If you are a backyard grower like most of us, you might plant just one pecan tree and think that will be enough to produce nuts, but you should of think again. One tree is not sufficient for pecans; in fact, it doesn’t work at all the way it does for peach or apple. And no, this isn’t about watering or soil quality. This is timing.
Pecan trees are what’s called dichogamous: Both male and female flowers appears on the same tree, but they mature at separate times. What happens if your tree pollinates itself before its own flower have matured? You’re looking at a beautiful landscape specimen that yields precious little…unless you have a partner.
Why You Need Two Pecan Trees for Good Pollination
If we break these down into two groups on the chart above, one is the protandrous variety, which we call Type I; they open their male flowers early in the spring, before females even begin to bloom. Then there are those that open their females first, waiting for their pollen to ripen once neighbors open theirs (the protogynous ones, known as Type II). And neither is sufficient on its own.
The graphic emphasizes certain pairings… Desirable with Stuart, for instance, or Cheyenne with Elliot. Those aren’t random matches; they’re calculated overlap. One person’s pollen release match the other’s ready period exactly.
Plant two Type I trees side by side and you’ll have lots of airborne dust, no nuts to speak of, because both trees will want to give not receive at the same time. You must balance the ratio to make sure that each female flower is near some pollen source when she bloom.
The matchmaker in this case is the wind. Insects are not involved at all; pecans depend totally on air transport. Billions of tiny seeds is cast into the breezes from each catkin, each with more than a thousand flowers in them. And quantity makes a difference: Most pollen goes astray. As the info graphic points out, “pollen may be carried as far as 150 feet.”
That’s how you know what distance separates you from a partner, or determines your planting range. Also think about wind direction when planning rows: Planting the trees at right angles to the common spring winds will carry that treasure farther through the orchard instead of confining it to a static patch of air.
The most important variable in all of this is the weather. Nature will always have its say and that is particularly true for that narrow opening when pollination occur. If the day is very hot (above ninety-five degrees), pollen dries out nearly immediately; if it’s too cold (below twenty-eight degrees F), a late-spring frost can kill off those precious buds before their catkins even unfurl. And then there’s the effect of heavy rainfall, which washes pollen from the air, or just simply crushes the pollen sacs by clogging the sticky female flowers called stigmas.
All these conditions go some way toward explaining why yield vary so significantly from year to year. Sometimes it’s not even the fault of the tree; sometimes it’s simply a matter of getting all the right conditions at the right time within those precious few weeks in May.
All of this adds up to thinking like an orchard when managing them. Trees with more airflow are better, so open canopy pruning help the wind move deeper into the tree. Make sure trees gets enough water throughout the bloom period. This prevents them from becoming stressed. Stress can reduce the time they are ready to pollinate female flower. You can pick out varieties that is resistant to disease in your particular climate zone.
This is one thing you have no control over, but you can prepare yourself for it! The idea is to have some backup. That way, even if rain or frost causes one pairing to be a dud, there’s still another combination that yields a working fruit.
In short, growing pecans isn’t so much a test of raw strength as it is a matter of timing. As with all things, there’s half of the equation (the one you planted this past year). There is also looking around to see what other trees are nearby and where the prevailing winds blow. You have to wonder how the heck the tree knows exactly when to bloom, and then you try to honor that picky schedule yourself.
If all goes right, you’re not left with a handful or two of nuts but great big balls of shelled goodness waiting to be picked. And that’s no accident. Because thinking of pollination as a solo performance misses the point. It’s a collaboration.