- 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...
- (2003).
Growing penstemons : species, cultivars, and hybrids. Haverford, PA:
Infinity Pub. pp. 93–94. ISBN 0741415291. "
Penstemon whipple**** Whipple's...
- 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...
-
closely related mat
penstemon or Thompson's
beardtongue by the
penstemon experts David Way and
Peter James. As is
typical of
penstemons, they
require well...
- non-profit
NatureServe evaluated Penstemon eatonii in 1990 and at that time
rated it as
secure (G5).
Unlike penstemons that are
adapted to pollination...
-
Penstemon digitalis (known by the
common names foxglove beard-tongue,
foxglove beardtongue,
talus slope penstemon, and
white beardtongue) is a species...
-
Penstemon gairdneri is a
species of
perennial plant in the
Plantaginaceae family with the
common name Gairdner's beardtongue. It is
native to Washington...
- gardener's
guide to
growing penstemons. N:
David & Charles. pp. 29, 85. ISBN 978-0-88192-424-4. "
Penstemon caespitosus - mat
penstemon".
Garden Explorer. Santa...
- Nold,
Robert (1999).
Penstemons (1st ed.). Portland, Or.:
Timber Press. p. 97. ISBN 0881924296. Reese, R. (3
November 2016). "
Penstemon albidus".
South Dakota...
- 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...
