Three large Autumn Olive bushes (Central Ohio) bloomed and then froze,
which I'd expect would prevent any fruit from forming.

Instead it seems so far to have prevented any but a very few isolated
leaves from sprouting, in addition. It looks like a bare year, at
least.

Is there some mechanism that kills the whole plant in a freeze?

Like is it using water as sap, or something?
--
Ron Hardin


On the internet, nobody knows you're a jerk.

In article ,
Ron Hardin wrote:
Three large Autumn Olive bushes (Central Ohio) bloomed and then froze,
which I'd expect would prevent any fruit from forming.

Instead it seems so far to have prevented any but a very few isolated
leaves from sprouting, in addition. It looks like a bare year, at
least.

Flower buds are usually more frost-sensitive than leaf buds, but if
it gets cold enough, the leaf buds will freeze, too.

If the branches themselves weren't killed, the plants will probably
put out leaves later in the season, and recover over the next
year or two. If the bushes froze to the ground, they may come back
from the roots.

You can tell if the wood is alive by scratching the bark with a
thumbnail. If it's alive, there will be moist green tissue under
the bark. If it's dead, it will be brown and dry, and you might as
well prune it back to live wood.

Is there some mechanism that kills the whole plant in a freeze?

Like is it using water as sap, or something?

Plants have several mechanisms of increasing their frost resistance
when they go dormant in the fall. Most importantly, they reduce the
water content or increase the solute content in their tissues (or
both). When they break dormancy in the spring, they restore that
water content and become susceptible to freezing damage again.

Plants that come from cold continental climates "assume" that if it
warms up, it's going to stay warmed up, and tend to suffer the worst
in climates that have warm periods followed by more cold. Apricots
and walnuts are particularly hard-hit in this kind of weather because
they bloom early, but most plants are susceptible to such damage in
unusual years.

We had a fairly normal winter, maybe a bit milder than usual, here
in southern Ontario, but we had a big warm spell in March, followed
by significant cold. My Rosa rugosa froze to the ground, which
amazed me -- these things originate in Siberia and are hardy on the
Canadian prairies! But when I looked at the dead wood carefully,
I could see that the buds had started to develop before they and
the wood froze. Fortunately, it's on its own roots and is coming
back from them quite well, so maybe I'll have some roses next year.