Apparently "Double Winner" was open polinated so any reports on the other parent are only conjecture.

Rcv. ROSALIE HALL is degronianum ssp. yakushimanum crossed with Double Winner. It is 2 ft x 2ft 5F(-15C) EM Flowers widely funnel-campanulate, 19 per truss; 8 rose red wavy lobes, fading to Neyron rose; short, strong red rays in throat; reverse Neyron rose. Dark green, obovate leaves; heavy brownish orange indumentum. Grayish yellow green new growth. Edna Newcomb, cross; H. Hall, reg. 1988.

I went to the ARS convention in Tulsa, OK. There they specialize in breeding for heat hardiness. The parent plant they found that imparts heat hardiness best is R. hyperythrum. Their work indicates that the main problem of heat intolerance is root rot. Apparently R. hyperythrum imparts fungus resistance to the plants making them somewhat immune to root rot. Apparently it also softens strong colors. Most of the work is done by John Thornton from Louisiana. One of the best is:

Rcv. 'Peppermint Twist'(hyperythrum X ÂPrincess ElizabethÂ) hardy to -15F. Hank Schannen carries this over at RareFind Nursery in NJ.

Rcv. WOODCOCK is Elizabeth crossed with hyperythrum,
3ft -10F, EM, Flowers rosy red. Leaves elongated;
growth compact. RHS Garden, Wisley, reg. 1972. P.C. 1971.
A.M. Wisley Trials 1986. Roslyn Nursery in Long Island is offering 'Woodcock', a rosy-flowered cross of 'Elizabeth' x hyperythrum from Wisley Gardens.

Rcv. BLAZING STAR is DelpÂs Fireking crossed with hyperythrum, 4ft x 3ft, -15F, strong red in bud opening to a central star of pale purplish pink, edges vivid purplish red on undersides. Trusses of 14 flowers. Weldon
Delp, cross 1986; reg. 1993.

Rcv. HYPERMAX is a Weldon Delp cross of hyperythrum with maximum. Large flowers of pale lavender with purple freckles, held in big trusses of 14. Plant medium-sized; hardy to -15F.

Rcv. OMO is a selected form of hyperythrum, 3ft, -15F, EM, rounded trusses of 8-10 white flowers, 5-lobed, funnel campanulate. Glossy, dark green leaves to 5.25in long. Captain C. Ingram, reg. 1976.

Rcv. RINGÂS EARLY SPLENDOR is hyperythrum crossed with catawbiense var. album Glass (Catalgla), 4.5ft x 3ft, -20F, 5 lobe flowers with frilled margins, strong purplish pink bud,opening white lightly flushed, then fading white; upper lobe heavily spotted deep purplish red; ball shape trusses 6in wide by 4.5in high, holding 20 flowers. Leaves held 2 years. Dr. Tom Ring, Bellaire, OH, cross 1979;

In trying to develop heat tolerant hybrids, Mr. K. Wada in Japan worked with species that he found resistant to high temperatures and high humidity in the Yokohama area. Some of these resistant species are:
R. tashiroi
R. metternichii, Aff.
R. metternichii, var. metternianum
R. arboreum, Blood Red
R. hyperythrum (or close to it)
R. scabrum
R. simiarum
R. mucronulatum
R. chapmanii
The last one he rates as one of the most dry air tolerant species in the world.

Rhodyman,

Thank you very much for the valuable information.
I see that Greer Gardens lists R. hyperythrum.
I may want to add this to my collection.
My goal is to make some crosses with Harold Amateis, but not using Jean Marie. It appears to me that Jean Marie dominates the foliage characteristics of it's progeny, which is not what I'm looking for. On the other hand, the red color of R. Taurus appears to have been dominated by strig.

If I could get a hardy, heat tolerant strig...