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December
1997
Sempervivum
species
November
1997
Allium
thunbergii
October
1997
Gentiana
scabra
September
1997
Sedum
cauticola
August
1997
Allium
senescens glaucum
July
1997
Delphinium
tatsienense
June
1997
Dianthus
gratianopolitanus
May
1997
Penstemon
rupicola
April
1997
Tulipa
tarda
March
1997
Iris
reticulata
February
1997
Saxifraga
longifolia
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2003
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2002
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2001
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2000
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1999
Archive
1998
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Plant
of the Month
May
1997
Penstemon
rupicola
by Iza Goroff
Penstemon
is a genus of North American plants containing about 300
species. Many of these are suitable for rock gardens, but of
these Penstemon
rupicola is one of the most
beautiful. It is an evergreen shrub with small (1/3 " -
3/4") leaves, usually rounded and somewhat gray in color.
There is some variation in height with the tallest usually
under 6" (15 cm) and the shortest as low as 3" (7 cm); all
are usually wider than tall.
Penstemon
rupicola requires at least a
half day of sun, but it is best in an East exposure in areas
with very hot summers. It needs a lean, sandy, well drained
acid soil.
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