I spent a little over an hour on Saturday pulling just one type of weed from the birdsong garden.  The weather was beautiful and there was a pleasant wind which made weeding less a chore.  This is a common weed known as Horseweed and can grow in almost any area of your garden. The weed can grow as tall as 2 meters, well taller than myself, and reproduces by seed.  The seeds germinate in late summer or early spring.

The good thing about these weeds is that they have extremely shallow root systems 
and you can pull them out quite easily.  
Below, find additional photos of the Garden
The Birdsong Garden

The new Teepee
A view from the new Teepee

Ornamental Grasses flowing in the wind