Re: [IGSROBIN] Geranium psilostemon; G. ruprechtii
I think Geranium psilostem is the largest geranium normal mortals can
grow, although G. arboreum from Maui in the Hawaiian Islands grows to
about 10-12 feet high, and as many feet wide, and is a large suckering
shrub. But its cultural requirements seem beyond most of us, unless you
happen to have an ancient, subtropical volcano in your backyard.
Actually G. psilostemon doesn't seem to grow particularly large for us.
Probably 3 1/2 - 4 feet high maximum. It seems to grow larger in
cooler, northern latitudes.
Geranium ruprechtii looks somewhat like a variation on G. pratense. It
comes from the Caucasus, and has mid to deep blue flowers on a large
plant 24-24". It blooms here in the spring and summer. It seems quite
cold tolerant, to USDA Zone 5.
Hardy geraniums are easy to grow from seed, if they are scarified
first.I usually scratch the fat end of the seed with a fine pin or
needle, and then sow in the usual way.