Monday, May 9, 2016

Which is the Strawberry?

I am adding a number of Virginia strawberries, Fragaria virginiana, to my gardens this year.  This is part of my plan to incorporate more edible plants, particularly natives, into the landscape.  While I may not get many berries from these little plants this year, I expect to get a harvest next year after the plants have settled in.  One important thing that I will need to learn is how to tell these fruit bearing plants from the insidious mock or Indian strawberry, Duchesnea indica, that is growing just about everywhere on the property.

Here is mock strawberry with its bright yellow flower
and trifoliate leaves.  These leaves are evergreen here in zone 6.

Indian strawberry is an exotic species from southern Asia imported to the US as an ornamental plant and has widely naturalized over the years.  The 'Indian' in the name refers to a region of Asia, not Native Americans.

Both plants have similar trifoliate leaves with bluntly serrated (toothed) edges.  They each form tight clumps of basal leaves, spreading by above ground runners.  Also, they each produce bright red fruits with seeds on the surface.  The most obvious difference is the flower color, Virginia strawberries have white, 5-petaled flowers, while those of mock strawberry are bright yellow.

This newly planted Virginia strawberry has not settled in enough to flower.
The leaves are persistent through the winter, but these will turn red,
adding to winter interest.

Another difference is in the fruit.  The seeds of Virginia strawberry are located in depressions on the surface of the red 'berry'.  Mock strawberry seeds are actually in projections above the fruit's surface.  Also the fruit from mock strawberry is dry and tasteless compared to the sweet, juicy fruit from the Virginia strawberry.

These differences make it easy to tell the two plants apart when they are in bloom or fruit, but what about the rest of the year.  I was looking for a definitive feature to rely on.  Many times botanical descriptions depend on doing a comparison, e.g. more or less hairy, or 'broader' leaf.  I was looking for a yes or no test that I can use quickly while pulling weeds.

Here are both surfaces of the leaves of mock strawberry.
The arrow at left points out the longger terminal tooth.
So while the leaves of mock strawberry are more coarsely serrate and its veins are more divided than those of Virginia strawberry, the more practical method for me is to look at the tip of the leaf.  On nearly every leaflet of mock strawberry the  terminal tooth is longer than the ones on either side.  For Virginia strawberry the terminal tooth is shorter the its neighbors.  Maybe after working with the Virginia strawberries for a season or two I will appreciate the finer differences.  For now the goal is to not pull up any of my new plants.

Here are both leaf surfaces of Virginia strawberry.  Again,
the arrow points to the terminal tooth on the leaf, which is
distinctly smaller than its nearest neighbors.