Replant disease: Quince A -> Pyrodwarf

[chrisdb]

As part of my general clearout of things that aren't working, the next thing to go is the Concorde pear on Quince A, which after 6 years is a twiggy thing shorter than me (although it does fruit if I let it). Since the Beurre Sterckman and 20th Century pears on Pyrodwarf are now actually growing at a reasonable rate, I'm planning to replace the Concorde with a Martin Sec on Pyrodwarf as well.

Has anyone replaced a pear on QA with Pyrodwarf? I was wondering if the switch of rootstock species from quince to pear would help with replant disease, or if I'm going to have to dig out and replace a lot of soil. Normally I try to replace with a very different species (e.g. pome to stone and vice versa) but this time the goal is just to have some slightly more vigorous trees of the same species.

Also, has anyone tried Martin Sec, either cooked or raw?

[Hereford fruit grower]

I haven't tried it but to illustrate the effect soil has, my pear trees on quince C are 1.3x taller than I am after 5-6 years and produce 0.5 m/yr of extension growth which I remove by summer pruning. Yet as far as I can tell quince C is more dwarfing than quince A.

The dwarf trees also produce as much or more fruit than my four trees on 'Pyrodwarf' despite being a third the size. I was IMO mis-sold PD for varieties that need an intermediate scion when grown on quince, all because the supplier didn't know about double-working (the standard late 20th.C method I think).

Are your trees under grass? That reduces growth a lot. Dwarf trees sometimes do well in a veg. or flower garden.

[chrisdb]

I haven't tried it but to illustrate the effect soil has, my pear trees on quince C are 1.3x taller than I am after 5-6 years and produce 0.5 m/yr of extension growth which I remove by summer pruning. Yet as far as I can tell quince C is more dwarfing than quince A.

The dwarf trees also produce as much or more fruit than my four trees on 'Pyrodwarf' despite being a third the size. I was IMO mis-sold PD for varieties that need an intermediate scion when grown on quince, all because the supplier didn't know about double-working (the standard late 20th.C method I think).

Are your trees under grass? That reduces growth a lot. Dwarf trees sometimes do well in a veg. or flower garden.

The trees aren't under grass, they're in the middle of a border with a bit of bare ground around them. The pyrodwarf pear, which unlike the QA is now actually growing, is in a much less favourable position next to an established hawthorn hedge.

It's not even that my soil is bad in general. Apples grow really well in our garden: I have apples on mm106, supposedly similar tp QA in vigour and planted at the same time, that are now almost 4m tall. It does seem to be specific to pears on quince. Medlars on quince grow more vigorously, but I have separate issues with them. I've read that quince rootstocks are intolerant of alkaline soils and dry soils, and since irrigation doesn't help that leaves ph. But our soil is not extremely alkaline, since we can grow most things except true acid lovers like blueberries and rhododendrons.

I do have some issues with dwarfing rootstocks. I've learned not to plant dwarfing prunus rootstocks as well, since they tend to die within a couple of years even with coddling.

[FB.]

In my experience there isn't a noticeable problem as long as it's a different rootstock of equal or greater vigour than what was there before.
So Pyrodwarf should be fine to replace Quince A.

Pears are fussy about their rootstock. Quince is used because pears are only semi-compatible to varying degrees and therefore stunted (dwarfed).
It's possible that Concorde is less compatible on Quince than other pears and as an example; Doyenne D'ete is said to be slow-growing and difficult to keep alive on Quince, but I have Doyenne D'ete on Pyrus and one on Pyrodwarf* and it's a strong grower on both rootstocks.
I'd say Pyrodwarf is at least three-quarters the vigour of Pyrus, possibly approaching Pyrus vigour in some instances.

* The Pyrodwarf pear was removed because cropping gradually declined as the local bee population disappeared. There are now so few bees here that pears don't get pollinated so it was taking up useful space which has been used for something else.

[chrisdb]

In my experience there isn't a noticeable problem as long as it's a different rootstock of equal or greater vigour than what was there before.
So Pyrodwarf should be fine to replace Quince A.

Good to know! I was a bit worried, but not too keen on digging out a wide area.

Pears are fussy about their rootstock. Quince is used because pears are only semi-compatible to varying degrees and therefore stunted (dwarfed).
It's possible that Concorde is less compatible on Quince than other pears and as an example; Doyenne D'ete is said to be slow-growing and difficult to keep alive on Quince, but I have Doyenne D'ete on Pyrus and one on Pyrodwarf* and it's a strong grower on both rootstocks.

I've had the same problem with other varieties. They also say QA needs good soil... it could be that the partial incompatibility and my OK conditions (maybe not "good" enough in some way) means that QA just doesn't work for me for pears.

Another question this raises is which rootstocks websites like Keepers use when evaluating the vigour of pears. I ruled out a number of varieties as a replacement because they were listed as low - medium vigour, and I thought better safe than sorry given my struggle so far with pears. But if I upgrade the rootstock and the scion is much more vigorous on pyrus then I might massively overshoot.

I'd say Pyrodwarf is at least three-quarters the vigour of Pyrus, possibly approaching Pyrus vigour in some instances.

What I really want is a tree I can maintain at <= 4m tall and wide, a similar size to my free standing apple trees. I think that I can probably do that with Pyrodwarf, although my experience of its vigorous years are just starting. I first planted it 3 (I think?) years ago, and the earliest tree is only now really taking off. I've found it very, very slow to establish, and it didn't grow much faster than the QA trees for the first couple of years.

I think it also causes later flowering - I have a Beth on QA and a Beurre Sterckman on Pyrodwarf, which should flower about the same time, but the Sterckman is significantly later to hit peak flowering. The Martin Sec I've ordered is supposed to flower a bit earlier, but given the offset it'll probably flower at the same time as the Beth pear.

There are reports that Pyrodwarf makes fruit a bit smaller, which might be a bit of a concern since Martin Sec is a small fruited variety mostly used for cooking in any case, but fingers crossed.