Two Mulleins

This picture shows two closely-related wildflowers growing near each other in Pennypack Preserve.  Both are mulleins.  The tall stalk-like plant on the left is common mullein (Verbascum thapsus) and the spindly flower on the right is moth mullein (Verbascum blattaria).  Both are non-native plants originating in Eurasia.  Prior to the European colonization of America, the Eastern US was predominately a broadleaf forest habitat, so there are not many meadow flowers native to the Eastern US.  Most, but not all, meadow flowers in Pennypack Preserve are non-native.  Common mullein and moth mullein have been naturalized in the US for close to 200 years.  It is an interesting question how long a plant needs to be established here before we stop calling it invasive. 

Both mulleins are biennials.  Since they bloom in mid-summer, they need to produce tall, showy flower stalks to get the flowers above the grass to attract pollinators.  This is energy-intensive, but biennials have adapted to this in a unique way.  The first year after germination, the mullein produces a rosette of leaves which lies flat to the ground, but does not produce a flower.  The energy obtained by the leaves is stored in a large tap root.  The second year after germination, this stored energy can be used to help produce the tall flower stalk.


This picture of a cluster of common mulleins was taken along the Raytharn Trail last week.  It is near the flower garden planted as a Boy Scout Project.  There are large spikes of flowers at the top of each plant.  However, it is apparent that not all the flowers on the spike bloom at once.  By producing flowers on the spike at few at a time, it increases the time during which at least some of the flowers will be open when pollinators pass by.  Common mulleins don’t grow well in dense grass, and are often found in areas of disturbed habitat.


Moth mullein is named because its reproductive group of stamens and pistils resemble the head of a moth.  The flowers can either be yellow or white.  The yellow variety is most common in Pennypack Preserve.  In other areas the white variety predominates (such as Ohio where I lived many years ago).  Moth mullein produces its flowers sequentially starting at the bottom of the stalk and working up to the top.  In the above photo the bottom flower has already fallen off, the middle flower is getting ready to fall, and the top flower is fully opened.  As with common mullein, this extends the time period over which flowers are available to pollinators.

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