Do early pollinations cause apathy in later flower production? The reason I ask is that I read somewhere that the plant focuses energy on sustaining current seed production over future flowers, so I’m wondering if there is some ideal point where you wait before attempting to pollinate?
Also do you guys prune your roses in spring if they have plenty of flowers, or do you guys prune at all? With the mild winter we had I had loads of buds but I pruned for the sake of future flowers, which I’m starting to regret as I had flower spikes with 15+ flowers which would’ve been ideal for pollination.
Definitely. The same way that deadheading encourages it. My season is not long enough to wait…I have about 5-6 weeks after initial spring blooming to make all my pollinations.
Except for keeping a plant “in bounds”, I only hard prune repeating roses in the very early spring. Once-bloomers are the same story, except that they get pruned after the spring flush (I do not currently use any once-bloomers for hybridizing).
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I’m finding that it varies depending on the rose and I assume this is one of the factors that experienced breeders use when evaluating potential seed parents.
Julie Andrews will accept pollen from anything and create giant hips with 30+ seeds, but the moment it sets hips it completely ceases to put out any more flowers or new growth for the next 90 days. Easy Bee-zy Knock Out is similarly accepting of foreign pollen, but its hips rarely contain more than 5 five seeds and it continues to push out new growth and massive sprays of flowers after going to seed. A lot of miniatures seem to behave similarly. Certain OGRs will rebloom for months until they’re allowed to set hips and then cease flowering for the rest of the year. Iceberg can set hips profusely or be seed-sterile depending on how hot it gets. And every single bloom on Lynnie will turn into a hip while it keeps pushing out new growth, yet it’ll stall out and abort most of them if it isn’t given supplemental water and shade during a heatwave.
There’s a lot of factors at play. Climate affects fertility and pollen viability in a number of ways. In hotter climates you can expect diminishing returns on late pollinations, but certain diploids will only self-pollinate in higher temperatures. Cold climate breeders risk losing any pollinations made after the first flush to frost. Californians are spoiled and live in the Garden of Eden. Moreover, a lot of these issues become less pronounced as the roses become more established and can also be subdued with fertilizing and shade cloth if that’s your thing.
In general, the single most energy-intensive thing any plant does in a given year is create fruit and seed. The annual cycles of rosaceae family plants revolve around that biological imperative. They bloom in early spring, create fruits, then spend most of the year growing and storing up carbohydrates in order to have an even bigger flush the next year.
I wouldn’t be surprised if modern roses, especially hybrid teas and English roses, have more of a tendency to shut down after going to seed because they were selectively bred to devote so much energy toward creating massive blooms on single stems.
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