Backyard Biology

Nature stories from my backyard and beyond

Nature Stories

Raining Violets

Tuesday, June 10, 2014


It is one of those days when there is a song playing in my head and it just won’t quit. I don’t really mind, though. I’ve been singing the song softly to myself all day. These are the words to the song:

When April showers may come your way
They bring the flowers that bloom in May
So when it’s raining have no regrets
Because it isn’t raining rain you know
Its raining violets

I have been singing this song because today, the middle of May, my yard is covered with violets, more violets that I ever remember seeing. violet fieldIt got me to wondering if there is any truth in the song. Does rain in April really bring the violets in May. Does a rainier April mean more violets and a drier April fewer violets? If so, then judging by the amount of violets in my yard, this past April should have been the wettest in the 22 years that I have lived here.
Time to do some research.

The weather data I need can be found on the NOAA National Climate Data Center. It allows me to call up the average rainfall in the Boston area since 1885. More than enough data for me. The results are:
The average rainfall in Boston for April is 3.60 inches. The rainfall for this past April was 2.88 inches, making it the 9th driest in the last 22 years. Clearly, the amount of rain does not directly influence the success of the violets.

Violets don’t need April showers to show up in ones back yard. What they need is just to get their foot in the door. If just a few violets become established in the lawn, chances are there will soon be lots of violets. Many violets, including the Common Blue Violet that I am walking among, have a number of ways of propagating. The most obvious way is by insect pollination. A flower as showy as the violet is designed to attract insects. When an insect lands on a violet, it sticks its head in the flower to get at the nectar. While doing this, it also gets some pollen stuck on its body. When it visits another violet, the pollen rubs up against the pistil, or female part of the flower. This pollen will fertilize the egg and produce the seeds. So far so good. But if you watch a patch of violets for any length of time, you will notice that while they may attract an insect or two, they are not attracting as many as other flowers. Therefore they need a backup plan.

Later in the summer or early fall, many violets, including my Common Blue Violet, will produce a second type of flower. This flower does not make showy petals, nor does it produce nectar. In fact the flower never opens up. Both male and female parts are contained within the flower and the plant pollinates itself. This backup plan insures that even if the violet is not pollinated by an insect, it will still produce seeds.

blue violetOnce the seeds are produced, they need to be spread around. Simply dropping from the plant and growing alongside the parent violet will not do. The violet fruit may burrow its way underground before emerging some distance from the plant. Once the fruit ripens in the fall, it explodes open. The seeds can be be propelled up to a foot away. They may germinate where they land, or they may be picked up by an ant and carried down into the nest. The ants will eat the soft protein-rich outer seed covering, called the elaisome, and discard the harder inner seed in the nest’s detritus chamber. Here, where the growing conditions are ideal, the seed will germinate.
Once the violet has established itself at some distance from its parent, it will form a rhizome, an underground root storage system. This allows the violet to store nutrients that might be needed during harsh conditions, like the continual mowing of a lawn.

So it seems that the violets don’t need the April showers to bloom in May. They are well equipped to do so on their own. In fact, they are such good breeders that once established, they may take over a lawn. For that reason, some people consider them a weed. Not me. I enjoy them for their beauty. They are much prettier than the flowers of the grass. Besides, they serve another function. They bring the butterflies that bloom in June. Violets are the food source for the larvae of the fritillary butterflies. With my crop of violets this May, I am expecting a plethora of fritillaries this June.