I was following the discussion of grafting pears on quince on another forum (Cloudforest Cafe) and the moderator, Axel, who is also on this forum, had some really interesting things to say.

He mentioned that pears are not grafted onto quince anymore, because they have found incompatibilities after 8-10 years of most pears on quince, and that some get fireblight very badly. I have noticed a disease on one of the four varieties on my quince rootstock pear tree. A nursery he quoted mentioned that they are trying
new types of rootstocks. Here is what they said:

"DWARFING PEAR ROOTSTOCKS For many years, pears have been grafted onto quince rootstocks to obtain dwarf trees analagous to apple trees dwarfed on Malling 9. Most varieties of pears are more or less incompatible on most quince clones (but in several instances, including Bartlett on Quince A, expression of incompatibility may ofen be delayed until 8 or 10 years or more in the orchard). All the quince stocks we have tested have been quite susceptible to fire blight and most are somewhat winter-tender. Even so, there are many outstanding plantings of dwarf pears in commercial production.
At Cummins Nursery, we graft onto Quince A and Provence Quince only those few varieties known to be compatible. We are trying now two new dwarfing stocks, both Pyrus communis-- Pyrodwarf and Pyro 233. "

At our scion exchanges, do we graft pear onto quince or what? With an interstem like winter banana, how big would the interstem have to be?
Thanks
John S
PDX OR

Here in Oregon the native hawthorn, Crataegus douglasii makes a good semi-dwarf pear rootstock. I have Bartlett, Fall Butter and Old home on one C. douglasii tree and they've been there for about 40 years. The hawthorne suckers some, but it's manageable and suckers less if you just mow, not cultivate, around the tree. Dr. M.N. Westwood at Oregon State U. did tests of C. douglasii as a rootstock in the 1960s and found the same thing - it makes a good semi-dwarf pear stock except for the suckering.

That's a great idea, Lon. The native Douglass hawthorn is the one with the small black-purple berries and the small hard seeds inside, right? I believe they have them growing at Hagg Lake. I think I'll gather some seeds because the fruit is ripe right now. As I recall, hawthorns don't grow from cuttings.

Does anybody know what we do in the society for grafting pears? For the make a tree orders, they must graft pears onto something.
John S
PDX OR

Douglas hawthorn is everywhere in the Willamette Valley. It practically lines the fences along parts of I-5, and you'll find it growing around a lot of places where birds roost. You should be able to dig both suckers and seedlings from lots of places like that. I leave seedlings of it around here whenever they come up in an unobtrusive place and use them as rootstock.

Quince isn't reliably zone 4 hardy so all my pears are on seedlings of either Winter Nelis seedlings or Pyrus Betulifolia. Winter Nelis is said to be semi-standard in the same sense that M.111 is for apples. Let's just say that the trees get big and there's far more vegetative growth than fruit. To plant stuff on quince, I'd have to build a rather large porch.

Here in the frozen north we plant pears for our heirs.

FrozenNorth:
If you have hawthorns in your area, you might try them as pear rootstock. Not all pears work on all species of hawthorn, but enough to make it worth the try. They also work on many Sorbus (Mt. Ash).

I grafted several pears onto my Shipova tree, which is a natural hybrid between pear and mountain ash. They took. Around Portland, I would say the vast majority of the seedling hawthorns I see are the Washington hawthorn, which I assume won't accept pear. I have heard of apples taking on hawthorn rootstock.
John S
PDX OR

Lon, how large did your pear trees get on hawthorne rootstock?

Thanks. I don't think they grow here. At least, I've never heard of one.

I might try Mt. Ash, though. We have those.

Lon,
Do you have any ID cues for identifying seedling Douglass hawthorn? Most around here are Washington hawthorn. I've also seen a lot of carriere hawthorn and many others.
Thanks
John S
PDX OR

For the HOS Make-A-Tree we use quince, OHXF 333, OHXF 87 and betulifolia for pears. The bet is used only for the asian pears. Ted Swensen has put together a list of compatible pear varieties for quince understock. The interstem most often used is Comice, not Winter Banana because it is an apple. So far, the most dwarfing rootstock we have found for pears is the OHXF 87. When it first became available, the commercial growers treated it in the same manner as the rootstock they had previously been using. They found more watering was necessary to get them established. I think for backyard orchardists this would not be a problem, we know we have to water our baby trees.

Thanks for responding Joanie,
That's great information. I assume that the quince is now used for quince and the OXHF is for the Euro pears. I happen to have pears on quince and they are nearing their expected incompatibility date.
John S
PDX, OR

Here in the UK almost all nurseries seem to use Quince A and Quince C for retail trees. Pyrodwarf is also sometimes used. Fireblight is not such a big problem here though.