The Birds and The Bees of Cucurbit Flowers

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I just love this time of year with all the beautiful flowers blooming their little hearts out.  Every morning and every evening, I like to take a stroll through my vegetable garden looking for insects both good and bad, pulling the occasional weed and scouting for any diseases.  This week on my morning strolls I noticed that my zucchini, summer squash, fall squash, pumpkins and cucumbers are starting to blossom.  I know this seems late as many of you have probably already had zucchini and cucumbers, but I didn’t get my garden planted until the 2nd week of June.

Female Squash Blossom


Male Squash Blossom


The male flowers bloom first and fall off the plant.  Then a week or so later both male and female flowers will bloom.  Male flowers are on long skinny stems called peduncles and at the base of the female flower is a swollen ovary or fruit.  It is important to have insect activity during the bloom time.  The blossoms stay open for about 4 hours and if they do not get pollinated in the time frame that they are open they will not produce a fruit or it will be misshapen do to lack of pollination.

These plants can be hand pollinated with a small paint brush if there is a lack of pollinators. 


Male flower on the peduncle and female flower with swollen zucchini ovary/fruit


Cucumber female blossom with swollen ovary/fruit

Male cucumber flower

Male cucumber flower notice the peduncle supporting the flower


Other conditions can cause a plant to not produce fruit.  If it’s to hot only male flowers will be produced and female flowers will be delayed.  Drought stress can cause female flowers to abort.  Heat, drought and too much water can cause the flowers to wilt and die.  In these instances, the pollinators are not able to transfer pollen from plant to plant.

High nitrogen levels can also delay female flower production causing fruits not to mature in time.


Female Blossom


Female pumpkin blossom with swollen ovary/fruit.



Pollinators working on the female blossom


Cucurbits can be pollinated by any insect pollinator, but they are most often pollinated by bumblebees and squash bees which forage in the morning while the flowers are open.

Information for this alert was take from the following resources: