Cork -

Gillian has really heavy blossoms. Lyon's Plum Pudding as I remember has short bloomstalks. If you very carefully redirect buds from under the leaves before they open, it can be done - but you probably break some of them.

Very double blossoms are so heavy - the bloomstalks are not that strong to keep something like Gillian upright. Single blossoms usually behave better.

If you think - the oldies quite often have weak bloomstalks and modern hybrids are selected to have stronger ones. So most of it is genetics, but I think if you have high light, the bloomstalks become shorter and blossoms hide more.

I.