I've saved fruit many times from temps as low as 25/26/27 by going out in the very early morning hours between 4:00 AM and 6:00 AM and spraying them down with water. It does help. A couple of things -- 1) bring the hoses inside somewhere they can't freeze. Even a little water will leave an ice plug in the hose, which is frustrating and problematic at 4:00 in the morning. 2) Be sure to wear heavy, waterproof gloves with insulated gloves inside. Your hands will get cold fast, especially when wet. 3) Always get dressed. Don't go out in your pajamas and an overcoat like I did, then hide behind the compost pile for 20 minutes while the cops shine your yard looking for burglars because some neighbor called the police about the strange goings-on in your yard at 4:00 in the morning! :=)

One easy trick I stumbled upon was to build the simple teepee with wire or tomato cages or anything you have on hand and then drape a tarp (plastic or fabricc)over the teepee and extend it out in all directions away from the plant. If you have bushes or small trees in a row and really big tarp just drape it up and over what you can and then lay the rest of it flat against the ground. The soil will give off heat at night and the heat will collect in the tents made by the small trees. There can still be some frost damage where the leaves touch the plastic but it is amazing how much green you can save.

I'm really late with this reply, but maybe it will help you next year. I keep Christmas tree lights in my fruit trees. The kind with the large bulb; the fairy lights won't help. I have the lights on a thermostat, to go on automatically when temps get down to 40 degrees. It's not a huge help, but I figure it gives me a couple of degrees more leeway, and that's often just enough. Blossoms won't normally get damaged until about 29 degrees, so if I can protect them to 26, it covers almost any spring freeze we have. If you only have 1 of each type of fruit, your problem might be lack of pollination rather than frost. 100% probability that the plum problem is lack of a pollinator. I'm supposed to be zone 5, but that's a joke. Weather is much tougher than zone 5. I'm getting fruit, so I can't see why it would be too cold in zone 7. It's May 5th and there is snow and hail going on outside my window right now. I plant cold hardy varieties and get the latest bloomers I can find. Late blooming will make a huge difference in whether or not you get fruit where there are spring freezes. I suspect I lost the crop on my earlier blooming apricot. We had several night with temps in the teens right after it bloomed. But the apricot that blooms 2 weeks later has lots of tiny baby apricots on it right now.

Hi Leon:I am not using the boat ,anymore because,I can't launch it,to water,after I had Back Surgery,in 2006. But I used it before and had good fun,going fishing on Delaware river tributaries. As for the pruning,I really used the tree to get some extra Money. I sold all those cuttings,on Ebay,and,I am sure whoever grows it will be very Happy with the results. I know I am. Best Regards