Morden Centennial offspring no juvenile bloom?

I’m starting to notice a pattern with my Morden Centennial seedlings: they don’t seem to bloom their first season, even with modern reblooming parents. Has anybody else noticed this?



That is the way ‘Morden Centennial’ is. Underused in rose breeding programs it seems to me, but I use it a lot.

Thanks Paul, that’s reassuring. I have a couple that look healthy this year, so I’ll hold onto them.

Peter Harris (1975) reported that many ‘Golden Shower’ seedlings did not bloom the first year.

Judging also by the low percentage of first-time bloomers it produces, GS is not a lazy hybridizer’s dream seed parent. Only two crosses (x Spartan, x Circus) have produced more than 50% Bloomers for me, and most crosses on GS average only 20% to 40% Bloomers. The crosses yielding in the 40% to 50% range are these: x Tropicana, x Floradora, x Charlotte Armstrong, x First Prize.

The fact that ‘Golden Showers’ reblooms freely in a suitable climate (San Jose area of California, for example, but not Northeastern Kansas) suggests that juvenile bloom is not the same thing as everblooming. Rather, precocity seems to be an independent character.

Do the ‘Morden Centennial’ offspring rebloom freely in the second or third year?



It seems ‘Morden Centennial’ has limited ability to produce repeat bloom in its progeny. It has to be kept in mind that ‘Morden Belle’, introduced in 2004, was considered the replacement for ‘Morden Centennial’, partly because it repeated its bloom better. However, I prefer growing and breeding the latter cultivar to the former one.

It just occurred to me though that combining ‘Never Alone’ with ‘Morden Belle’ might be good to do, since there will be a double dose of ‘Scarlet Meidiland’ in the parentage of its progeny. It’s this cultivar that is likely responsible for the very good foliage of both cultivars.

For Karl: A tangent here- Golden Showers, and High Noon both were able to rebloom for me in the same NE KS location as yours, when growing in pots with lots of water, and some fertilizer. Hardly anything reblooms well here under typical summers without both.

I agree that precocity and (abundance of) rebloom may well be conditioned by different genes. This spring I had a very double pink bloom on a Therese Bugnet seedling at about 6 weeks inside under continuous lighting. Since then it has grown into a decent sized plant outside under normal daylength without a sign of wanting to repeat, behaving like a rugosa. I hope that next year it is a freer bloomer. I sort of wonder if perhaps the first flower was determined in the seed.

This may be a bit of an odd year. The Dr Huey up the street has had a second flush of bloom from mid-June until today. I need to go talk with the owner.

My mother had ‘Golden Showers’ growing in very clayey soil. The poor thing didn’t stand a chance. It just stopped growing in the heat of summer, so there was no chance of bloom until late in the season.

Odd is right. The plant I believe is ‘Paul’s Scarlet Climber’ has had a second flush this year. Another couple of plants growing down the street have also had a few extra blooms.