Rain and Needle Size…

You may have noticed that some years we have much longer needles on our pines than other years. Why? We haven’t done anything differently…

But the weather has.

Those years have unseasonably high springtime rainfall. And what is water to a plant? Food. (Water + CO2 + Light = Dinner)

This White Pine is showing needles twice as long as the year before, the result of a lot of rain in the spring. And being mid-May they will continue to get longer yet…

More water equals more food, and more food results in more plant tissue. Longer needles…longer internodes…larger leaves…longer petioles… Bigger elements. And there’s not a lot we can do about that out on the open benches. But the good news is that larger foliage will bring more buds. Then when drier springs cycle through again, we can program our watering to water only when the trees are drying out, and be able to reduce the size of our foliage, too.

Needle length does give us a tip, too, about our watering in the spring. If we consistently get long, sappy looking needles, maybe we’re not waiting for the soil to dry out. Maybe we’re watering by rote, not looking, only going through the motions. Better: Look, think, then water. Or don’t water.

6 Comments

  1. Frans says:

    Hi Michael,
    Could it be that with increased rain you get more desolved nitrogen (most water soluble element) and from there the increased needle length. We know that nitrogen promotes leaf,needle growth.

    • crataegus says:

      Increased water will enhance all chemical processes. But the white pine pictured has not been fertilized this spring. I fertilize after growth stops with the white pines, specifically to reduce needle size as much as I can. But with high rainfall springs…not much we can do.

      • frans says:

        What I am getting to is the possibility of nitrogen dissolved in the rainwater as it falls through the air and therefore the fertilizing effect. I see it clearly in my Wild Olives- growth spurts after good rains.
        Just a thought?

  2. Mac McAtee says:

    I keep my pines and juniper on a bench that has a clear plastic roof. They only get watered when I want them to. Here in the Piedmont of North Carolina we can go two weeks in the spring where it rains every day. Yesterday we had 5/8″ of rain. So far today, it’s 6PM here we have had 3 1/2″ and it is going to keep coming for the next three days. Covered benches is my only defense.

  3. David Wheeler says:

    thank you for the reminder – Dave

    On Tue, May 23, 2017 at 8:42 AM, Michael Hagedorn wrote:

    > crataegus posted: “You may have noticed that some years we have much > longer needles on our pines than other years. Why? We haven’t done anything > differently… But the weather has. Those years have unseasonably high > springtime rainfall. And what is water to a plant? F” >

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