Pear tree graft

[fishpond]

I have a Concord pear tree on QA rootstock.
The tree is approx 12ft tall and is struggling to survive due to chlorosis (I believe) caused by being on alkaline/chalky soil.
I have this winter, tried to remove the tree from its spot, but due to a lack of fibrous roots and 2 big tap roots it had to stay even though one of the taproots has now been severed, the one going straight down (done deliberately to attempt to get some fibrous roots growing)(seemed like a good idea at the time)
When this tree was planted soil was excavated from the planting hole down 2 foot and a mixture of soil, compost and well rotted manure was added together with some growmore.
I should be receiving some Pyrodwarf rootstock this next week.
Is it possible to do a graft of this onto the tree without affecting the other rootstock (how), or should I wait until next spring and take a proper cutting from the tree?
What would you do?

[FB.]

When your Pyrodwarf rootstocks arrive next week you should be able to take grafts from your Conference pear and put them onto the Pyrodwarf rootstock.

The best graftwood is from shoots which grew strongly the previous season. Weak-growing wood or grafts from diseased (especially cankered) old trees often have poor 'take' rates.

When you cut the excess length off the rootstock stem prior to grafting, poke the bit you cut off into a cool, damp, three-quarter-shade spot for a year because sometimes they will root (I havn't tried with Pyrodwarf but certain other rootstocks will root from cuttings; ease of rooting being a highly desirable characteristic for a rootstock).


Yes, quince trees and quince rootstocks are not so happy on alkaline soils nor on dry soils. Pyrodwarf and Pyrus are more tolerant.
Pyrodwarf is a much better choice than Quince stocks for difficult sites. It is about 1.5x the vigour of Quince A, although in poorer soils even vigorous rootstocks can be dwarfed while the dwarf rootstocks simply die.

Another bonus of Pyrodwarf is that being 'pear' rather than 'quince' it seems to be fully compatible with all pears, whereas Quince A and C are only semi-compatible and in some cases certain pears are short-lived, weak and sickly when grafted onto Quince stock - sometimes interstocks are used to bridge between Quince stock and a quince-intolerant scion.
Most 'dwarf' rootstocks (apple, pear, plum) probably work on a partial incompatibility between the two parts which interferes with their water and nutrient exchange and makes the tree grow more slowly and fruit more because the poor scion:root nutrient exchange stresses the tree (and stress is good for fruit bud formation).
The poor sap exchange across the graft is probably one reason why dwarf rootstocks are notorious for producing 'suckers' (or the scion own-rooting if planted too deep) as the two parts try to bypass each other.

[FB.]

The tree is approx 12ft tall and is struggling to survive

I wouldn't say 12ft was 'struggling to survive'. That's normal for Quince rootstocks, especially with weak-growing scions like Concorde.

My Concorde pear is on Quince A, and it definitely is 'struggling to survive'; it is ten years old and only about 3-4ft in size (its neighbouring QA pears are about 1ft bigger). It is on a shallow, dry, sandy-gravelly-chalky soil.

I even have some pears on seedling stock (and apples on M25) but they won't reach 12ft in my lifetime.

[fishpond]

Many thanks FB
I have been over this tree many times, even with a magnifying glass, the only conclusion I have reached is it is a cultural problem caused by the rootstock.( last year, if I remember correctly, it didn't even flower, it has produced fruit in previous years but never in any quantity) There is another one approx 25ft away which fruits prolifically and always has done, both bought from RHS Wisley and both planted at the same time.
It will be interesting to see what it does (or doesn't) do this season.
I might plant the Pyro stock out of the way until next year.
The poorly one? has got plenty of fruit buds, so, yeah, it should be interesting to see what happens.

[FB.]

Chalky soil could be interfering with nutrient uptake; iron chlorosis is the yellowing of leaves, but I think the excess calcium in chalk soil can interfere with absorption of other metals - including potassium which seems to be required for blossoming/fruiting.

My Concorde is a light cropper compared to my other pears, even taking into account its slower-growing habit. On a same-size tree basis I'd guess it produces half the crop of Conference.
I can't say that I find the fruit to be anything special either; Conference is not only much heavier cropping but it's tastier than Concorde in my soil.

Aside from the chalk/alkaline soil problem that can affect nutrients (especially when using quince), is it possible that the pear is infected with a virus that's causing it to decline in health and/or productivity?*

[fishpond]

I will see how it goes this season.
If it goes pear shaped again ,I will take some photographs and possibly send some stem to the RHS
FB, Once again, Many Thanks for your advice.

[orangepippin]

Most 'dwarf' rootstocks (apple, pear, plum) probably work on a partial incompatibility between the two parts which interferes with their water and nutrient exchange and makes the tree grow more slowly and fruit more because the poor scion:root nutrient exchange stresses the tree (and stress is good for fruit bud formation).

I don't think dwarf rootstocks cause the tree to grow more slowly. Almost all of them make the tree fruit at a younger age than would otherwise be the case. They mostly work by making the tree reach maturity at a younger age (and hence lesser height). I agree with your point that there is a degree of species incompatibility between quince and pear, which can cause issues with the Quince A and C for grafting pears. However this is not such an issue with apple rootstocks, where even the most dwarfing rootstocks are very highly compatible with all scion varieties.