Looking for seed parents which won’t abort under daily 90-100 degree heat.
Sadly there is only a short spring window where most of my roses actually set hips, and it’s during thunderstorm season so I lost a lot of those to crazy rain and hail, leaving me to discover that only one of my seed parents semi-reliably set hips in the hot, humid summer. And even then I still had lots of aborts and those that survived didn’t produce many seeds.
At this point I really don’t even care about the attributes of the rose, I’ll take any rose that can be used as a broodmare under high heat and rain.
I live in Penrith, Australia and regularly receive those temperatures. I find that if you conduct crosses from rose that you have produced in those conditions, then they are more likely to be successful in those conditions.
This was my first year cross-pollinating so I’ll wind up doing that next year just by virtue of that. But regardless that does seem like a good thought to keep in mind moving forward.
In view of the above observation, can anybody vouch for roses from hybridizers in e.g. Spain or Italy being viable parents for those in hot (dry) climates? I have Barni’s Perfume Breeze but no others. She does not set many hips for me.
I will say that some of Delbard’s roses appear fertile here in Cenral Texas, and Carefree Beauty (“Katy Road Pink" when I was first introduced to her as a “found rose") is the most reliable seed setter for me. (Most of my breeding is finished by mid spring in my climate so by fertility, I am speaking mostly of not aborting hips in the heat.)
Back in Sydney (hot, not necessarily dry, depending on drought/flood cycles) some of the delbard painters were fairly seed fertile (grimaldi/alfred sisley) but health was eh, spot and then near total defoliate, then leaf out and repeat (henri mattisse was healthier and heat never seemed to bother it but seed fertility was a struggle).
Potential easy mode if really not bothered by plant traits….hybrid musks, many set super easy with moderns and germinate like weeds.
From many years of enduring mid California desert, inland valley heat, it appeared most modern roses retained their ripening hips as long as they were provided with some shade protection during the worst of the daily heat and they were kept properly watered. Nothing held and ripened hips if they were exposed to the brutal hot sun all day or if I missed watering when I should have. It also seemed those most likely to hold the hips were also those most likely to form them in the first place. Anything hit and miss in the best of conditions was sure to fail at the extremes while the “fertile Myrtles” held them the most reliably no matter what happened.
Kim’s comment about shading your seed bearers is relevant. Set up a 50% shade cloth cover and you should be good.
That said, any of the roses Ralph Moore used as parents should be worth trying, as his greenhouse’s often experiences 120F temps for months on end, and he had no difficulty generating obscene volumes of seeds.
I knew my laziness would come around to bite me when I opted not to put up a shade cloth. That also tracks because I moved my potted seed parents to the one spot in my front yard where there’s afternoon protection. Geographically I’ve got a kind of all or nothing setup when it comes to sun/shade. Probably didn’t help that a lot of my efforts were with wild foliolosa pollen, which in general has proven to be a stubborn species.
The good news is that my plans for next year largely gravitate around Basye’s Legacy and 0-47-19.
Sequoia held their seed parents either under shade cloth or inside “green houses” of plastic sheeting which usually had white wash splattered on its outer surface to reduce the light transmission. That heat produces two issues…one is the literal frying of sensitive reproductive parts from the extreme heat and burning sun. The second is the associated water stress caused by the extreme transpiration of water and potential shortage of water available to be absorbed by the roots. Water stress any time during the hip (fruit) development can trigger aborting the hips. Whatever you can do to reduce those issues should improve your chances.