A Gardening Journal
The Best Season Ever: Meyer Lemon in Bloom
- Published: January 30 2017
Meyer lemons are irresistible fruit: their fragrant sweetness makes typical lemons seem coarse. Plus, their thin skins make them tricky to ship, especially outside the peak November to March season—and, therefore, all the more desirable. So why not grow your own? The trees are compact—shrubby, really—and will flower and fruit prolifically even as youngsters.
Below, my little guy in the greenhouse until spring, barely two feet tall but already bursting with blossoms.
The dense clusters of buds appeared sporadically during the summer, but it seems that cooler but still frost-free fall and winter temperatures—I don't heat the greenhouse to warmer than fifty degrees Fahrenheit—are what really encourage bud production.
The waxy four-petaled flowers are highly fragrant, and forecast the delicious fruit to come. But most winter-flowering fruiting plants are at a disadvantage indoors: unless you also keep an indoor beehive, the plants don't have access to essential pollinators. The latin term for insect pollination is entomophily: "entomo" meaning segmented or cut into pieces—hence, insects—and "phil" meaning loved. Insect-pollinated plants, then, are entomophilous.
It's a cruel reality that the only insects you're likely to find in an overwintering greenhouse are pests, not pollinators. In the picture below, look at the green aphids on the lemon flowers' petals. Yikes. I'll deal with the aphids later, but first, to the pollination.
The pistil is ringed with stamens, each of which has a pollen-laden anther at its tip. Although the gap between the anthers and the pistil might be just an eighth of an inch, the pollen can't simply leap across on its own. Worse, because entomophilous plants have evolved to welcome and—therefore—depend on their insect vectors, the pollen they produce is typically large and heavy, to make a more substantial and attractive temptation for the pollinators' foraging. (Plants that rely on wind to carry their pollen typically produce pollen grains that are small and light-weight.) In the still air of the greenhouse, any Meyer lemon pollen that does fall from its anther is likely to tumble downward, not slide sideways onto the pistil.
A small paintbrush is the answer. Pollen clings to its soft bristles, which are so pliable that the brush can be, well, brushed lightly across the top of the entire stamen-pistil group without worry of breakage. There's no need to daub from a specific anther to a specific pistil, whether of a different flower on the same Meyer lemon tree or of a flower on another one: citrus flowers are self-fertile, so any pollen that reaches any pistil is likely to be successful.
Because only a small amount of the pollen adhering to the brush can be dislodged onto any given pistil, the overall affect is that pollen picked up that day from the anthers of the various open flowers is likely to be distributed among all of those flowers' pistils. In the picture below, you can see that grains of pollen—and, I guess, an entire dislodged anther—have come to rest on the surface of a pistil. Hooray: one of the pollen grains is almost certain to penetrate into the pistil and complete pollination.
Citrus typically flower for extended periods; in climates mild enough for these plants to be grown directly in the garden, they can flower year-round. Even in the less-floriferous environment of the cool greenhouse, there are already dozens of buds still to mature to flowers, and new bud clusters will emerge week after week. I now keep the paint brush in my bag so that I can pollinate flowers duing my weekly greenhouse visits.
In the comparatively cool and weak-sunned climate of New England, fruits of Meyer lemons mature slowly. Flowers that are pollinated this winter are not likely to have matured to harvestable fruits until the following fall and winter. If this current hand pollination is successful, I'll be picking lemons as I begin the next pollination season.
Meanwhile, to those aphids! I'll also bring a sprayer of a nature-based pesticide to the greenhouse. Fittingly, an oil extracted from citrus peels is one of its active ingredients.
I'll profile Citrus x meyeri in full soon.