- ISBN 0-7153-0550-6 Nold, Robert.
Penstemons.
Timber Press. 1999. ISBN 0-88192-429-6 Lindgren, Dale T.
Growing penstemons : species, cultivars, and hybrids...
- one of the few
scented penstemons. The plant, in the
family Plantaginaceae, is
named after the
botanist Edward Palmer.
Penstemon palmeri is
native to desert...
-
consists of
clusters of
tubular blue to
purple flowers.
Penstemon serrulatus is one of the few
penstemons to
occur at low
elevations along the
Pacific Northwest...
-
regard bush
penstemons as one of the best
penstemons to grow in gardens. In hot, dry
environments with well
draining soil bush
penstemon are recommended...
-
Species in the
genus Penstemon are
commonly called penstemons or
beardtongues in English, and they will
often have a
common name
based on either. As the...
- Nold,
Robert (1999).
Penstemons (1st ed.). Portland, Or.:
Timber Press. p. 97. ISBN 0881924296. Reese, R. (3
November 2016). "
Penstemon albidus".
South Dakota...
- (2003).
Growing penstemons : species, cultivars, and hybrids. Haverford, PA:
Infinity Pub. pp. 91–92. ISBN 0741415291. "
Penstemon virens". Navigate...
- gardener's
guide to
growing penstemons.
Newton Abbot (England):
David & Charles. p. 82. ISBN 0-88192-424-5. Nold,
Robert (1999).
Penstemons (1st ed.). Portland...
- PMC 5554440. PMID 28828248. Straw,
Richard (1962). "The
Penstemons of
Mexico II:
Penstemon hartwegii,
Penstemon gentianoides, and
their allies". Boletín de la...
-
Penstemon spectabilis is a
species of
penstemon known by the
common name
showy penstemon or
showy beardtongue. It is a
perennial herb
native to southern...
