Eritrichiums are among the most desired of blue-flowering plants; and, many times with many species have I, along with many others, have sought to find one that would actually last in the garden.
I have seen E. nanum growing high in the Big Horns in endless sheets, as if to challenge where earth and sky meet. Seed raising is straightforward and by treating with GA-3, germination occurs readily. The problem in Eastern North America is to deal with the higher humidity levels we have.
Eritrichium howardii grows at lower elevations in Wyoming, below 2000 meters, and so is exposed to much higher daytime temperatures. Its habitat is also very arid but not totally so. It grows more quickly than E. nanum and can eventually form small, tufted mounds 15 - 20 cm across covered with dark blue flowers in early spring. Easier and faster from seed, I have set out seedlings and most would transplant well enough into a coarse, humus-free soil and grow enough to present flowers the next spring. The heat and humidity of summer would weaken most; i.e., dead rosettes, and the survivors rarely would make it through the winter. And so I believed it was probably a short-lived perennial at best; but still worth growing for that wonderful flush of color in early April.
One year, at the EWSW in Ann Arbor (2002), I won a piece of tufa that had been core-drilled to make a sort of mini-trough. In April I planted it with 3 seedlings of E. howardii and set it in the garden in full light. 2 out of the 3 grew on and survived the summer approach the winter.
The most unsettling thing about E. howardii is that with hard frost, the leaves turn from gray/green to gray and by late March they can have a definite charcoal look - not very encouraging and morbid enough to bring on all sorts of recriminating thoughts. A careful peek into the center of each the tightly bound bundle of leaves reveals the faintest hint of green. Ahh!! only sleeping. The rush of light and warmth after the equinox brings a burst of growth so that in a week's time the whole plant revives.
To me, it is at its most attractive stage when the new leaves lay equally across the old - the point of resurrection. And so, in that tufa piece both plants did bloom magnificently, but one grew better than the other and in another year or so, only one survived. At this point, I thought, "well, maybe 3 years will be the end-not bad..." Well, it never did die and never seemed to mind the summer muggs or the wet snow of March.
Large enough now to take cuttings, I rooted a few and planted them in tufa, and these offsets did equally well. This last season I rooted 32 cuttings and raised another 40 or so seedlings. The 2 flats sit beside each other. Less than half of the seedlings remain. Only 2 of the cuttings died over the summer, and the difference in growth is immediately noticeable.
This summer has been wet, at times excessively so, but the Eritrichium has not faltered. Certainly plants from cuttings will grow more readily as general rule and the 'brush' of roots that a cutting develops are much easier to handle as a transplant. The original plant is now 6 years old and some 12 cm across, even with the extensive cutting it has been subjected to.
So, with some trepidation, I have named the form E. howardii 'Blue Sky' and will offer it in the catalogue for 2009. This cultivar is easy enough to grow in coarse, gravelly soil or directly into tufa. Oh, there are more things to do: cull the seedlings of this plant for other interesting forms; make some new trials with E. nanum, maybe the Asian species as they become available-but always looking for the growable.