Ask Mr. Smarty Plants

Mountain cedar, more properly known as Juniperus ashei (Ashe's juniper), is quite famous for inhibiting the growth of other plants under its canopy.  By creating heavy shade, drinking up much of the available water and through a type of chemical warfare known as allelopathy, Ashe juniper effectively eliminates most potential competitors beneath its boughs. 

However, there are a few native plant species that have found a niche in just that spot where they find little or no competition other than, of course, from the juniper itself.  Perhaps best known is Salvia roemeriana (cedar sage), a member of the mint family with very showy red flowers.  Cedar sage thrives in the shade of Ashe juniper.  Wedelia texana (hairy wedelia) also grows well there.  Another species that is much less showy, but is attractive in its own way, is Carex planostachys (cedar sedge).  Woody plants that are known to grow under junipers include Arbutus xalapensis (Texas madrone), Garrya ovata ssp. lindheimeri (Lindheimer's silktassel) and Cotinus obovatus (American smoketree).

Although junipers are conifers, they are not closely related to pines and do not produce pine needles.  The leaf litter that accumulates beneath junipers is usually referred to as juniper duff or cedar duff.