North American Fruit Explorers mailing list at ibiblio

[Bill Garthright <billg@inebraska.com>]

How does one delay bloom?  My peach and cherries get frosted out fairly often due to early thaw then freeze in spring.

I love this question. Here are some things I've heard (but I can't really vouch for any of them):

1)  Paint the trunk and main limbs white, so they reflect the sun and won't heat up quite as fast in the spring.

2)  Keep the limbs more horizontal. I don't know if this is true or not, but I've heard that vertical branches are more vigorous and start earlier in the spring.

3)  Keep the air and the ground cold, if possible. Someone here - sorry, but I don't have time right now to track down who it was -  told me about putting barrels around young trees when they're first planted (up north). Then, when it gets cold enough in the winter, keep adding small amounts of water that will freeze into a solid block around the tree.

I'm not sure about that, but a solid mass of ice around or under a tree would be bound to keep it colder than without it, right? Of course, I don't know how long it would last when things warm up. But heavy mulch around a tree might also help. Or put mulch on the ice, to keep it from melting too quickly on warm days?

4)  Last year, I was going to arrange temporary shade to keep the sun off my dwarf apricot trees, at least to some extent. But we had such a late spring that I didn't need it. Still, I suspect that it would work, if I could actually do it (we get a lot of wind here, so I have my doubts that I could really fix up something that wouldn't blow away).

5)  I've heard that late pruning also helps (compared to early pruning, I mean). But when I mentioned that in this group, the idea was pretty well shot down. Well, that's the problem. I hear things, but I have no idea if they're accurate or not.


I will say that I've pretty well given up on trying to protect blooming trees from late freezes. It never works for me, partly because we generally have a lot of wind here, when arctic fronts come down from the north in the spring. And I end up knocking off most of the blooms myself. (If your problem is calm, cold nights, it might work, though.)

But trying to keep problem trees (for me, it's just the apricots) from blooming too early does seem possible, if I try to keep them cooler and shadier than they'd otherwise be. I don't know how big a difference it would really make, though - maybe not much.

And finally, you might plant such trees in a microclimate where they won't start as early in the spring (or, alternately, won't be as susceptible to late frosts).

Bill
Lincoln, NE (zone 5)

http://garthright.blogspot.com/

--
Why not go out on a limb? That's where the fruit is. - Will Rogers