This one goes out to the Cali cherries out there, although in general some of what I say is applicable to all parts of the country.
Yesterday I noticed the first wisps of green escaping from the buds of my Anna/ EinSchiener/ Dorsett apple tree. This moment is called bud break and in most parts of the sountry this happens in spring. Here, of course, if the trees actually waited until Ostara, they'd be in deep kimchee by August with a full load of fruit and 110 degrees out!
So, what exactly is bud break, and why do some trees drop their leaves and grow a whole new set every year?
In most parts of the country, this is absolutely essential to getting through the winder. No apple tree is going to survive a blizzard with all of its leaves. This is why they drop them in fall-- they basically go dormant-- hibernate. The buds are carefully sealed from the elements, and dormant. Giberellins help prevent the bud from sprouting-- breaking. How long the bud stays this way is determined by the amount of gibberellins the tree species and variety produces.
This ;ast sentence is important, especially so for us Cali cherries. An "Anna" apple needs only 200 hours or so of temperatures below 45 degrees to wash enough gibberellin out to induce the break for the year. The next warm spell after those 200 hours, and viola! Spring is here for that tree. This is a great adaptaion for a California apple-- it helps it bear early while the weather is mild. The downside of bud break, howeverm is that once exposed the tissue is then sensitive to frost and cold. This is why you don't see "Anna" grown in Indiana-- they would freeze each year. Conversely, "Arkansas black" would not prosper in southern Cali (excepting the Big Bear, Arrowhead, Julian, Apple valeey, Oak Glen and Idyllwild areas) because it would never get enough chill to induce a good, clean bud break but is fantastic in colder regions, where it will stay safely dormant until spring really gets there.
So now you know. Let's hope California doesn't have any more crazy weather now that the deciduous trees are breaking bud (this holds for peach, nectarine, and almond too, and almonds are a major commercial crop around here) We could have a great crop if the weather stays mild, since the cold snap was actually GOOD for these dormant trees (and grapes too I might add).
I as always love to hear from other gardening Cherries, especially local ones. Don't feel bad if you're new to the good earth, I don't bite. I might even help turn a bit of soil for you.
