It depends on how cold it gets. But before full bloom it takes a really cold temperature to kill everything. After the crop is set a moderate freeze can take nearly everything. But in my experience, and I've see dozens of damaging freezes, one freeze usually doesn't take 100%. Often 90-95%, but seldom 100% in one event. Unfortunately in Texas it's not unusual to have two or three damaging freezes in one spring. Most places where people try to grow fruit have one freeze once in a while.

This yr we've had two freezes that have hurt my nectarines. The pears are blooming and apples are 10-14 days away from bloom. the last 5 yrs we've had damaging freezes in April. Last yr April 27, two months after things started blooming.

The Fruitnut

Keepitlow:

We all live in horror of the classic freeze in mid to late April that takes 90% of the apricots, many plums, and even some peaches. 2007 was such a year in the mid-South and Atlantic areas, which includes me. At this time of year I am constantly reviewing the long-range forecasts, which, unfortunately, only go out 10 days. And even those are not guaranteed. So far, this year looks to be a nice, slow warmup, and the colder than normal winter has actually resulted in some delay of early bloom on apricots and plums, which have often been near 1/2 bloom at this time of year. Right now, my apricots are mainly at the popcorn stage, with only a few blossoms fully open. I am guardedly optimistic.

If your trees have lots of blooms, you will get some fruit even with a hard, late freeze, just as the Fruitnut says. I am surprised that his nectarines and pears are blooming; either his zone 7 is little different than mine, or average winter temps in TX have been warmer than Virginia.

Don Yellman, Great Falls, VA

Don: We have already had 40 days this yr in the 70s and 80s. That's an exact count, not a guess. Yet our ave last frost date is about the same as yours. That is why we have way more frost damage than you do. But I sure do appreciate our near absence of serious insect and disease problems.

The Fruitnut

Fruitnut, how did you do the year of the April 27 freeze with your crops?

Don, is there much that can be done with weather forecasts that can help one protect the trees? I have some row cover, but I guess it is hard putting it over big trees. (Although mine are small trees.)

As far as the popcorn stage, does frost hurt those buds or is it only open flowers and fruit that gets messed up?

It is not only the low temperature, but how long it stays there that determines the extent of the damage. This year we had a warm January but a February in which the temperature fell rapidly at sundown giving a much longer period of freezing. I lost plants that went through lower temperatures the last two or three years with no damage. Al

I have this bookmarked from another thread. Good pics and temperature threashholds throughout flowering.

Here is a link that might be useful: Illustrated Spring Frost Damage Thresholds

Keepitlow -- frosts/freezes can be a real bummer. You definitely can lose an entire crop to the cold, especially on stone fruits (pears and apples seem a little tougher when it comes to surviving the weather).

I have had quite a bit of success against cold as low as 27/28 degrees by hosing off the trees several times during the night. It really does seem to make an ice coating which helps a lot. I did this last year on April 26th and April 27th when most of my stone fruits and pears were in full bloom, and apples were just coming into full bloom. It dropped down to about 28 degrees the first night, and 30 the second night. I saved a very bumper crop of fruit this way, or at least, I believe I did. Perhaps they would have made it anyway without my intervention, I have no way of knowing, but I do know that I got a fantastic yield of fruit last year, despite those two hard freezing nights at just the wrong time.

It's cold, hard work getting out there in the middle of a freezing night and hosing down the plants, but worth it IMO. One lesson I learned many years ago -- do NOT go out in the backyard in your pajamas and an overcoat with no ID to do this, especially if some well-meaning but confused neighbor is going to call the cops because something unusual is going on in someone's back yard. This actually happened to me -- the cops spent 10 minutes shining their spotlights through my yard while I hid behind my mulch pile in fear of embarrasment and/or getting handcuffed and frisked. Lesson learned -- get dressed and carry your ID just in case.

That, and take plenty of replacement gloves, since they'll get wet no matter how careful you try to be. If you're going to go out several times, be sure to DRAIN the hose and take it inside with you between trips -- it's amazing how quickly a hose full of water can freeze solid on a 30 degree night.

Now that's dedication!