I did a search here and didn’t find what I was looking for.
I know folks have grafted pear scions to hawthorns successfully (not sure about long term). What I’d like to know is if there are certain pear cultivars that are more likely to be successful than others?
I think the hawthorns I’d like to graft are downy hawthorns, but I am not 100% sure. I’ve got at least two-three different species of hawthorns here. Those that I’m targeting to graft pears to are some of the larger specimens I have.
Are hawthorn compatible with apple? I was thinking so, what about a winter banana apple interstem, or is the point to see if pears can be grafted onto hawthorn with no interstem
I never updated that thread with my results. I grafted 2 kinds of quince and some medlar onto the hawthorn, at least 2 sticks of each, and all took. It’s only been a year so far, so I can’t speak to long-term compatibility, and the quince does seem to be growing wider than the host, but those medlar bore the same year, so it was at least a partial success.
I’ll probably try pear this year just to see.
Will you try to use the quince as an interstem
I tried grafting 2 different asian pears, and 3 euro pears onto my wild hawthorn last year. 1 euro and 1 asian pear “kind of” took. The graft union was really gnarly and they both ended up dying after 6 weeks.
I was just going to graft it directly. I’ve got enough Callery pears in my backyard for the real grafting work; this is purely a curiosity project.
But now that you mention it I may try the interstem, too, just to satisfy even more curiosity.
I have Hosui on a hawthorn with Old Home as an interstem. It is extremely dwarfed, although the soil is poor hardpan and it didn’t get watered well for many years. It persists, about 10 years on.
There’s an old thread about using Serviceberry as a rootstock for Pear. Do a search for “pear on serviceberry” and it should come up. There were a couple people on there that were interested in grafting onto Hawthorne.
…and here I figured this group had all the answers 
Guess I’ll try a few pear cultivars on a few hawthorns and see what happens. If none of them take, I’ll cut the hawthorns down and plant a pear or apple in that spot next year.
I grafted a couple of pears onto cockspur hawthorn understocks back around 2000-2001… removed one several years ago when making some changes in the orchard, but it was fine, albeit very dwarfed. The other one is still there… probably 8 ft tall now, and very ‘columnar’ in habit… it’s out of the way, so I don’t necessarily notice when it bear fruit, but I know it has done so…
On our local pomology group one person has very succesfully grafted (some) pear on Sorbus aucuparia, that grows like weed on every place here in Finland. Apparently that allows you to grow pear on more challenging soils. And they produce also. We don’t have that many hawthorns native here, although as a hedge we have plenty of Crataegus grayana. So two test subjects for coming spring 
Update on my hawthorn grafts from last year, now that the rootstock/tree has woken up:
Medlar has woken up and looks quite happy. Maybe I’ll get fruit again off it, which would be nice.
None of the quince grafts have woken up yet, and I’m starting to get concerned. They grew fine last year, but maybe there’s some incompatibility that only manifests in dormancy. But it’s still early; hope is not lost.
I had 2 of my 2 year old quince die that I grafted to pears due to incompatability.
How did they die? Did they simply fail to wake up, or was there a noticeable decline?
Hawthorn is the best rootstock for medlar. They are closely related. In fact some botanists consider medlar as part of Crataegus. One of my medlars bought in one austrian nursery is grafted onto quince…it also grows very well i.e. hawthorn - medlar - quince = no problem with grafting compatibility.
My pear on hawthorn died over the winter . Not trying again since I have 25 pear rootstocks now .
Update: None of the 4 quince woke up from their summer sleep. All had taken nicely and grown in their first season, so I’m going to call this delayed incompatibility. No quince on hawthorn.
The medlar did wake up, and is happily sprouting many flowers. Medlar on hawthorn is looking like a winner to me.
I topworked a few hawthorns with 3 different varieties (Beireschmitt, Southworth, and Tyson) of pear scions last week. I’m not super optimistic on experiencing success, but it will be interesting to see what happens.
Didn’t I read somewhere that Pear on hawthorn only survives if some hawthorn branches are kept below the graft.
You may have read that, but it’s not true.