Monday, July 15, 2019

Part 2 - Resilient Surprises

A fruitful exercise


So the drought broke in late Spring. However, there wasn't enough rainfall, over a 12 month period, to stop the death of several of our fruit trees. For the most part, they have to cope on natural rainfall. Thankfully, the Lazarus Mulberry, came back from the dead, as I described earlier. Yet there were a couple of pair trees, which not only managed to survive the drought - they bore fruit for the first time in a decade, since planted.

I was actually planning to remove the trees, this winter; believing they were never going to receive the chill hours required, to set fruit. Yet they surprised me in early Autumn, with about 10 fruit between them. It wasn't a coincidence, they made it through a particularly dry, exposed location, with no additional water. I actually did something, I haven't previously allowed happen, before. And the results, were surprising.


#1 tree, largest of the two ~
illustrating the vigorous rootstock, sucker


Because the trees were effectively, on notice to come out, I didn't maintain them. Deliberately letting the rootstock go, when I'd normally remove them at ground level. It was incredibly vigorous growth too. Which I wasn't really paying attention to, until I spotted the fruit in Autumn.

The trees earned a reprieve, I wasn't expecting to grant. But they completely turned my head, of what actually works in our hot, dry conditions. So I started contemplating the role, unchecked rootstock growth, may have played in the emerging fruit:

  • Had it flowered, and cross pollinated the grafted pear? Most likely an inedible, ornamental pear - but providing extra blooms, nonetheless
  • It's vigorous growth, was protecting the less hardy graft, in an exposed location

Either way, I learned something new from the extreme climate, and presence of a thriving (nuisance) rootstock. With hardly any natural rainfall, it managed to give the grafted pear an advantage, it hadn't experienced before. Protection. The rootstock was a die-hard survivor. The graft was more vulnerable. For a period, they were beneficial, growing together. I pruned back the two pears recently though, and observed how each graft behaved differently.


#1 tree, graft


Both pears were purchased from the same nursery, at the same time, but their grafts were slightly different. I recently removed, two rootstock shoots from the tree above. Only two. But they were vigorous, and growing into the tree. However, because there wasn't a lot of rootstock trunk, above ground, I suspect it limited the amount of suckers coming up from the ground too.

The largest of both pears, this tree bore the most fruit. It seems, having the graft closer to the ground, limits suckers. Enabling the grafted pear on top, to dominate. The other (much smaller pear) however, had a very different story to tell.


#2 tree, graft


The graft had been placed, much higher up the rootstock. I've always had problems with this particular tree, growing a ridiculous amount of suckers from the root. In the nine years I was maintaining the tree beforehand, I was constantly pruning them off at ground level, during the growing season.

This created a kind of lean to the pear, where the rootstock was attempting to allow suckers to emerge at ground level. I struggled to keep up with them, on this particular tree. No matter how each rootstock, behaved differently though, it still had the same vigorous growth during the drought. Which shielded the grafted tree, from the extremes.


Pre-pruning, #2 tree


This was nearly ALL rootstock growth, on the smallest tree. It's most likely, a European, inedible pear - differentiated by the red leaves. The grafted pear, still has green leaves - which can hardly be seen. Normally, this kind of rootstock parasite on a grafted tree, would ultimately be the end of the graft. It simply couldn't compete, and may have (in the right conditions) been overcome by disease. I suspect in a wetter climate, it may well have died.

In a drought, however; it had the complete opposite effect. It acted more like a shield for the graft. While the extreme conditions, put the graft in stagnation - the hardy rootstock had no issues, pushing out growth in the barely noticeable rainfall, we had.


#2 tree, rootstock removed


Same tree, minus the rootstock. See the lean?  This is what you don't want on a grafted tree - a gazillion suckers, emerging from the rootstock, acting like a coppice. It was pushing the rootstock over, which had the graft on it. All to make room for the cancer like suckers, which didn't have a graft to hold them back.

This grafted tree, was more in danger of death by rootstock, than #1. But I still have hopes, it can be rescued. Mostly because it has four Leucaena trees, self-seeded around the pear. I pruned back the biggest of the Leucaena, which I mulched the pear with recently. Along with (the pears) thorny rootstock shoots. By pruning the Leucaena however, it also pruned the nitrogen fixing nodules, on it's roots, underground. Which will go towards feeding the pear, nitrogen.

