Sunday, July 17, 2011

American Bellflower Update

American Bellflower, in bloom from
late June through August

Over a year ago I posted some information on the American Bellflower, Campanulastrum americanum.  This plant, or it's progeny anyway (it's a biennial) have been growing in my yard since 2008.  It spends its first year as a rather innocuous rosette of leaves, but in its second year it shoots up to form a flower stalk between 2 and 6 feet in height, depending on location.  This spring I had an over abundance of second year plants within about 5 feet of the 2009 plants that I let go to seed. This spread is consistent with the smooth round seed just falling to the ground from the tall flower stalks.  Not wanting to throw any of these seedlings out, I redistributed them to a variety of areas in my yard that are normally difficult for growing flowering plants. 

A spontaneous composition on
the edge of the driveway with
Spiarea latifolia, the blue
Campanulastrum and
Rudbecia hirta.
The Campanulstrum growing in
dry shade under a Crabapplealong a foundation.

Along the North side, here the Hostas
hide the legginess of the Bellflower

Growing in rocky soil from under the
deck - plants forming a screen.

It seems that the plant looks better in some of the more challenging locations, where its vigor is moderated.  In rich soil with lots of sun it can become a floppy 6 foot monster.  Some places where it is doing nicely are : cracks in the driveway, a sterile rocky area under a deck, north side of the house, under a Norway Maple and in the deep shade of a Crab Apple along a dry foundation.  I think this latter location shows the American Bellflower at its best.

As far as pollinators, it seems that there is one particular bee, probably a type of Mason or Miner Bee (can anyone ID this for me?), that really loves this plant.  The first couple of years I didn't see much action with bees, but this year the bee activity has taken off!  A few larger bumblebees drop in, but they prefer the Meadowsweet (Spiarea latifolia var. alba) for the most part.

The meadowsweet is preferred by the bumblebees
I have been a little concerned with how vigorously this plant reproduces, however it is fairly easy to pull up so it can be controlled in the garden fairly easily.  It is not as aggressive a reseeder as my Bearded Beggarticks (Bidens aristosa), which I am glad to say is easily edited out by selective pulling.  The question of persistance of the seed remains.  How many years will it lie dormant in the soil? 

Also, since this bellflower is not a Massachusetts native, I wouldn't recommend its use near wild areas in this state.  But I do think it works well as a North American native that is well adapted to the conditions of the modern residential landscape, particularly under trees and along shady foundations.

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