west Houston, TX (Zone 9a) | August 2006 | positive
Harvard penstemon is the showiest of the native Texas scarlet penstemons and has been used by professional gardeners and landscape design...Read Moreers in Texas for many years. Keep it on the dry side (it can survive on only 10" of rainfall a year) or it easily can attain a height of 6 feet. It spends most of its life as a rosette of thick, pale leaves. After its done with its late spring bloom in Texas (April to June) you will probably want to cut back the stalks; although if you don't it will probably rebloom in October. Hummingbirds love this native penstemon. There are 3 other tall native Texas scarlet penstemons: P murrayanus, P. cardinalis, and P. barbatus. This is a seperate species from them with its own unique characteristics. This particular species is best reproduced from seed, transplants often fail.
Penstemon havardii is endemic to the limestone soils of the Trans-Pecos in Texas but will tolerate sand, loam, clay, and limestone soils as long as they are well drained. I grow this plant in Houston Texas in extremely raised, dry bed conditions. It is beautiful when in full bloom.
Harvard penstemon is the showiest of the native Texas scarlet penstemons and has been used by professional gardeners and landscape design...Read More