Dear Garden Guy… What??? (Part Two)

As I wrote in the last post, the Facebook listing from a local garden center has really gotten me thinking. Here’s the post once again: If your veggie plants are flowering but not producing, Garden Guy suggests squeezing each blossom gently to knock some pollen onto the stamen of the flower to pollinate it. Below this post was a picture of a summer squash plant.

While the misuse of the word stamen was easy to understand, the central message of this post has me confused. Squeezing flowers to pollinate them might work with some plants but it’ll never work on a squash plant because of the kind of flowers that it bears.

The vast majority of plants bear flowers that are perfect. This term has nothing to do with aesthetics; perfect in this case is all about functionality. A perfect flower is one that has a functional stamen and a functional pistil. In other words, it has both the male and female organs. Some perfect flowers are morning glories, roses, peas, beans and tomatoes. However, not all plants have perfect flowers; some have separate female (pistil only) and male (stamen only) flowers.

In some plants these male and female flowers are on separate plants. One plant will produce only female flowers while another plant will produce only male flowers. These plants are called dioecious. An example of this is the holly plant. Only a female holly plant will produce red berries; the male plant only produces pollen.

Zucchini Flowers -  Male on Left Female on Right

Zucchini Flowers –
Male on Left
Female on Right

Other plants are called monoecious. These plants have separate female and male flowers but they’re both on the same plant. The cucurbits (squash, gourds, pumpkins and melons) are generally monoecious. It’s easy to tell which are the male and female flowers in these plants. The male flowers grow on a stalk (peduncle) while the female flowers have at their base a small fruit.

With this background I can now address the Garden Guy’s suggestion. If you’re going to squeeze a flower to pollinate it, that flower has to be perfect – it has to have male and female organs. A gentle squeeze would likely knock some pollen from the stamen onto the stigma of the pistil in a bean or tomato flower. But I’ve never had a problem with either of these plants being pollinated. Between insects and the shaking of the flowers caused by the wind, pollination happens naturally.

Pollen Covered Bee Leaving a Male Squash Flower

Pollen-Covered Bee Leaving a Male Squash Flower

In the case of squash, the female flowers are pollinated by insects. A bee visits a male flower and gets covers with pollen. It then lands on the female flowers and some of the pollen rubs off onto the stigma of the pistil and voilà, the squash in pollinated.

But if there aren’t bees in the garden to pollinate the squash, you can squeeze those blossoms forever and nothing is going to happen. If you squeeze a male flower you’ll put pollen all over the inside of the blossom but there’s no pistil to receive the pollen. Squeezing a female flower won’t do anything either since there’s no pollen in that blossom. If you’re squeezing flowers you might end up with enough pollen on your hands to inadvertently pollinate a female flower but if you do, it’s just luck that it happened. The squeezing didn’t do a thing.

zucstigma copyIf insects aren’t pollination your squash, forget squeezing. Instead, in the morning pick a male flower, tear off the fused petals and then rub the exposed stamens onto the pistil of the female flowers. Or take a small paint brush and collect some pollen from the male flowers and then brush the pollen onto the stigma of the female flower.

Gently squeezing a flower will only pollinate it if and only if the flower is perfect. If the picture attached to the Facebook post had been of a tomato plant, I wouldn’t have been so confused. But when squeezing flowers is linked to a monoecious plant like summer squash, it make no sense.

In my garden, insects and wind pollinate all of the perfect flowers and the bees do a great job on the cucurbits. But if the squash aren’t being pollinated, I won’t be squeezing anything. I’ll be taking a male flower and brushing it against the female flowers in order to pollinate them. That’s the only sure way to make pollination happen.

As far as the Garden Guy, I’ll keep reading his posts; I pick up tips and ideas from many of them. And even when there’s a post with which I disagree – like this one – it gives me things to think about and explore. Thanks to this post I reacquainted myself with flower morphology, perfect flowers and dioecious and monoecious plants. So thanks for the post, Garden Guy!

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