Now I haven't been the only one pruning the Leucaena. The kangaroos have already been doing that, since winter. Because there's less nutrients in the grass, the protein in the Leucaenas (and pigeon peas) helps sustain the kangaroos, better. Especially the lactating mothers.


Pre-pruning, #1 tree


This is the other, much larger tree. Even with two shoots from the rootstock (red leaves) it's clear the graft is dominating. At this point, it's a symbiotic relationship instead of a takeover. Even though the grafted tree, is strong - the rootstock still contributed, as a shield from excessive heat, loss of moisture, and protection of the blooms, when they emerged. This was at a time of extremes, it was most needed.

Pruning these suckers off though, proved to be a little hazardous. As they had rather large thorns on them. I'm sporting the tip of one, in my thumb, presently. Yet it made fantastic chop and drop, material, to help feed the tree and shelter the soil underneath. Which is beneficial for the approaching summer months ahead.


#1 tree, rootstock removed


I don't like to prune my fruit trees, as is recommended. In my climate, I really cannot afford to open up the centre, like a vase. I need to protect my trees from heat exposure. So while I will prune back some inner branches, which may become a problem, I'm more inclined to let something else, determine how I shape the trees.

It's all about the balance. I've taken notes from Masanobu Fukuoka's book, on not pruning trees. Instead, trusting that the form of the tree, shaped by nature, is a better design. I see that very clearly, in the short-lived Acacia trees, around here. Whose branches snap off, that are out of balance with the rest of the tree. When the winter winds, kick-up, the rest of the tree topples over. A good lesson in why balance is important.

What informs which branches are removed, is determined by what branches I want to counter balance another. I will keep a bud on the inside of a tree, or close to another branch (for example) if it creates balance with another bud, on the same branch. Pruning is never about what shape I'm looking to create. Although it is in the back of my mind. Creating balance is my main concern.


Caught in the middle


To highlight what can become an issue, in wetter climates than mine however, is what's happening in the centre of the trunk. Leaves can gather, become moist and cause disease. This is where a vase shape, would make more sense. So it's easier to observe the centre of the trunk, and allow the wind to dislodge any debris.

This is something I have to keep an eye on, should we encounter a wet year. It does happen, occasionally. Approximately every 7 years. It sounds silly when I put it like that, but there's no point keeping the trees alive in dry times, if the occasional wet one, could be their ultimate demise.


What's inside?


Once the rootstock suckers were removed, it exposed the fruit, protected on the inside. Unfortunately, I had to remove fruit early, because the ones on the outside of the tree, were already being eaten by parrots. Which only demonstrates another reason, the hardy rootstock was beneficial. It's thorny branches, made it difficult for larger birds to gain access to the fruit.

Needless to say, I wasn't expecting any fruit at all from these trees! They were essentially destined for the compost heap. So we brought our unexpected bounty, inside, like a pair of possessed Gollums.


That's all folks!


Only a mere, ten years, in the making. Five fruit. I know what you're thinking though. Was it worth it? Maybe not to some. It's not even a proper meal! But what it represents to us, is site specific knowledge. Each edible plant, that has lived, and/or, died here, had to pass a range of different conditions, first. We observe each success and failure, to learn how that knowledge is best applied.

This is especially beneficial, if you don't have a lot of money to throw at artificial inputs. To see this fruit emerge, in one of the most challenging growing seasons yet, when I had other trees dying in the ground - well, what's that worth? It's a chance at improving our odds, with edibles in the future.

I never would have predicted, letting the rootstock emerge in the dry - was essentially a lifeline for the grafted tree. Maybe it's the missing wildcard, necessary, for adaptation in extremes? Maybe not in every climate, or even every year. But sometimes, it might be necessary to let your expensive grafted fruit trees, perform in a slightly different way.

8 comments:

  1. Your garden and your climate are very different from mine, you document your struggle very well, I can't imagine being in drought every year. Our summers are dryer, but still we have enough rain through the year to support a lush garden. The biggest problem we both have is finding the right plants which will live in our gardens, I'm on pure clay whichcan cause issues.

