

Talking about Gondwana, my Facebook account reminded me about a photo I posted a year ago. The rock walls were still going in. I decided it would be nice to do a side-by-side to show the plant progress in a year.

It looks as if the Banksia specioca, that I grew from seed and was doing so well in Gondwana, has very rapidly croaked. The tips of the new growth curled and then the whole plant has yellowed. I am not sure it will re-shoot from the base when moisture becomes abundant, or if that is the end of story. It will be a shame if that is the case.

The rains did indeed come, and all the plants are much happier. It takes a lot of rain to completely re-wet our soil. After 2 1/2″, one of the outdoor moisture sensors is saying that the soil is at 76% saturation and the other one remains at 12%. My guess is that most of the water ran off in that area rather than soaking in.

Seed Starting

The latest batch of seeds arrived from South Africa this week and so there has been lots of activity getting those started. Most of the seeds are for somewhat diminutive bulbs and will take 3 years before they get to a blooming size. The others are seeds of Protea cynaroides, Protea lepidocararpodendron, and a yellow hybrid Leucospermum.

These need a little more pre-treatment before sowing. Some like a hydrogen peroxide treatment to loosen the other coating and then soaking in smoke water. I am trying to germinate them in a sterile condition by having them against a damp paper towel. That way I can immediately see if they germinate or if there are any fungal problems. That can be a significant issue because they may well take 3 or 4 months to germinate.

Gondwana Extension

Gondwana got a small extension. On the extreme left side, when looking up the hill, the juniper was pushing into the Grevillea and the retaining wall behind that had never been finished. That was corrected and then the nest tier above that was partially put in and the soil dug. Getting rid of all of the Salal root is important because that has a habit of sprouting for many years to come and I don’t want to be pulling out those roots after Protea family plants are in place. Three new plants were added – Protea eximia, which I grew from seed, Grevillea ‘Robyn Gordon’, and Leucadendron ‘Jester’. The variegated leaves of Jester should provide a good tie into the red flowers of Robyn Gordon and the bright yellow of the foliage across the stepping stone path into the conifer forest.

Leucadendron 'Jester' — Leucadendron ‘Jester’

Aloe Plicatilis

What a difference a year makes. I was going through plants looking to see what needed potting up and realized how much the Aloe plicatilis has growth since I got it earlier this year. The first picture was taken in February and the second in September.

This is exciting because I thought its growth was going to be a lot slower. I am not sure if that is its first branch developing in the center.

Weather Summary

This has been the end of a long dry spell and over the last few days of September we picked up about 4″ of rain to give us a total of 5.13″ for the month. However, that still left us with a deficit as compared to last year when we had 6.90″ and 8.99″ the year before. Temperatures were cooler by 3.2 degrees and along with that, winds were considerably higher accounting and more westerly – which explains being cooler.

General

Proteoid Roots

The Plant kingdom is amazingly diverse and still quite unknown in many ways. As I have become fascinated with plants from the Proteaceae family, I have found out just how recent our understanding is about these plants and some of the things that make them special. I wrote about one of these some time ago, and that concerned their requirement for smoke as a way to break seed dormancy. In the past people thought they needed fire, but in the 1990s researchers found that it is chemicals in the smoke that was the important element. Since then, propagation techniques for many plants that appear after fire has swept through an area, have been revolutionized. Plants that used to have germination rates of a few percent, now see 90+% germination rates.

But what I want to talk about in this blog are roots. Again, this is a fairly recent discovery, this one going back a little further to 1960, but still not fully understood to this day. A hundred years ago, it was noticed that some Protea had roots that were different from others. Nobody knew why. The reason why I am writing this blog is because I saw these roots for the first time when I was repotting a Banksia. The term Proteoid roots was established in 1960 by H.M. Purnell who described them as a root with “dense clusters of rootlets of limited growth.” After extensive examination they were found in a number of species and genera within the Proteaceae family and today it is known that every genus except one grows these roots when required.

Proteoid roots on a Banksia ashbyi ‘Dwarf’

Purnell suggested that these roots were associated with the uptake of nutrients from the impoverished soils found in South Africa and Australia where these plants naturally grow – similar to the soils I have on the Oregon Coast. Most plants form a symbiotic relationship with mycorrhizal fungi.

Mycorrhizal fungi extract the minerals necessary for plant growth from the soil and give them to the plants in a liquid form that can be absorbed by the plant roots. In return, the plants support the fungi, giving them sugars and starches. But mycorrhizal fungi appear to not exist in the soils that these plants evolved in. This could be for one of two reasons: either the mycorrhizal fungi did not or could not live there, or that the soils are so lean that the plants cannot afford to give up any of their product of photosynthesis. These plants basically never shed their leaves.

Gondwanan roots

Proteas evolved in the ancient supercontinent called Gondwana, but proteoid roots could be older than that because they have been shown to exist in plants from the Northern Hemisphere and thus arguably evolved when Pangea existed (about 250 million years ago). Other species have been shown to use this technique, especially those from the Mediterranean region. Some researchers disagree and say that the Proteoid root clusters from the Northern Hemisphere are different and may have been an independent development.

One paper suggests that proteoid roots in Lupins only developed 2.5 to 3 million years ago and that the only plants outside of the Proteaceae family that have these roots are nitrogen fixing plants. While that may be true for Northern Hemisphere plants, other Gondwanan plants do have similar root forms, although they appear to not be called Proteoid roots. The White Lupin (Lupinus albus) is an interesting Northern Hemisphere example because it is a food crop that exhibits this root formation, and so this plant is receiving a lot of attention from agricultural companies. This may finish up solving some of the many unknowns about these roots, but they may also be different from the true proteoid roots.

Without the mycorrhizal fungi, the plants have to extract nutrients themselves and that is the job of the proteoid roots. Normally the phosphorous is so tightly bound to other materials that it is not available to the plant. Proteoid roots exude acid, carboxylates, and other substances into the soil that break down minerals and allows phosphorous, iron, copper and other nutrients to be absorbed.

This is not a slow process – it is done in a burst over a period of just 2 or 3 days. It is believed that this is done to stop other microorganisms from being able to sniff them out and taking some for themselves. They have become so efficient at doing this that if you were to feed these plants with a balanced fertilizer, you would probably kill them. They would literally overdose on phosphorous. Some studies have found that Proteoid roots are up to 13 times more efficient at absorbing phosphorous that typical roots.

More Research Required

A lot remains unknown. The plant doesn’t always have these roots. They are grown at times and then reabsorbs them at others. It is expected that they are created when certain nutrients are deficient, but research so far has been inconclusive. It is also unclear why they then remove them rather than just keeping them until needed. If you want to learn more about this you might be interested in reading this research paper from 1999.