On Thu, 23 Jul 2015 09:37:12 +0100, "Bob Hobden"
wrote:

"Emery Davis" wrote

Bob Hobden wrote:

Do you know what they use a stock for the grafting?

I do. It's not a happy answer.

There is no standard understock in the business, as in a clone produce
from tissue culture or some other method. In part the reason for this is
no doubt because cuttings are hard to root, but also because certain
cultivars, or examples of the species, produce prolific seed with close
to 100% germination rates. 'Sango kaku' in one such and is often used as
a seed source. Reputable producers graft red cultivars to red understock
seedlings which produces stronger red colour from the scions.

The problem is that Acer palmatum seedlings are extremely polymorphic.
So the understock may be anywhere from a weak dwarf (or a healthy dwarf)
for a very vigorous plant. This obviously effects the top, so that you
have only an approximate idea of how individual cultivars will perform.

Further, the seed-grown understock varies widely in hardiness. So even a
hardier cultivar like 'Eddisbury' is vulnerable because the understock is
less hardy. (This happened to me where the understock died of cold, while
the top was fine).

But the worst is this. Understock producers (and many grafters make
there own) grow thousands of seedlings year after year in the same soil.
Over time the soil becomes infected with verticillium, and so do the
seedlings. These are coddled along at the producer and then at the
nursery, with essentially perfect conditions. But as soon as they get
home to the consumer, they get stressed, which encourages the wilt.

Many of these plants will only live for 2-3 years at the consumer's home.



I wonder what would happen using a Sycamore (Acer pseudoplatanus) seedling
as the rootstock?

The garden next door to me has a huge Acer that looks like a Sycamore
with red leaves. There are a lot of seedlings growing in both our
gardens that have normal green leaves. I've not seen any mature
Sycamore trees in the area.

Steve

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