It’s time to prune, and to help you, I’ll be holding a PRUNING WEBINAR on March 29, 7-8:30 EST. Learn the tools of the trade, how plants respond to pruning, details for pruning various plants, and enjoy a fun finale on an easy espalier. There’ll be time for questions also. Cost is $35 and you can register with Paypal or credit card here.

Choice Syrups

I’ve given up on maple syrup this year. The tree I tapped was too small to yield anything significant. 

I’d almost given up on river birch syrup. I thought perhaps it was the timing — and, have since learned, that it is! Sap from any one of a number of birch species doesn’t begin to flow until temperatures are consistently 50°F or higher, which arrives near the end of the maple tapping season and continues until about the time the trees leaf out.

River birch, tapped

River birch, tapped

Black walnut was another possibility for tapping. I previously had pooh-poohed it because, much as I love this tree’s nuts, I imagined the aroma of the leaves or the hulls oozing its way into the sap. Ugh!

Another reader reported that walnut syrup is delicious and I should try it, so I did. Sap started dripping as soon as I drilled the holes. The first batch is boiled down, and it is delicious. Not that different from maple syrup, with just a slightly different, smoother flavor. Nothing reminiscent of the nuts, leaves, or husks, though.

Black walnut tree, tapped

Black walnut tree, tapped

Processing was via the same low-tech approach I’ve used for maple syrup, merely adding each day’s “catch” to a big stock pot sitting on the wood stove. The woodstove is stoked pretty much continuously this time of year, so the sap is always evaporating, with the added bonus of humidifying the house.

I see a few eyebrows going up. Sticky walls and ceiling are what comes to some minds upon the mention of cooking down maple sap indoors. Well, that’s usually myth. Sticky walls and ceiling only result when the sap is in an active boil and bubbles bursting on the surface of the liquid send little droplets of sugar water into the air and onto walls and ceilings.

Until the final stage of my sap-making, the sap is just slowly evaporating. The vapor given off by slowly evaporating, simmering, or boiling a solution of any sugar and water is nothing more than water vapor. That’s why the maple (or black walnut) sugars become concentrated in the remaining liquid. They stay in the pot.

In those final stages of concentration, with much reduced liquid volume, the liquid can indeed reach an active boil. The pot of liquid announces that it’s nearing that stage by starting to gurgle like a baby, at which point it needs to be watched closely, mostly so that the syrup doesn’t get too concentrated or burn. The finish point is when the temperature of the liquid reaches about 219 degrees F. 
Boiling sap
I discovered a big difference from maple syruping when I attempted to strain off schmutz in the boiled down black walnut sap. The schmutz was a jelly that quickly clogged up the strainer. The amount of schmutz can vary from tree to tree, with time of year, and who knows what else. Turns out that black walnut sap is high in pectin, aka schmutz. Perhaps calling it “black walnut jelly” would make it more appetizing. Black walnut syrup

Too Late to Prune, Say the Squirrels?

Someone wrote me that squirrels were chewing on a Norway maple last week and the sap was seen dripping down, then went on to ask if that meant it was too late to prune. Perhaps the squirrels were enjoying some of the sweet sap.

Yes, you can tap and boil into syrup the sap of all kinds of maples; I’ve tapped and made syrup from silver maple, red maple, boxelder, and, of course, sugar maple. And each tastes slightly different from the other.

Getting back the pruning… It’s not at all too late. It’s fine to “dormant” prune any plants up until the time when they unfurl their leaves in spring. Actually, peach trees are best pruned when they are blooming.

Another good question might be: Why not just cut the Norway maple down to the ground? The trees are invasive and displacing our sugar maples, they have poor fall color, and they create lugubrious shade beneath which grass and much else can’t grow. Mostly, people keep these trees because they are already in place and full grown.


  1. Jon Frank
    Posted March 18, 2021 at 10:48 am | Permalink


    Thanks for sharing this informative article. I learned some valuable info about the trees you mentioned. So how did you strain out the Black Walnut Syrup?

    Blessings on your spring,

    Jon Frank

    • Posted March 18, 2021 at 8:12 pm | Permalink

      I’m not making that much syrup, this year at least. I just put it through a fine metal strainer that I had and then kept moving it around with the round edge of a soup spoon. That got most of the liquid part through the strainer. I’m also trying dipping a small strainer into the simmering sap while it’s still pretty thin. This should get out some of the gel early on and the thinner liquid will move through the strainer more easily.

  2. Michael Grubic
    Posted March 18, 2021 at 11:07 am | Permalink

    I’m trying to register for the pruning class. The link only goes to PayPal. How can I register with a credit card?

    • Posted March 18, 2021 at 8:08 pm | Permalink

      You can pay with your credit card at the Paypal link. Let me know again if you have trouble with this.

    • Jim B
      Posted March 19, 2021 at 9:19 am | Permalink

      Whenever a place uses the Paypal system for payment, you can also just use a credit card there without signing up for Paypal. In that case, Paypal is only used as the intermediate agent that that collects the information and pays the vendor. No need to establish a Paypal account to pay this way. If you find you are doing this a lot, then it might make sense to establish your own Paypal account (which links to a credit card or a bank account instead if you like). You don’t need to do that, though.

  3. Jim B
    Posted March 19, 2021 at 9:12 am | Permalink

    Glad you took my advice and tried the black walnut! It looks like yours came out fine! Yes, I should have warned you about the pectin, which is a minor issue which (I think) one doesn’t have with maple. With a large spoon, I just skim the foam off the top, by dragging it up against the wall of the pot. If you do that a few times early in the process, you’ll have no schmutz left at the end when you want to strain.

    Although I was going to skip it this year, your post motivated me. I did wind up tapping a handful of black walnuts and getting about 15 gallons of sap, which ought to yield 3 pints of syrup or so. I’m in the middle of processing now and it’s coming out nicely.

    • Posted March 21, 2021 at 8:34 pm | Permalink

      Thanks again for coaxing me to try the black walnut syrup. I also started skimming the foam to reduce the amount of gel. You’re right: it’s not that big a problem, especially on the small scale on which I am doiing it.

  4. Maria Reidelbach
    Posted March 20, 2021 at 10:08 am | Permalink

    Thanks for the great, first hand info, Lee!

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