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    1. I'm always happy to hear, others have better growing conditions than ours. Because if it was drought all over the place, our planet would be in serious trouble. I empathise with your clay dilemma too. As we have a lot of it. These two pears are actually on clay, but we put a lot of chop and drop material down, every year, to help provide more organic matter.

      If you know a good tree nursery, have a chat with them about their rootstock. They might actually provide one, more suitable for growing in clay. So you can have your edibles trees, on bulletproof rootstock. I guess you must be good friends with gypsom though. As that really helps too. :)

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  2. Extremely interesting Chris, with valuable observations and lessons learned. This is the kind of thing that results from taking time to observe nature at work. I remember Masanobu Fukuoka's orchard learning story! Then I think about Sepp Holzer's non-pruning method. In the end, we have to see how trees we plant respond to our own ecosystems. I so agree it's all about balance, which is what nature constantly strives for. Your observations are valuable clues of how to cooperate with that!

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    1. Thanks Leight. I love Masanobu Fukuoka's approach to growing edibles. Also Sepp has a good take on companion planting, vines with fruit trees, getting better yields and protection for both. It's the kind of non-textbook thinking, which seems to have better odds in the field. I will tend a tree, but if I don't have to become a slave to it, it's more likely to survive, lol. Because I cannot be there, all the time, to see what it needs.

      So I'm glad you mentioned Sepp with Fukuoka. They really have their finger of the pulse, of what nature demands of the trees. In particular, how it's not all about isolation to the environment. It's about how the environment shapes the trees. I'll mention Mark Shepard, here too. With his take on mass planting edible trees, and letting nature weed out the ones in the wrong position, or are too weak.

      I guess because edible trees are expensive though, we tend to get precious with them. It's funny how delegating the trees to death row, however (ie: me not interfering) revealed how they can adapt without us. ;)

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  3. Wow, that's a complex post. I will have to read it again more slowly to get the sense of it. I have two pears and neither of them has ever produced any suckers from below the graft. I've tried to keep them low and pruned, so as to be able to net them from the birds, but it's a continuous job which I could well do without. I'm not sure about apples, but none of my apples has produced any growth from below the graft either, yet all my seedling grown apples have. I also have what I think is a seedling grown plum which I haven't pruned and which has developed a beautiful open shape. I'm not going to touch it. I don't know Fukuoka's work on pruning so must look it up. I would rather let the trees do their own thing and maybe, as you say, just look at balance issues and be grateful for whatever the birds don't get. It's so complex.

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    1. I think it all depends, what's being used as the rootstock, Bev. For pears in Australia, two types of ornamental pears are used for rootstock, and one variety of Quince. Maybe you have the "Quince" variety on your pears, and that's why they don't sucker as much? An ornamental pear, is closer to the wild strain of pear - which grows more like a thicket, than a single trunk.

      Which might explain why your seedling apples have suckers too. As you don't know what part of the parent genes, are being expressed - maybe more in the wild category too? Before we hybidised edible trees to express only the desirable traits we wanted, they were closer to the wild varieties. Which were very vigorous growing thickets, more than single trunk, trees.

      I like the sound of your seedling plum too. I haven't had experience growing plums, so I don't know their natural form. Maybe it's meant to be open? Either way, it sounds like a nice tree. I wonder what the fruit will eventually taste like?

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  4. Chris, I had written off the dwarf mulberry I had in a pot and was set to send it to compost heap when I noticed little leaf buds on the bare branches. Now, it's fruiting ... go figure!
    I think resilient surprises are sometimes the best ones because they get us thinking and, as I will have to do, learning a bit more about the plants and the conditions they can survive in. What did you make with your pear harvest? Meg

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    1. Super news about your mulberry. Another survivor of extremes. Happy for you!! All, but one of the pears, were edible. They developed some kind of rotting in the centre, by the time they had ripened. The one we ate though, had a slight astringent quality.

      Parts were sweet, but then others were astringent - or bitter tasting. Which could be an indicator, the graft, cross-pollinated with the rootstock. An ornamental pear, and highly inedible. Obviously, we still have a lot to learn about keeping pears. :)

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